WO2009001214A2

WO2009001214A2 - Thieno[2,3-d]pyrimidin-4(3h)-one, isoxazolo[5,4-d]pyrimidin-4(5h)-one and isothiazolo[5,4-d]pyrimidin-4(5h)-one derivatives as calcium receptor antagonists

Info

Publication number: WO2009001214A2
Application number: PCT/IB2008/001745
Authority: WO
Inventors: Feng Bi; Mary Theresa Didiuk; Angel Guzman-Perez; David Andrew Griffith; Kevin Kun-Chin Liu; Daniel Patrick Walker; Michael Paul Zawistoski
Original assignee: Pfizer Products Inc.
Priority date: 2007-06-28
Filing date: 2008-06-16
Publication date: 2008-12-31
Also published as: WO2009001214A3

Abstract

The present invention is directed to novel thieno[2,3-d]pyrimidin-4(3H)-one, isoxazolo[5,4-d]pyrimidin-4(5H)-one and isothiazolo[5,4-d]pyrimidin-4(5H)-one derivatives and pharmaceutically acceptable salts thereof of structural formula (I), wherein the variables R1, R2, R3, X and Z are as described herein. Also provided are pharmaceutical compositions comprising the compounds of formula I as well as methods of treatment employing compounds of formula I to treat a disease or disorder characterized by abnormal bone or mineral homeostasis such as hypoparathyroidism, osteoporosis, osteopenia, periodontal disease, Paget's disease, bone fracture, osteoarthritis, rheumatoid arthritis, and humoral hypercalcemia of malignancy.

Description

THIENO[2,3-cy]PYRIMIDIN-4(3H)-ONE, ISOXAZOLO[5,4-cy]PYRIMIDIN-4(5H)-ONE

AND ISOTHIAZOLO[5,4-d]PYRIMIDIN-4(5H)-ONE DERIVATIVES

AS CALCIUM RECEPTOR ANTAGONISTS

FIELD OF INVENTION

The present invention is directed toward novel thieno[2,3-d]pyrimidin-4(3H)-one, isoxazolo[5,4-d]pyrimidin-4(5H)-one and isothiazolo[5,4-d]pyrimidin-4(5H)-one derivatives, pharmaceutical compositions containing these compounds, methods for their use and processes for their production. These novel compounds are able to inhibit calcium receptor activity and thus act as calcium receptor antagonists.

BACKGROUND OF THE INVENTION

In mammals, extracellular Ca²⁺ is under rigid homeostatic control with the serum calcium concentration strictly maintained at a concentration of approximately 1.1 to 1.3 mM in a healthy mammal. The extracellular Ca²⁺ homeostasis depends on integrated regulation of Ca²⁺ fluxes with respect to the intestine, kidneys and bone. The extracellular Ca²⁺ regulates various processes such as blood coagulation, nerve and muscle excitability, and normal bone homeostasis. When the Ca²⁺ serum concentration decreases by 50% tetania occurs, and when the Ca²⁺ serum concentration increases by 50% consciousness is clouded, in both instances a potentially life threatening circumstance. Extracellular Ca²⁺ also inhibits the secretion of parathyroid hormone (PTH) from parathyroid cells, inhibits bone resorption by osteoclasts, stimulates secretion of calcitonin from C-cells and is involved in re-absorption and excretion in the kidney.

The extracellular calcium-sensing receptor (CaSR) is a hormone-like receptor, more particularly a plasma membrane-bound G protein-coupled receptor (GPCR) that belongs to family 3 of the GPCR superfamily. Family 3 of the GPCR superfamily includes metabotropic glutamate receptors (mGluRs), γ-aminobutyric acid B-type receptors (GABABRS) as well as putative pheromone and taste receptors. The CaSR has a large extracellular domain exhibiting "Venus flytrap" topology, a seven- transmembrane domain and a relatively large cytoplasmic domain. Human CaSR consists of 1078 amino acids and shares 93% amino acid homology with bovine CaSR. The CaSR senses and is activated by changes in extracellular Ca²⁺ levels. The presence of CaSR on certain specialized cells enables those Ca²⁺-sensing cells to respond to changes in extracellular Ca²⁺ concentration. Examples of Ca²⁺-sensing cells include the parathyroid-secreting cells of the parathyroid gland, the calcitonin-secreting C cells of the thyroid gland and certain cells in the kidney. In addition, the CaSR has been found in a wide variety of other tissues including intestine, bone, bone marrow, brain, skin, pancreas, lung and heart.

The CaSR on the surface of parathyroid chief cells is the primary entity that regulates secretion of PTH from parathyroid cells. Activation of the CaSR on parathyroid chief cells by extracellular Ca²⁺ suppresses PTH production and secretion, inhibits parathyroid cellular proliferation and likely inhibits PTH gene expression. The CaSR on the surface of the calcitonin-secreting C cells of the thyroid gland mediate the stimulatory action of high extracellular Ca²⁺ concentration on calcitonin secretion, thereby increasing the circulating level of the Ca²⁺-lowering hormone calcitonin. The CaSR is also present in the kidney, along much of the nephrons and at the basolateral surface in the cortical thick ascending limb. In the basolateral surface in the cortical thick ascending limb the CaSR is thought to mediate high Ca²⁺-induced inhibition of the tubular re-absorption of Ca²⁺ and magnesium. A reduction of renal cortical synthesis of 1 ,25(OH)₂ vitamin D and polyuria with dilute urine are partially the result of hypercalcaemic activation of the CaSR in the nephron. PTH is the primary endocrine hormone regulating Ca²⁺ homeostasis in the blood and extracellular fluids. PTH, by acting on bone and kidney cells, increases the level of Ca²⁺ in the plasma. This increase in plasma Ca²⁺ concentration then acts as a negative feedback signal, thereby depressing PTH secretion. The reciprocal relationship between extracellular Ca²⁺ and PTH secretion forms an important mechanism for maintaining bodily Ca²⁺ homeostasis. PTH has been found to increase bone turnover, but the overall effect on bone is dependent on temporal changes in circulating levels of PTH. Sustained elevations in circulating plasma PTH levels, as occurs in hyperparathyroidism, have been found to result in a net catabolic effect on bone. By contrast, transient increases in plasma PTH levels, achieved by daily or near daily injection of exogenous hormone, have been found to exhibit a net anabolic effect on bone. The effect of PTH on bone is likely due to PTH being able to induce a rapid release of calcium from bone and mediate other changes by acting directly on osteoblasts and indirectly on osteoclasts. PTH affects cellular metabolic activity, ion transport, cell shape, gene transcriptional activity and secretion of proteases in osteoblasts. Also, PTH stimulates the production of RANKL, a protein that plays a crucial role in osteoclast differentiation and activity.

Various compounds are known to modulate the effects of extracellular Ca²⁺ on the CaSR. Calcimimetics are agents that act as allosteric modulators of the CaSR that increase the sensitivity of the CaSR to activation by extracellular Ca²⁺. Calcilytics, or calcium receptor antagonists, are agents that act as modulators of the CaSR that inhibit CaSR activity. This inhibition of the CaSR activity results in a decrease of one or more CaSR activities that are evoked by extracellular Ca²⁺. Certain urea derivatives, such as those disclosed in PCT International

Publication WO 02/059102, are described as having calcimimetic activity. In addition, certain phenylalkylamine derivatives have been identified as calcimimetics. Phenylalkylamine calcimimetic compounds include (R)-N-(I -(3-methoxyphenyl)ethyl)-3- phenylpropan-1 -amine hydrochloride (NPS-467); (f?)-3-(2-chlorophenyl)-N-(1-(3- methoxyphenyl)ethyl)propan-1 -amine hydrochloride (NPS R-568, tecalcet hydrochloride) and (R)-(-)-N-(1-(naphthalen-1-yl)ethyl)-3-(3- (trifluoromethyl)phenyl)propan-1 -amine hydrochloride (NPS-1493, cinacalcet hydrochloride). Cinacalcet hydrochloride and uses thereof are disclosed in U.S. Patent Nos. 6,011 ,068; 6,031003; 6,211 ,244 and 6,313,146. Cinacalcet hydrochloride is marketed as Sensipar® and Minpara® in the U.S. and Europe, respectively, and is indicated for the treatment of secondary hyperparathyroidism in patients with chronic kidney disease on dialysis and for hypercalcemia in patients with parathyroid carcinoma.

Calcilytics, or calcium receptor antagonists, have been described in various publications such as PCT International Publication Nos. WO 93/04373; WO 94/18959; WO 95/11211 ; WO 97/37967; WO 98/44925; WO 98/45255; WO 99/51241 ; WO 99/51569; WO 00/45816; WO 02/14259; WO 02/38106; WO 2004/041755; and WO 2005/030746; Nemeth, E.F.; Journal of Molecular Endocrinology (2002) 29, 15-21; Kessler, A. et al.; ChemBioChem (2004) 5, 1131 ; Steddon, S.J. et al.; Lancet (2005) 365, 2237-2239; and Shcherbakova, I.; et al.; Bioorganic & Medicinal Chemistry Letters (2005) 15, 1557-1560.

Calcium receptor antagonists are useful in the treatment of various disease states characterized by abnormal levels of one or more components, e.g., polypeptides such as hormones, enzymes or growth factors, the expression and/or secretion of which is regulated or affected by activity at one or more CaSR. Target diseases or disorders for calcium receptor antagonists include diseases involving abnormal bone and mineral homeostasis. Abnormal calcium homeostasis is characterized by one or more of the following activities: an abnormal increase or decrease in serum calcium; an abnormal increase or decrease in urinary excretion of calcium; an abnormal increase or decrease in bone calcium levels (for example, as assessed by bone mineral density measurements); an abnormal absorption of dietary calcium; an abnormal increase or decrease in the production and/or release of messengers which affect serum calcium levels such as PTH and calcitonin; and an abnormal change in the response elicited by messengers which affect serum calcium levels.

The novel calcium receptor antagonists of this invention are useful in the treatment of diseases associated with abnormal bone or mineral homeostasis. Thus, these calcium receptor antagonists are useful in the treatment of hypoparathyroidism, osteoporosis, osteopenia, periodontal disease, bone fracture, osteoarthritis, rheumatoid arthritis, Paget's disease, humoral hypercalcemia associated with malignancy.

SUMMARY OF THE INVENTION

The present invention is directed towards calcium receptor antagonist compounds, pharmaceutical compositions containing the calcium receptor antagonist compounds and methods of treatment employing the calcium receptor antagonist compounds.

More specifically, the present invention is directed to calcium receptor antagonists that are thieno[2,3-d]pyrimidin-4(3H)-one, isoxazolo[5,4-d]pyrimidin-4(5H)- one or isothiazolo[5,4-d]pyrimidin-4(5H)-one pyrido[4,3-c/]pyrimidin-4(3H)-one derivatives of structural formula I

wherein

R¹ is Q or Q-(Ci-C₆)alkyl-; wherein the (CrC₆)alkyl portion of said Q-(C_rC₆)alkyl- is optionally substituted with one to three substituents independently selected from fluoro, hydroxy or methoxy; R² is (Ci-C₆)alkyl, (C₃-C₇)cycloalkyl, aryl or heteroaryl; wherein said (CrC₆)alkyl, (C₃- C₇)cycloalkyl, aryl or heteroaryl is optionally substituted with one to three substituents independently selected from halo, cyano, hydroxy-(CrC₄)alkyl, (Ci-C₆)alkyl, amino, (Cr C₆)alkylamino-, di(Ci-C₆)alkylamino-, (Ci-Cβjalkylcarboxamido-, (Cr C₆)alkoxycarboxamido-, (CrCβJalkylcarbonyl, (CrCβJalkylsulfonamido-, (C₁-C₆JaIkOXy or hydroxy; wherein said (CrCβ)alkyi, (Ci-Cβjalkylamino-, di(Ci-C₆)alkylamino-, (C₁- Cβjalkylcarboxamido-, (CrCβJalkoxycarboxamido-, (Ci-C₆)alkylcarbonyl, (C₁- C₆)alkylsulfonamido-, or (C_rC₆)alkoxy substituent is optionally substituted independently with one to three halo; X is CR⁴ or N; Z is S or O; provided that Z is S when X is CR⁴;

R³ is hydrogen, halo, (d-C₆)alkyl, (C₃-C₇)cycloalkyl, Q-(Ci-C₆)alkyl-, aryl, heteroaryl, cyano, OR⁵, SR⁵, NR⁶R⁷, C(O)R⁶, CO₂R⁶ or C(O)NR⁶R⁷; wherein said (Ci-C_β)alkyl, (C₃- C₇)cycloalkyl, aryl or heteroaryl is optionally substituted with one to three substituents independently selected from halo, cyano, trifluoromethyl, trifluoromethoxy, (Ci-Cβ)alkyl; (Ci-C₆)alkoxy, NR⁶R⁷ or hydroxy; R⁴ is hydrogen, halo, cyano, (Ci-C₆)alkyl optionally substituted independently with one to three fluoro, aryl, heteroaryl, or OR⁵;

R⁵ at each occurrence is independently (Ci-Cβjalkyl, (C₃-C₇)cycloalkyl, (C₃- C₇)cycloalkyl-(Ci-C₆)alkyl-, aryl, heteroaryl, aryl(Ci-C₆)alkyl-, or heteroaryl(Ci-C₆)alkyl-; each of said (C_rC₆)alkyl, (C₃-C₇)cycloalkyl, (C₃-C₇)cycloalkyl-(Ci-C₆)alkyl-, aryl, heteroaryl, aryl(Ci-C₆)alkyl- or heteroaryl(Ci-C₆)alkyl- optionally substituted with one to three substituents independently selected from halo, hydroxy or (CrC₃)alkyl; R⁶ and R⁷, at each occurrence, are independently hydrogen, (CrC₆)alkyl, or (C₃- C₇)cycloalkyl; or R⁶ and R⁷ taken together with the nitrogen atom to which they are attached form a 3 to 7 membered fully saturated, partially saturated or fully unsaturated ring optionally containing one to two additional heteroatoms independently selected from N(R⁸J_n; O or S(O)_P; n is 0 or 1 , p is O₁ 1 or 2; R⁸ is hydrogen or (d-C₆)alkyl; Q, at each occurrence, is independently (C₃-C₇)cycloalkyl, aryl or heteroaryl; wherein said aryl or heteroaryl is optionally substituted with one to three substituents independently selected from halo, cyano, trifluoromethyl, trifluoromethoxy, (CrCβJalkyl or (Ci-Cβ)alkoxy; or a pharmaceutically acceptable salt thereof. "Halo" refers to fluoro, chloro, bromo or iodo.

"(CrCβJalkyl" refers to a hydrocarbon group having one to six carbon atoms joined together by single carbon-carbon bonds. The (CrCβJalkyl group may be straight- chain or contain one or more branches and may be unsubstituted or substituted as specified. Examples of (C-i-CβJalkyl groups include methyl, ethyl, n-propyl, isopropyl, n- butyl, sec-butyl, tert-butyl, n-pentyl, (i-methyl)butyl, (2-methyl)butyl, (3-methyl)butyl, (1 ,2-dimethyl)propyl, n-hexyl, (i-methyl)pentyl, (2-methyl)pentyl, (3-methyl)pentyl, (4- methyl)pentyl, (i-ethyl)butyl, (2-ethyl)butyl, (1 ,2-dimethyl)butyl, (1 ,3-dimethyl)butyl, (2,3- dimethyl)butyl and the like. It is to be understood that a (CrC₆)alkyl group encompasses other lower alkyl groups such as (CrC₄)alkyl or (C-ι-C₂)alkyl groups having one to four and one to two carbon atoms, respectively.

"(CrCβJalkoxy" refers to an oxygen joined to a (Ci-C₆)alkyl group. The (Ci- Cβ)alkyl group in the (Ci-C₆)alkoxy moiety may be straight-chain or contain one or more branches and may be unsubstituted or substituted as specified. Examples of (C-i- C₆)alkoxy groups include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec- butoxy, tert-butoxy, n-pentoxy and the like. Likewise, alkyl or alkoxy groups of differing lengths, as denoted by the number of carbons present in those groups, are defined in the same manner. "(C₃-C₇)cycloalkyl" refers to a saturated carbocyclic group having three to seven carbons and encompasses cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and cycloheptyl. The (C₃-C₇)cycloalkyl group can be unsubstituted or substituted as specified.

"(Ci-C₆)alkylcarboxamido-" refers to the group (C_rC₆)alkylC(O)NH-. "(C₁- C₆)alkoxycarboxamido-" refers to the group (C₁-C₆JaIkOXyC(O)NH-. "(C₁- C₆)alkylsulfonamido-" refers to the group (C₁-C₆)alkylS(O)₂NH-.

"Aryl" refers to a six to sixteen membered carbocyclic aromatic group having at least one ring with a conjugated pi-electron system. The aryl group can have conjugated or fused rings and can be unsubstituted or substituted as specified. Examples of aryl groups include phenyl, naphthalenyl, anthracenyl, phenanthrenyl, azulenyl and biphenyl.

"Heteroaryl" refers to a five to sixteen membered aromatic group with at least one ring with a conjugated pi-electron system and containing one to four heteroatoms such as N, O or S. The hetroaryl group can have conjugated or fused rings and can be unsubstituted or substituted as specified. Examples of heteroaryl groups include thienyl, furanyl, pyrrolyl, pyrazolyl, imidazoyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, triazolyl, oxadiazolyl, thiadiazolyl, tetrazolyl, pyridinyl, pyridizinyl, pyrimidinyl, pyrazinyl, triazinyl, indolyl, isoindolyl, indolizinyl, benzofuranyl, benzothienyl, indazolyl, benzimidazoyl, benzthiazolyl, purinyl, quinolizinyl, quinolinyl, isoquinolinyl, cinnolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, naphthyridinyl, pteridinyl, carbazolyl, acridinyl, phenazinyl, phenothiazinyl or phenoxazinyl.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a chart depicting plasma PTH levels from the time of intravenous injection to 240 minutes following intravenous injection of 1 mg/kg of the compound of Example 42, (/?)-2,2,2-trifluoiO-N-(2-(4-oxo-5-(1 -phenylpropan-2-yl)-3-(trifluoromethyl)- 4,5-dihydroisoxazolo[5,4-d]pyrimidin-6-yl)pyridin-3-yl)acetamide, in normal rats. DETAILED DESCRIPTION OF THE INVENTION The present invention provides novel thieno[2,3-d]pyrimidin-4(3H)-one, isoxazolo[5,4-d]pyrimidin-4(5H)-one and isothiazolo[5,4-d]pyrimidin-4(5H)-one derivatives and pharmaceutically acceptable salts thereof of structural formula I

wherein the variables R¹, R², R³, X and Z are described hereinabove. The pharmaceutically acceptable salts of the compounds of formula I include the acid addition and base salts (including disalts) thereof. Suitable acid addition salts are formed from acids which form non-toxic salts.

Examples include the acetate, aspartate, benzoate, besylate, bicarbonate/carbonate, bisulphate/sulphate, borate, camsylate, citrate, edisylate, esylate, formate, fumarate, gluceptate, gluconate, glucuronate, hexafluorophosphate, hibenzate, hydrochloride/chloride, hydrobromide/bromide, hydroiodide/iodide, isethionate, lactate, malate, maleate, malonate, mesylate, methylsulphate, naphthylate, 2-napsylate, nicotinate, nitrate, orotate, oxalate, palmitate, pamoate, phosphate/hydrogen phosphate/dihydrogen phosphate, saccharate, stearate, succinate, tartrate, tosylate and trifluoroacetate salts.

Suitable base salts are formed from bases which form non-toxic salts. Examples include the aluminium, arginine, benzathine, calcium, choline, diethylamine, diolamine, glycine, lysine, magnesium, meglumine, olamine, potassium, sodium, tromethamine and zinc salts. For a review on suitable salts, see "Handbook of Pharmaceutical Salts: Properties, Selection, and Use" by Stahl and Wermuth (Wiley-VCH, Weinheim, Germany, 2002). A pharmaceutically acceptable salt of a compound of formula I may be readily prepared by mixing together solutions of the compound of formula I and the desired acid or base, as appropriate. The salt may precipitate from solution and be collected by filtration or may be recovered by evaporation of the solvent. The degree of ionization in the salt may vary from completely ionized to almost non-ionized. The compounds of the invention include compounds of formula I as hereinbefore defined, polymorphs, and isomers thereof (including optical, geometric and tautomeric isomers) as hereinafter defined and isotopically-labeled compounds of formula I.

The compounds of the present invention may be administered as prodrugs. Thus certain derivatives of compounds of formula I which may have little or no pharmacological activity themselves can, when administered into or onto the body, be converted into compounds of formula I having the desired activity, for example, by hydrolytic cleavage. Such derivatives are referred to as 'prodrugs'. Further information on the use of prodrugs may be found in 'Pro-drugs as Novel Delivery Systems, Vol. 14, ACS Symposium Series (T Higuchi and W Stella) and 'Bioreversible Carriers in Drug Design', Pergamon Press, 1987 (ed. E B Roche, American Pharmaceutical Association).

Prodrugs can, for example, be produced by replacing appropriate functionalities present in the compounds of formula I with certain moieties known to those skilled in the art as 'pro-moieties' as described, for example, in "Design of Prodrugs" by H Bundgaard (Elsevier, 1985).

Some examples of such prodrugs include:

(i) where the compound of formula I contains a carboxylic acid functionality (-COOH), an ester thereof, for example, replacement of the hydrogen with (Ci-Cβ)alkyl; (ii) where the compound of formula I contains an alcohol functionality (-OH), an ether thereof, for example, replacement of the hydrogen with (Ci-C₆)alkanoyloxymethyl; and (iii) where the compound of formula I contains a primary or secondary amino functionality (-Nhkor -NHR where R is not H), an amide thereof, for example, replacement of one or both hydrogens with (Ci-Ci₀)alkanoyl. Further examples of replacement groups in accordance with the foregoing examples and examples of other prodrug types may be found in the aforementioned references. Finally, certain compounds of formula I may themselves act as prodrugs of other compounds of formula I.

Compounds of formula I containing one or more asymmetric carbon atoms can exist as two or more stereoisomers. Where a compound of formula I contains an alkenyl or alkenylene group, geometric cis/trans (or ZJE) isomers are possible. Where the compound contains, for example, a keto or oxime group or an aromatic moiety, tautomeric isomerism ('tautomerism') can occur. It follows that a single compound may exhibit more than one type of isomerism. Included within the scope of the claimed compounds of formula I are all stereoisomers, geometric isomers and tautomeric forms of the compounds of formula I, including compounds exhibiting more than one type of isomerism, and mixtures of one or more thereof. Also included are acid addition or base salts wherein the counterion is optically active, for example, D-lactate or L-lysine, or racemic, for example, DL-tartrate or DL-arginine. Cis/trans isomers may be separated by conventional techniques well known to those skilled in the art, for example, chromatography and fractional crystallisation. Conventional techniques for the preparation/isolation of individual enantiomers include chiral synthesis from a suitable optically pure precursor or resolution of the racemate (or the racemate of a salt or derivative) using, for example, chiral high pressure liquid chromatography (HPLC).

Alternatively, the racemate (or a racemic precursor) may be reacted with a suitable optically active compound, for example, an alcohol, or, in the case where the compound of formula (I) contains an acidic or basic moiety, an acid or base such as tartaric acid or 1-phenylethylamine. The resulting diastereomeric mixture may be separated by chromatography and/or fractional crystallization and one or both of the diastereoisomers converted to the corresponding pure enantiomer(s) by means well known to a skilled person. Chiral compounds of the invention (and chiral precursors thereof) may be obtained in enantiomerically-enriched form using chromatography, typically HPLC, on an asymmetric resin with a mobile phase consisting of a hydrocarbon, typically heptane or hexane, containing from 0 to 50% isopropanol, typically from 2 to 20%, and from 0 to 5% of an alkylamine, typically 0.1% diethylamine. Concentration of the eluate affords the enriched mixture. Mixtures of stereoisomers may be separated by conventional techniques known to those skilled in the art. [see, for example, "Stereochemistry of Organic Compounds" by E L Eliel (Wiley, New York, 1994).]

The present invention includes all pharmaceutically acceptable isotopically- labelled compounds of formula I wherein one or more atoms are replaced by atoms having the same atomic number, but an atomic mass or mass number different from the atomic mass or mass number usually found in nature.

Examples of isotopes suitable for inclusion in the compounds of the invention include isotopes of hydrogen, such as ²H and ³H, carbon, such as ¹¹C, ¹³C and ¹⁴C, chlorine, such as ³⁶CI, fluorine, such as ¹⁸F, iodine, such as ¹²³I and ¹²⁵I₁ nitrogen, such as ¹³N and ¹⁵N, oxygen, such as ¹⁵0, ¹⁷O and ¹⁸O, phosphorus, such as ³²P, and sulfur, such as ³⁵S. Certain isotopically-labelled compounds of formula I, for example, those incorporating a radioactive isotope, are useful in drug and/or substrate tissue distribution studies. The radioactive isotopes tritium, i.e. ³H, and carbon-14, i.e. ¹⁴C, are particularly useful for this purpose in view of their ease of incorporation and ready means of detection. Substitution with heavier isotopes such as deuterium, i.e. ²H, may afford certain therapeutic advantages resulting from greater metabolic stability, for example, increased in vivo half-life or reduced dosage requirements, and hence may be preferred in some circumstances. Substitution with positron emitting isotopes, such as ¹¹C, ¹⁸F, ¹⁵O and ¹³N, can be useful in Positron Emission Topography (PET) studies for examining substrate receptor occupancy. Isotopically-labeled compounds of formula (I) can generally be prepared by conventional techniques known to those skilled in the art or by processes analogous to those described in the accompanying Examples and Preparations using an appropriate isotopically-labeled reagents in place of the non- labeled reagent previously employed.

A preferred embodiment of the present invention are compounds of Formula I as described above wherein X is CR⁴ and Z is S or a pharmaceutically acceptable salt thereof. Another preferred embodiment of the present invention is a compound of Formula I wherein X is N and Z is S or a pharmaceutically acceptable salt thereof. Another preferred embodiment of the present invention is a compound of Formula I wherein X is N and Z is O or a pharmaceutically acceptable salt thereof.

Another preferred embodiment of the present invention are compounds of Formula I wherein X is CR⁴ and Z is S; or X is N and Z is S; or X is N and Z is O; and R² is aryl or heteroaryl, wherein said aryl or heteroaryl is optionally substituted with one to three substituents independently selected from hydroxy, methyl, methoxy, (Ci-

C₆)alkylcarboxamido- or halo; and wherein said (Ci-C₆)alkylcarboxamido- substituent is optionally substituted with one to three fluoro or a pharmaceutically acceptable salt thereof.

Another preferred embodiment of the present invention are compounds of Formula I wherein X is CR⁴ and Z is S; or X is N and Z is S; or X is N and Z is O; and R² is 2-hydroxy-phenyl, 3-hydroxy-pyridin-2-yl or thiazolyl; wherein said 2-hydroxy-phenyl, 3-hydroxy-pyridin-2-yl or thiazolyl is optionally substituted with one fluoro or (Ci- C₆)alkylcarboxamido-; and wherein said (d-C^alkylcarboxamido- substituent is optionally substituted with one to three fluoro or a pharmaceutically acceptable salt thereof.

Another preferred embodiment of the present invention is a compound of Formula I as described in any of the preceding embodiments wherein R¹ is Q-(Cr CiOalkyl-; wherein the (CrC-Oalkyl portion of said Q-(Ci -C-Oalkyl- is optionally substituted with one to three fluoro and Q is phenyl optionally substituted with one or two substituents independently selected from fluoro or methoxy or a pharmaceutically acceptable salt thereof.

Another preferred embodiment of the present invention are compounds of Formula I wherein X is CR⁴ and Z is S; or X is N and Z is S; or X is N and Z is O; R¹ is Q-(Ci-C₄)alkyl-; wherein the (Ci-C₄)alkyl portion of said Q-(Ci-C₄)alkyl- is optionally substituted with one to three fluoro and Q is phenyl optionally substituted with one or two substituents independently selected from fluoro or methoxy; and R² is aryl or heteroaryl, wherein said aryl or heteroaryl is optionally substituted with one to three substituents independently selected from hydroxy, methyl, methoxy, (Cr

C₆)alkylcarboxamido- or halo; and wherein said (CrC₆)alkylcarboxamido- substituent is optionally substituted with one to three fluoro or a pharmaceutically acceptable salt thereof.

Another preferred embodiment of the present invention is a compound of Formula I wherein R¹ is phenethyl or 1-methyl-2-(phenyl)ethyl, wherein said phenethyl or 1-methyl-2-(phenyl)ethyl is optionally substituted on phenyl with one or two halo and optionally substituted on the ethyl or 1 -methylethyl moiety with one to three fluoro; and R² is 2-hydroxy-phenyl or 3-hydroxy-pyridin-2-yl, wherein said 2-hydroxy-phenyl or 3- hydroxy-pyridin-2-yl is optionally substituted with one methyl, methoxy, (Cr C₆)alkylcarboxamido- or fluoro; wherein said (CrC^alkylcarboxamido- substituent is optionally substituted with one to three fluoro or a pharmaceutically acceptable salt thereof.

Another preferred embodiment of the present invention is a compound of Formula I wherein R¹ is phenethyl or 1-methyl-2-(phenyl)ethyl, wherein said phenethyl or 1-methyl-2-(phenyl)ethyl is optionally substituted on phenyl with one or two halo and optionally substituted on the ethyl or 1 -methylethyl moiety with one to three fluoro; and R² is 2-hydroxy-phenyl or 3-hydroxy-pyridin-2-yl, wherein said 2-hydroxy-phenyl or 3- hydroxy-pyridin-2-yl is optionally substituted with one methyl, methoxy, (Cr C₆)alkylcarboxamido- or fluoro; wherein said (Ci-Cejalkylcarboxamido- substituent is optionally substituted with one to three fluoro; R³ is (Ci-C₃)alkyl, Q-(CrC₂)alkyl-, cyano or halo, wherein said (CrC₃)alkyl or Q-(Ci-C₂)alkyl- is optionally substituted with one to three halo; preferably wherein R³ is trifluoromethyl or cyano; and R⁴ is hydrogen or methyl when X is CR⁴ or a pharmaceutically acceptable salt thereof.

Another preferred embodiment of the present invention is a compound of Formula I wherein R³ is trifluoromethyl or cyano or a pharmaceutically acceptable salt thereof. Another preferred embodiment of the present invention is a compound of Formula I wherein R³ is trifluoromethyl or cyano; and R⁴ is hydrogen or methyl when X is CR⁴ or a pharmaceutically acceptable salt thereof.

Another preferred embodiment of the present invention is a compound of Formula I wherein R² is aryl or heteroaryl, wherein said aryl or heteroaryl is optionally substituted with one to three substituents independently selected from hydroxy, methyl, methoxy, (Ci-C₆)alkylcarboxamido or fluoro; wherein said (CrC₆)alkylcarboxamido substituent is optionally substituted with one to three fluoro; R³ is trifluoromethyl or cyano; and R⁴ is hydrogen or methyl when X is CR⁴; or a pharmaceutically acceptable salt thereof.

Another preferred embodiment of the present invention is a compound of Formula I wherein R² is 2-hydroxy-phenyl, 3-hydroxy-pyridin-2-yl or thiazolyl; wherein said 2-hydroxy-phenyl, 3-hydroxy-pyridin-2-yl or thiazolyl is optionally substituted with one substituent selected from methyl, methoxy, (Ci-Cβjalkylcarboxamido- or fluoro; wherein said (Ci-C₆)alkylcarboxamido- substituent is optionally substituted with one to three fluoro; R³ is trifluoromethyl or cyano; and R⁴ is hydrogen or methyl when X is CR⁴; or a pharmaceutically acceptable salt thereof. Yet another preferred embodiment of the present invention is the immediately preceding embodiment wherein R¹ is Q-(Ci- C₄)alkyl-; wherein the (Ci-C₄)alkyl portion of said Q-(Ci -C₄)alkyl- is optionally substituted with one to three fluoro and Q is phenyl optionally substituted with one or two substituents independently selected from fluoro, methyl or methoxy or a pharmaceutically acceptable salt thereof. Another preferred embodiment of the present invention is a compound of

Formula I wherein R¹ is phenethyl or 1 -methyl-2-(phenyl)ethyl, wherein said phenethyl or 1-methyl-2-(phenyl)ethyl is optionally substituted on phenyl with one or two substituents independently selected from methoxy, methyl, fluoro or chloro and optionally substituted on the ethyl or 1-methylethyl moiety with one to three fluoro; R³ is trifluoromethyl or cyano; and R⁴ is hydrogen or methyl when X is CR⁴ or a pharmaceutically acceptable salt thereof.

Another preferred embodiment of the present invention is a compound of Formula I wherein R² is 2-hydroxy-phenyl, 3-hydroxy-pyridin-2-yl or thiazolyl, wherein said 2-hydroxy-phenyl, 3-hydroxy-pyridin-2-yl or thiazolyl is optionally substituted with one or two substituents independently selected from methyl, methoxy, trifluoromethylcarboxamido- or fluoro; R³ is trifluoromethyl or cyano; and R⁴ is hydrogen or methyl when X is CR⁴ or a pharmaceutically acceptable salt thereof. Another preferred embodiment of the present invention is a compound of

Formula I wherein R¹ is phenethyl or 1-methyl-2-(phenyl)ethyl, wherein said phenethyl or 1-methyl-2-(phenyl)ethyl is optionally substituted on phenyl with one or two substituents independently selected from fluoro, methyl or methoxy; R² is 2-hydroxy- phenyl, 3-hydroxy-pyridin-2-yl or thiazolyl wherein said 2-hydroxy-phenyl, 3-hydroxy- pyridin-2-yl or thiazolyl is optionally substituted with one fluoro or (Cr

C₆)alkylcarboxamido-; wherein said (CrC₆)alkylcarboxamido- substituent is optionally substituted with one to three fluoro; R³ is trifluoromethyl or cyano; and R⁴ is hydrogen when X is CR⁴ or a pharmaceutically acceptable salt thereof. Yet another preferred embodiment of the present invention is the immediately preceding embodiment wherein X is N or, alternatively, X is CR⁴ or a pharmaceutically acceptable salt thereof.

Another preferred embodiment of the present invention is a compound of Formula I wherein Q is (C₃-C₇)cycloalkyl; preferably cyclohexyl or a pharmaceutically acceptable salt thereof. Another preferred embodiment of the present invention is a compound of Formula I wherein R² is (C₃-C₇)cycloalkyl; preferably cyclopentyl; or a pharmaceutically acceptable salt thereof.

Another preferred embodiment of the present invention is a compound selected from the group consisting of: 2-Phenyl-5-trifluoromethyl-3-(2-thiazol-4-yl-ethyl)-3H-thieno[2,3-d]pyrimidin-4-one; 2-(2-Hydroxy-phenyl)-5-trifluoromethyl-3-phenethyl-3H-thieno[2,3-d]pyrimidin-4-one; 2-(2-Hydroxy-phenyl)-3-phenethyl-5-phenyl-3H-thieno[2,3-cflpyrimidin-4-one; 2-Cyclopentyl-3-phenethyl-3/-/-thieno[2,3-d]pyrimidin-4-one; 3-[2-(3-Fluoro-phenyl)-ethyl]-2-(2-hydroxy-phenyl)-6-methyl-5-p-tolyl-3H-thieno[2,3- d]pyrimidin-4-one;

6-Benzyl-3-[2-(3-fluoro-phenyl)-ethyl]-2-(2-hydroxy-phenyl)-5-methyl-3H-thieno[2,3- c/Jpyrimidin-4-one; 3-[2-(3-Fluoro-phenyl)-ethyl]-2-(2-hydroxy-phenyl)-5,6-dimethyl-3H-thieno[2,3- c/Jpyrimidin-4-one;

2-Cyclopentyl-3-phenethyl-5-trifluoromethyl-3/-/-thieno[2,3-αf]pyrimidin-4-one;

3-[2-(2-Fluoro-phenyl)-ethyl]-2-(2-hydroxy-phenyl)-5-trifluoromethyl-3H-thieno[2,3- d]pyrimidin-4-one; 2-(2-Hydroxy-pyridin-3-yl)-3-phenethyl-5-trifluoromethyl-3H-thieno[2,3-d]pyrimidin-4- one;

(f?)-2-(3-hydroxypyridin-2-yl)-3-(1-phenylpropan-2-yl)-5-(trifluoromethyl)thienol[2,3- d]pyrinidin-4-(3H)-one;

3-(2-fluorophenethyl)-2-(3-hydroxypyridin-2-yl)-5-(trifluoromethyl)thieno[2,3-d]pyrimidin- 4(3H)-one;

3-(2-methoxyphenethyl)-2-(3-hydroxypyridin-2-yl)-5-(trifluoromethyl)thieno[2,3- d]pyrimidin-4(3H)-one;

3-(2-cyclohexylethyl)-2-(thiazol-4-yl)-5-(trifluoromethyl)thieno[2,3-d]pyrimidin-4(3H)-one;

2-(3-(2-cyclohexylethyl)-4-oxo-5-(trifluoromethyl)-3,4-dihydrothieno[2,3-d]pyrimidin-2- yl)benzonitrile;

3-(2-cyclohexylethyl)-2-(2-hydroxyphenyl)-5-(trifluoromethyl)thieno[2,3-d]pyrimidin-

4(3H)-one;

3-(2-cyclohexylethyl)-2-(3-hydroxypyridin-2-yl)-5-(trifluoromethyl)thieno[2,3-d]pyrimidin-

4(3H)-one; 6-(2-Hydroxy-phenyl)-5-phenethyl-3-trifluoromethyl-5H-isothiazolo[5,4-d]pyrimidin-4- one;

5-[2-(3-Fluoro-phenyl)-ethyl]-6-(2-hydroxy-phenyl)-3-trifluoromethyl-5H-isothiazolo[5,4- d]pyrimidin-4-one;

5-[2-(3-Fluoro-phenyl)-ethyl]-6-(2-hydroxy-phenyl)-3-isopropyl-5H-isothiazolo[5,4- c/Jpyrimidin-4-one;

5-[2-(3-Fluoro-phenyl)-ethyl]-6-(2-hydroxy-phenyl)-3-propylsulfanyl-5/-/-isothiazolo[5,4- cdpyrimidin-4-one; 5-[2-(3-Fluoro-phenyl)-ethyl]-6-(2-hydroxy-phenyl)-3-methyl-5H-isothiazolo[5,4- d]pyrimidin-4-one;

5-[2-(2-Fluoro-phenyl)-ethyl]-6-(2-hydroxy-phenyl)-3-trifluoromethyl-5H-isothiazolo[5,4- d]pyrimidin-4-one; (R)-6-(2-Hydroxyphenyl)-5-(1-phenylpropan-2-yl-3-(trifluoromethyl)isothiazolo[5,4- d]pyrimidin-4(5H)-one;

5-(3,4-Difluorophenethyl)-6-(2-hydroxyphenyl)-3-(trifluoromethyl) isothiazolo[5,4- d]pyrimidin-4(5H)-one;

6-(2-Hydroxyphenyl)-5-phenethyl-3-(trichloromethyl)isothiazolo[5,4-d]pyrimidin-4(5H)- one;

(R)-6-(2-Hydroxyphenyl)-4-oxo-5-(1-phenylpropan-2-yl)- isothiazolo[5,4-d]pyrimidine-3- carbonitrile;

(RJ-e-CS-hydroxypyridin^-yO-δ-CI-phenylpropan^-yO-S-^rifluoromethyOisothiazoloIS^- d]pyrimidin-4(5H)-one; 5-(2-methoxyphenethyl)-6-(3-hydroxypyridin-2-yl)-3-(trifluoromethyl)isothiazolo[5,4- d]pyrimidin-4(5H)-one;

(^-δ^i-cyclohexylpropan^-ylJ-β^S-hydroxypyridin^-yO-S-

(trifluoromethyl)isothiazolo[5,4-d]pyrimidin-4(5H)-one;

5-(2-cyclohexylethyl)-6-(3-hydroxypyridin-2-yl)-3-(trifluoromethyl)isothiazolo[5,4- d]pyrimidin-4(5H)-one;

5-(2-cyclohexylethyl)-6-(thiazol-4-yl)-3-(trifluoromethyl)isothiazolo[5,4-d]pyrimidin-4(5H)- one;

S-CcyclohexylmethyO-β^S-hydroxypyridin^-yO-S-^rifluoromethyOisothiazolotδ^- d]pyrimidin-4(5H)-one; 5-cyclohexyl-6-(3-hydroxypyridin-2-yl)-3-(trifluoromethyl)isothiazolo[5,4-d]pyrimidin-

4(5H)-one;

5-[2-(3-Fluoro-phenyl)-ethyl]-6-(2-hydroxy-phenyl)-3-methyl-5/-/-isoxazolo[5,4- cf]pyrimidin-4-one;

6-(2-Hydroxy-phenyl)-5-phenethyl-3-trifluoromethyl-5/-/-isoxazolo[5,4-c/]pyrimidin-4-one; 5-[2-(3-Fluoro-phenyl)-ethyl]-6-(2-hydroxy-phenyl)-3-trifluoromethyl-5H-isoxazolo[5,4- d]pyrimidin-4-one;

6-(2-Hydroxy-phenyl)-5-((R)-1-methyl-2-phenyl-ethyl)-3-trifluoromethyl-5H- isoxazolo[5,4-d]pyrimidin-4-one; (f?)-N-(2-(4-oxo-5-(1-phenylpropan-2-yl)-3-(trifluoromethyl)-4,5-dihydroisoxazolo[5,4- d]pyrimidin-6-yl)pyridin-3-yl)acetamide;

(/?)-N-(2-(4-oxo-5-(1-phenylpropan-2-yl)-3-(trifluoromethyl)-4,5-dihydroisoxazolo[5,4- d]pyrimidin-6-yl)pyridin-3-yl)isobutyramide; (R)-N-(2-(4-oxo-5-(1-phenylpropan-2-yl)-3-(trifluoromethyl)-4,5-dihydroisoxazolo[5,4- d]pyrimidin-6-yl)pyridin-3-yl)methanesulfonamide;

(/?)-2,2,2-trifluoro-N-(2-(4-oxo-5-(1-phenylpropan-2-yl)-3-(trifluoromethyl)-4,5- dihydroisoxazolo[5,4-d]pyrimidin-6-yl)pyridin-3-yl)acetamide;

(/?)-6-(3-(methylamino)pyridin-2-yl)-5-(1-phenylpropan-2-yl)-3- (trifluoromethyl)isoxazolo[5,4-d]pyrimidin-4(5H)-one;

(RJ-β^S-hydroxypyridin^-yO-δ^i-phenylpropan^-yO-S-CtrifluoromethyOisoxazolofδ^- d]pyrimidin-4(5H)-one; and

5-(2-fluorophenethyl)-6-(3-aminopyridin-2-yl)-3-(trifluoromethyl)isoxazolo[5,4- d]pyrimidin-4(5H)-one or a pharmaceutically acceptable salt thereof. Another embodiment of the present invention is a pharmaceutical composition comprising a compound according to Formula I or pharmaceutically acceptable salt thereof as described in any of the preceding embodiments hereinabove and a pharmaceutically acceptable carrier, adjuvant or diluent.

Another embodiment of the present invention are novel intermediate compounds such as 6-(2-methoxyphenyl)-3-(trifluoromethyl)isothiazolo[5,4-d]pyramid-4(5H)-one; 6-

(2-methoxyphenyl)-5-phenethyl-3-(trifluoromethyl)isothiazolo [5,4-d] pyramid-4-one; (R)- β-CS-nitropyridin^-yO-δ-CI-phenylpropan^-yO-S-^rifluoromethyOisoxazoloIS^- d]pyrimidin-4(5H)-one; (/?)-6-(3-aminopyridin-2-yl)-5-(1-phenylpropan-2-yl)-3-

(trifluoromethyl)isoxazolo[5,4-d]pyrimidin-4(5H)-one; 5-(2-fluorophenethyl)-6-(3- aminopyridin-2-yl)-3-(trifluoromethyl)isoxazolo[5,4-d]pyrimidin-4(5H)-one; 6-(2-

Methoxyphenyl)-3-(trichloromethyl)isothiazolo[5,4-d]pyrimidin-4(5H)-one; 6-(2-

MethoxyphenyO-δ-phenethyl-S-CtrichloromethyOisothiazoloIS^-dJ pyrimidin^δHJ-one;

(R)-Methyl 6-(2-methoxyphenyl)-4-oxo-5-(1-phenylpropan-2-yl)-isothiazolo[5,4- d]pyrimidine-3-carboxylate; (R)-6-(2-Methoxyphenyl)-4-oxo-5-(1-phenylpropan-2-yl)- isothiazolo[5,4-d]pyrimidine-3-carboxamide; (R)-6-(2-Methoxyphenyl)-4-oxo-5-(1 - phenylpropan-2-yl)-isothiazolo[5,4-d]pyrimidine-3-carbonitrile; and 2-(2-Hydroxy- phenyl)-5-methyl-3-phenethyl-3H-thieno[2,3-d]pyrimidin-4-one or a pharmaceutically acceptable salt thereof. Another embodiment of the present invention is a method of treating a disease or disorder characterized by abnormal bone or mineral homeostasis which comprises administering to a patient in need of treatment thereof a therapeutically effective amount of a compound according to Formula I or a pharmaceutically acceptable salt thereof or pharmaceutical composition thereof as described in any of the preceding embodiments hereinabove. A preferred embodiment of the present invention is the method according to the preceding embodiment wherein the disease or disorder characterized by abnormal bone or mineral homeostasis is selected from the group consisting of osteoporosis, osteopenia, periodontal disease, Paget's disease, bone fracture, osteoarthritis, rheumatoid arthritis, and humoral hypercalcemia of malignancy. Yet another preferred embodiment is the method according to the preceding embodiment wherein the disease or disorder characterized by abnormal bone or mineral homeostasis is osteoporosis.

The following reaction schemes, Reaction Schemes 1-4, depict methods of synthesis for compounds of formula I. In the following general methods for preparation of the compounds of formula I the variables R¹, R² and R³, are as previously defined for a compound of the formula I unless otherwise stated. The Reaction Schemes herein described are intended to provide a general description of the methodology employed in the preparation of many of the Examples given. However, it will be evident from the detailed descriptions given in the Experimental section that the modes of preparation employed extend further than the general procedures described herein. In particular, it is noted that the compounds prepared according to these Schemes may be modified further to provide new Examples within the scope of this invention. The reagents and intermediates used in the following examples are either commercially available or can be prepared according to standard literature procedures by those skilled in the art of organic synthesis. General Synthesis

The compounds of the present invention may be prepared by a variety of processes as represented by the reaction schemes provided below. The reaction schemes represent processes that can be employed to prepare compounds of Formula I and are not to be construed as a limitation of the invention. The starting materials employed in the general syntheses may be commercially available or obtained by conventional methods known to those skilled in the art. Reaction Scheme 1

I

Reaction Scheme 1 , depicted above, provides a method of preparing compounds of Formula I. In Reaction Scheme 1 , for the compounds of Formula IV, III or II, the moiety R² represents either the group R², a protected version of group R² or a moiety that can be further derivatized to provide group R². It is to be understood that when R² represents the group R² further deprotection or derivatization is not necessary to provide a compound of Formula I. Step 1- Cvclization Reaction The initial cyclization reaction is carried out by combining an appropriate amide substituted heterocyclic amine of Formula V (1.0 equivalent) with a slight excess of an appropriate aldehyde, R²CHO, of Formula IV (1.05 equivalent) in a solution of p- toluenesulfonic acid in glacial acetic acid (0.05 equivalents of p-TsOH). Typically, to the compound of Formula V (1.0 equivalent) is added a 0.018M solution of p- toluenesulfonic acid in glacial acetic acid (0.05 equivalent of p-TsOH) in an appropriate reaction vessel. Following this, an appropriate aldehyde of Formula IV (1.05 equivalents) is added. The reaction mixture is then heated with agitation, preferably at 95 ⁰C, for a period of 1 to 24 hours, preferably for a period of 8 to 10 hours. Following the heating period, the reaction mixture is allowed to continue to agitate at ambient temperature until assay and work up. The reaction mixture is combined with EtOAc, and the reaction mixture is washed twice with portions of 2N NaOH, such that the final pH of the aqueous wash is approximately 12. The neutralized reaction is then washed once each with 1/2 saturated NaCI, water and brine. The organic layer is filtered and concentrated in vacuo to dryness. The resulting crude reaction product of Formula III is carried on to the alkylation step. Step 2 - Alkylation Step

The crude compound of Formula III, as obtained in the preceding step, is dissolved in an appropriate solvent, preferably such that the concentration is approximately 0.1 M. Appropriate solvents are reaction inert and include aliphatic hydrocarbons such as pentane, hexane, heptane or petroleum ether; aromatic hydrocarbons such as benzene, toluene, o-dichlorobenzene, nitrobenzene, pyridine or xylene; halogenated hydrocarbons such as dichloromethane, chloroform, carbon tetrachloride or 1,2-dichloroethane; ethers such as diethyl ether, diisopropyl ether, tetrahydrofuran or 1 ,4-dioxane; dimethylformamide or dimethylsulfoxide. To this solution is added an appropriate base, e.g. an alkali or alkaline earth metal hydroxide, alkoxide, carbonate, halide or hydride, such as sodium hydroxide, potassium hydroxide, sodium methoxide, sodium ethoxide, potassium tert-butoxide, sodium carbonate, potassium carbonate, potassium fluoride, sodium hydride or potassium hydride, or an amine such as triethylamine, tributylamine, diisopropylethylamine, pyridine or dimethylaminopyridine. For example, aqueous potassium carbonate (such that approximately 10% of the total volume is the aqueous potassium carbonate solution) can be employed. The resulting mixture is then heated, preferably to 80 ⁰C, with agitation. An appropriate amount of the compound of formula R¹LG, typically 1.0 to 2.0 equivalents, wherein LG represents an appropriate leaving group, either neat or in solution, is then added to the warm reaction mixture while agitation is continued. Appropriate leaving groups include halides such as chloride, bromide or iodide or tosylate or trifluoromethanesulfonate. The agitation rate is then increased and the reaction is heated for a period of 1 to 48 hours, followed by continued agitation at RT until work up. The crude reaction mixture is concentrated in vacuo and the residue is taken up in an appropriate organic solvent such as EtOAc. The resulting mixture is washed with water and then brine. The organic layer is filtered and concentrated in vacuo to dryness to provide the compound of Formula II. When the group R² represents group R² the compound of Formula Il is equivalent to a compound of Formula I. Step 3 - Deprotection or Derivatization (if necessary) Deprotection or Derivatization of the group R² to provide group R²

When R² represents a protected version of the group R² it can be deprotected by conventional methods known to those skilled in the art. Suitable protecting groups and methods for their removal are illustrated in Protective Groups in Organic Synthesis, 3^rd Ed., Theodora W. Greene and Peter G. M. Wuts (John Wiley & Sons, 1999). For example, the group R² in the compound of Formula Il may contain a protected hydroxy group, such as a benzyloxy or methoxy group, which can be subsequently deprotected by known methods to provide a hydroxy moiety within the group R² in the compound of Formula I. In cases where the compound of formula Il contains a suitable methoxy moiety, the compound of Formula Il is dissolved in a suitable solvent such as methylene chloride at a temperature between -78 ⁰C to 10 ⁰C followed by the addition of boron trichloride or boron tribromide. The reaction mixture is stirred at 10 ⁰C to 50 ⁰C for 1 to 24 hours to provide the desired deprotected compound of Formula I. Similarly, compounds of formula Il containing a suitable benzyloxy moiety can be deprotected to provide compounds of formula I by treatment with HCI/acetic acid or by hydrogenation, such as H-cube hydrogenation (Pd/C cartridge), carried out at ambient temperature using methanol as solvent. R² may represent a moiety that requires further derivatization to be converted into group R² in a compound of Formula I. For example, the group R² in the compound of Formula Il may contain a primary amine group which is further derivatized by methods known in the art to provide an alkylamino, amide, carbamate or sulfonamide group within R² in the compound of Formula I. Reaction of a primary amine within group R² , with an appropriate carboxylic acid in the presence or absence of a peptide coupling reagent in a reaction inert solvent provides appropriate amide derivatives. Suitable coupling reagents are those typically employed in peptide synthesis such as 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC); 2-bromo-1-ethylpyridinium tetrafluoroborate (BEP); benzotriazol-1- yloxy-tris(dimethylamino)phosphonium hexafluorophosphate (BOP); 2-chloro-1 ,3- dimethylimidazolinium chloride; N.N'-carbonyldiimidazole (CDI); O-(BenzotriazoM-yl)- Λ/,Λ/,Λ/',Λ/'-tetramethyluronium hexafluorophosphate (HBTU) or dicyclohexylcarbodiimide (DCC). The reaction can optionally be carried out in the presence of a base such as hydroxy benzotriazole (HOBT); N,N-diisopropylethylamine; N-methylmorpholine or triethylamine under standard peptide coupling conditions to provide the desired amide compounds. The peptide coupling reaction is typically carried out in an appropriate solvent such as acetone; DMF; NMP; sulfolane; DMSO; 2-butanone; acetonitrile; halogenated hydrocarbons such as DCM, dichloroethane or chloroform; or ethers such as THF or 1 ,4-dioxane. The reaction is typically carried out at a temperature of from -20 ⁰C to 100 ⁰C, more preferably from about 0 ⁰C to 60 ⁰C₁ typically for a period of 5 minutes to 72 hours, preferably a period of 30 minutes to 24 hours.

Amide derivatives can also be prepared by reacting an amine, when present in group R² , with an appropriate acid halide or anhydride under standard conditions known to those skilled in the art. Reaction of the amine within group R² with an appropriate carbamoyl chloride or sulfonyl chloride under standard conditions leads to carbamate or sulfonamide derivatives, respectively. Acid chlorides that can be employed can be prepared, for example, by reacting an appropriate acid with a chlorinating reagent such as oxalyl chloride, phosphorus oxychloride or thionyl chloride.

Reaction of an amine group in R² with an appropriate aldehyde under reductive amination conditions well known to those skilled in the art, and exemplified by Pae et al. Bioorg. Med. Chem. Lett. 1999, 9, 2679, provides alkylamino derivatives within Formula I. Representative reductive amination conditions typically employ treating the amine with an appropriate aldehyde followed by reduction with an appropriate reducing agent, such as sodium cyanoborohydride or triacetoxyborohydride in an appropriate solvent such as dichloroethane. Alkylamino derivatives can also be accessed by direct alkylation of the amine in group R² with an appropriate alkyl halide or alkyl sulfonate, many of which are commercially available. Alkyl halides or alkyl sulfonates can also be easily synthesized according to the methods of Fries et al., J. Med. Chem. 1979, 22, 356; Nordlander et al., Zh. Org. Khim. 1996, 32(12), 1883; or Geminer et al., Bioorg. Med. Chem. Lett. 1993, 3(8), 1477, or by numerous other methods that are well known to those skilled in the art.

Oxidation Step (if necessary) In the synthesis of the Formula I compounds as depicted above in Reaction

Scheme 1 the cyclization reaction of compound V and IV, in certain cases, does not undergo air oxidation under standard reaction conditions and results in dihydro analogs of intermediate compounds of Formulae III and II. The resulting dihydo analog of intermediate of Formula Il can be oxidized as depicted below to provide the compound of Formula II, which can be deprotected or derivatized, if necessary, to provide the compound of Formula I. The oxidation can be carried out using

standard oxidation conditions. Typically, the dihydro analog of the compound of Formula Il is treated with an appropriate oxidizing agent in an appropriate organic solvent at a temperature from 0 ⁰C to 150 ⁰C for a period of 30 minutes to 24 hours to provide the compound of Formula II. Appropriate oxidizing agents include manganese dioxide, potassium permanganate or dichlorodicyanobenzoquinone and an appropriate organic solvent such as DMF can be employed. The resulting compound of Formula Il can then be deprotected or derivatized, if necessary, to provide the compound of Formula I. This oxidation step can be carried out, as required, for dihydro intermediate compounds prepared by any of reaction schemes 1-4 as described herein.

Reaction Scheme 1A

Reaction Scheme 1A, above, depicts the preparation of certain compounds within Formula I of the Formula IA wherein R² is 2-hydroxyphenyl.

Step 1- Cvclization Reaction

The starting material of Formula V is weighed out (0.3 mmol) into a reaction vessel and to the vessel is added a 0.018M solution of p-toluenesulfonic acid in glacial acetic acid. The appropriate amount of solution is added to the reaction such that 0.05eq of p-toluenesulfonic acid is delivered, (~840ul). Anisaldehyde, ~40ul (1.05 equiv.), is added neat to the reaction vessel. The reaction mixture is agitated on a heated shaker plate, at 95 ⁰C for 9 hours. Following the heating period, the reaction is allowed to continue to agitate at RT until assay and work up. The reaction is combined with 2 ml_ of EtOAc, then is washed twice with 2.5 ml_ portions of 2N NaOH, with the final pH of the wash being approximately 12. Following each wash the aqueous layer is decanted using a syringe. The organic layer is then washed once with 1/2 saturated NaCI, approximately 1 mL of water and 1 ml_ of brine. The organic layer is decanted and passed through an extract filter cartridge. The collected filtrate is evaporated to dryness on a Genevac, at EtOAc settings. The crude reaction product of Formula Ilia is carried on to the next alkylation step. Step 2 - Alkylation with 3-fluorophenethylbromide

The crude compound of Formula IHa is combined with an appropriate amount of DMF, vortexed, and then an appropriate amount of the potassium carbonate solution is added such that the overall concentration is approximately 0.1 M and 10% of the total volume is the aqueous potassium carbonate. The reaction mixture is then placed on a heated 80 ⁰C shaker plate and allowed to warm over approximately 15 minutes. The appropriate amount of the 3-fluorophenethyl bromide solution was then added to the warm reaction mixture while gentle mixing is continued. It is to be understood that other appropriate alkylating agents of formula R¹LG can be used in place of the 3- fluorophenethyl bromide to provide corresponding analogs. The agitation rate is then increased and the reaction mixture is allowed to continue heating for 31 hours, followed by continued stirring at RT until work up. The crude reaction solution is first placed in the Genevac the DMF is removed in vacuo. To the residue is added 2 mL of EtOAc and 2 mL of water. The aqueous layer is decanted. To the organic layer is added 2 mL of brine. The organic layer is separated, passed through an extraction filter, and the filtrate is collected and concentrated to dryness in vacuo. Toluene (2 mL) is then added to the residue which is then concentrated in vacuo to provide crude compound of Formula Ha. Step 3 - Deprotection of Methoxy to Hydroxy

The crude compound of Formula Ha obtained in previous step is dissolved in 500ul-1000ul of dry DCM, the reaction vessel is capped and purged with nitrogen.

Approx 2.4 mL-3 mL of boron trichloride, BCI₃, is added to the reaction vessel via a gas tight syringe. The reaction mixture is placed on a shaker plate and allowed to agitate at RT. The reaction is quenched by adding 1.5 mL of water, quickly recapping, shaking and carefully venting by loosening the cap. Pressure build-up subsides within approximately 1 minute. The quenched reaction mixture can form emulsions, with only minor separation of the organic layer. The reaction is filtered through approx 500 mg of celite. The filtrate is collected into 13x125 test tubes; the organic layer is decanted into tared Arqule vials for evaporation. Following evaporation the net weight is obtained; the residue is then dissolved in approx 1 ml_ of DMSO. The dissolved residue is then analyzed and purified. Typically the residue is purified by chromatography, such as reverse phase HPLC using a C-18 column and gradient elution with a mixed aqueous/organic solution as the mobile phase or by silica gel chromatography.

Reaction Scheme 2

deprotect

(

Reaction Scheme 2, depicted above, provides another process for synthesizing compounds of Formula I. In Reaction Scheme 2, for the compounds of Formula R²C(O)LG, Vl or II, the moiety R² represents either the group R², a protected version of group R² or a moiety that can be further derivatized to provide group R². It is to be understood that when R² represents the group R² further deprotection or derivatization is not necessary to provide a compound of Formula I.

The 2-amino-1 -carboxylic acid ester substituted heterocycle of Formula VII is dissolved in an appropriate anhydrous solvent such as pyridine. The group R in the compound of Formula VII typically represents a lower alkyl group, preferably methyl. To this solution, triphenylphosphite and the compound of Formula R² C(O)LG is added. The moiety LG in the compound R²C(O)LG represents an appropriate leaving group, typically chloride, such that R² C(O)LG is an appropriate acid chloride. The reaction mixture is typically heated, preferably in a microwave, at a temperature between 200 ⁰C to 250 ⁰C for 5 to 25 minutes, preferably 10 minutes, to afford the compound of Formula Vl. To this reaction mixture is added the amine R¹NH₂ and the resulting mixture is heated, typically in a microwave, typically at a temperature between 200⁰C to 250 ⁰C for 5 to 25 minutes, preferably 15 minutes to afford the desired compound of Formula II. If necessary, the compound of Formula Il is deprotected or derivatized as described previously for Reaction Scheme 1. The compound of Formula I, thus obtained, is typically purified by silica gel column chromatography. '

Reaction Scheme 3, depicted above, provides another process for synthesizing compounds of Formula I. In Reaction Scheme 3, for the compounds of Formula R²CH(OMe)OH or R²CHO, VIII or II, the moiety R^2' represents either the group R², a protected version of group R² or a moiety that can be further derivatized to provide group R². It is to be understood that when R² represents the group R² further deprotection or derivatization is not necessary to provide a compound of Formula I. A solution of an appropriate amine of Formula R¹NH2 in an appropriate solvent such as toluene is treated with trimethyl aluminum at approximately 0 ⁰C. The resulting mixture is then stirred at ambient temperature for approximately 1 to 4 hours. The 2- amino-1-carboxylic acid ester substituted heterocycle of Formula VII is then added. The group R in the compound of Formula VII typically represents a lower alkyl group, preferably methyl. The reaction mixture is then heated, typically at reflux, for a period of 1 to 24 hours, preferably 12 hours. The reaction mixture is allowed to cool, then quenched with a saturated solution of potassium sodium tartrate to break aluminum salts, and extracted with ethyl acetate. The organic layer is washed with H₂O, brine, dried over Na₂SO₄, concentrated in vacuo and purified by silica gel chromatography to provide the compound of Formula VIII. The compound of Formula VIII and the compound of Formula R² CH(OMe)OH or R² CHO in an appropriate solvent, such as xylene, and in the presence of p-toluene sulfonic acid is heated, typically at 150 ⁰C for a period of 1 hour to 1 week. The reaction mixture is then concentrated in vacuo and the residue is purified, typically by silica gel column chromatography, to provide the compound of Formula II. The compound of Formula Il can then be deprotected or derivatized, if necessary, to provide compounds of Formula I. Reaction Scheme 4

reduce

Reaction Scheme 4, above, depicts the preparation of certain compounds of Formula Ib according to the procedures as generally described above for Reaction Scheme 3. The compound of Formula VII is reacted with the amine R¹NH₂ in the presence of trimethyl aluminum to provide the amide compound of Formula VIII. The amide of formula VIII is then reacted with the nitropyridine derivative shown in the presence of p-toluene sulfonic acid to provide the compound of Formula Hc. The nitro group in the compound of Formula Hc is then reduced using an appropriate reducing agent, such as Tin(ll)chloride to provide the amino derivative of Formula lib. The amino compound of Formula Hb can then be derivatized, as described above for Reaction Scheme 1 , to provide the corresponding alkylamino, amide, carbamate or sulfonamide derivatives of Formula Ib (where RNH represents (Ci-C₆)alkylNH, (Ci-C₆)alkylC(O)NH, (C_rC₆)alkylOC(O)NH or (Ci-C₆)alkylSO₂NH).

The term "patient in need of treatment thereof means humans and other animals who have or are at risk of having a disease or disorder characterized by abnormal bone or mineral homeostasis. The "patient in need of treatment thereof may have or be at risk of having a disease or disorder characterized by abnormal bone or mineral homeostasis selected from the group consisting of osteoporosis, osteopenia, periodontal disease, Paget's disease, bone fracture, osteoarthritis, rheumatoid arthritis, and humoral hypercalcemia of malignancy. As certain of the conditions being treated have a higher incidence in females a preferred patient is a female, and particularly a postmenopausal female human. The term "treating", "treat" or "treatment" as used herein includes preventative (e.g., prophylactic), palliative, adjuvant and curative treatment. For example, the treatment of osteoporosis, as used herein means that a patient having osteoporosis or at risk of having osteoporosis can be treated according to the methods described herein. For patients undergoing preventative treatment, a resulting reduction in the incidence of the disease state being preventively treated is the measurable outcome of the preventative treatment.

The present invention provides methods of treating osteopenia and osteoporosis by administering to a patient in need thereof a therapeutically effective amount of a compound of formula I. Osteopenia is a thinning of the bones, but less than is seen with osteoporosis and is the stage before true osteoporosis. The World Health Organization has developed diagnostic categories based on bone mass density (BMD) to indicate if a person has normal bones, has osteopenia or has osteoporosis. Normal bone density is within one standard deviation (+1 or -1) of the young adult mean bone density. Osteopenia (low bone mass) is defined as bone density of 1 to 2.5 standard deviations below the young adult mean (-1 to -2.5), and osteoporosis is defined as a bone density that is 2.5 standard deviations or more below the young adult mean (>- 2.5).

The present invention provides methods of treating bone fractures by administering to a patient in need thereof a therapeutically effective amount of a compound of formula I. Bone fractures can be a fracture to any bone in the body, and hip fracture being of particular concern. Hip fracture has a significant impact on medical resources and patient morbidity and mortality. Few patients admitted with a hip fracture are considered for prophylactic measures aimed at the reduction of further fracture risk. Currently, 10-13% of patients will later sustain a second hip fracture. Of patients who suffered a second hip fracture, fewer patients maintained their ability to walk independently after the second fracture than did so after the first (53 and 91% respectively, P<0.0005). Pearse E.O. et al., Injury. 2003, 34(7), 518-521. Following second hip fracture, patients' level of mobility determined their future social independence. Older patients and those with a history of multiple falls had a shorter time interval between fractures. Second hip fracture has a significant further impact on patients' mobility and social independence. It is therefore desirable to have new methods for the treatment of bone fractures including hip fracture. The compounds of Formula I can be administered together with additional agents which are useful for treating a disease or disorder characterized by abnormal bone or mineral homeostasis. Particularly contemplated additional agents include calcium receptor antagonists other than those of Formula I, selective estrogen receptor modulators (SERMs), bisphosphonates, parathyroid hormone (PTH) and fragments and analogues thereof, estrogens, calcitonins, synthetic steroids, synthetic isoflavones, vitamin D analogues, vitamin K analogues, strontium salts, cathepsin K inhibitors, α_vβ₃ integrin (vitronectin) antagonists, prostaglandin (PGE2) receptor agonists and receptor activator of nuclear factor KB ligand (RANKL) inhibitors. Additional calcium receptor antagonists that can be used together with compounds of Formula I in the methods and compositions of this invention include those described in PCT International Publication Nos. WO 93/04373; WO 94/18959; WO 95/11211 ; WO 97/37967; WO 98/44925; WO 98/45255; WO 99/51241 ; WO 99/51569; WO 00/45816; WO 02/14259; WO 02/38106; WO 2004/041755; and WO 2005/030746; Nemeth, E.F.; Journal of Molecular Endocrinology (2002) 29, 15-21 ; Kessler, A. et al.; ChemBioChem (2004) 5, 1131; Steddon, SJ. et al.; Lancet (2005) 365, 2237-2239; and Shcherbakova, I.; et al.; Bioorganic & Medicinal Chemistry Letters (2005) 15, 1557-1560. Specific calcilytic compounds that can be used together with compounds of Formula I in the methods and compositions of this invention include NPS-2143 and 423562.

SERMs that can be used together with compounds of Formula I in the methods and compositions of this invention include, but are not limited to, lasofoxifene (Oporia®), raloxifene (Evista®), arzoxifene, bazedoxifene, ospemifene, Chiesi's CHF-4227 and Prostrakan's PSK-3471. Bisphosphonates that can be used together with compounds of Formula I in the methods and compositions of this invention include, but are not limited to, tiludronate (Skelid®), clondronate (Bonefos®), etidronate (Didronel®), alendronate (Fosamax®), risedronate (Actonel®), ibandronate (Boniva®), zoledronate (Zometa®), minodronate (Onobis®), neridronate and pamidronate.

In humans, PTH is an 84 amino acid polypeptide produced by the parathyroid gland that controls serum calcium levels through its action on various cells. Several N-terminal amino acids fragments of PTH₁ including the 1-31 , 1-34 and 1-38 fragments (PTH-related proteins; "PTHrP") are considered biologically equivalent to the full length hormone. Parathyroid hormone (PTH) and fragments and analogues thereof that can be used together with compounds of Formula I in the methods and compositions of this invention include, but are not limited to, the full length PTH (such as PTH 1 -84, Preos®/Preotact®, Unigene's 768974, Bone Medical's BN-003), the 1-31 (such as Zelos Therapeutics' Ostabolin-C), 1-34 (such as teriparatide, Forteo®, or Ipsen's BIM- 44058) or 1 -38 fragments.

Estrogens that can be used together with compounds of Formula I in the methods and compositions of this invention include, but are not limited to, estradiol, conjugated equine estrogens (Wyeth's Premarin®) or other estrogens.

Calcitonin is a 32 amino-acid peptide hormone produced by the thyroid gland which inhibits osteoclast activity by binding to calcitonin receptors on the surface of those cells. Calcitonins that can be used together with compounds of Formula I in the methods and compositions of this invention include, but are not limited to, human calcitonin or salmon or eel calcitonins. The calcitonins may be used as injectable or intranasal formulations such as Miacalcin®, Miacalcic®, Calcitonia®, Fortical® or Elcitonin® or as oral formulations such as Novartis' SMC-021 , Bone Medical's BN-002 (Capsitonin®) or Nobex's NCT-025 (Oratonin®).

Synthetic steroids that can be used together with compounds of Formula I in the methods and compositions of this invention include, but are not limited to, mixed estrogen and progesterone agonists such as tibolone which is marketed as Livial®. Synthetic isoflavones are chemically synthesized derivatives of plant isoflavones, such as phytoestrogens extracted from soy products. A synthetic isoflavone that can be used together with compounds of Formula I in the methods and compositions of this invention includes, but is not limited to, ipraflavone which is marketed by Takeda as Iprosten® and Osten®. Vitamin D analogues are compounds that act by binding to the nuclear vitamin D receptor in osteoblasts. Vitamin O analogues that can be used together with compounds of Formula I in the methods and compositions of this invention include, but are not limited to, Chugai's ED-71 and Deltanoid's 2MD.

A strontium salt that can be used together with compounds of Formula I in the methods and compositions of this invention includes, but is not limited to, strontium ranelate (Servier's Protelos®). Cathepsin K inhibitors that can be used together with compounds of Formula I in the methods and compositions of this invention include, but are not limited to, Novartis's AAE-581 , balicatib, GlaxoSmithKline's SB-462795 and Merck's c-3578. An α_vβ₃ integrin (vitronectin) antagonist that can be used together with compounds of Formula I in the methods and compositions of this invention includes, but is not limited to, Merck's MRL-123.

Prostaglandin E2 (PGE2) receptor agonists that can be used together with compounds of Formula I in the methods and compositions of this invention include, but are not limited to, PGE2 subtype 2 (EP2) receptor agonists, such as (3-{[4-Tert-butyl- benzyl)-(pyridine-3-sulfonyl)-amino]-methyl}-phenoxy)-acetic acid, or a pharmaceutically acceptable salt thereof or PGE2 subtype 4 (EP4) receptor agonists, such as ONO-4819. A receptor activator of nuclear factor KB ligand (RANKL) inhibitor that can be used together with compounds of Formula I in the methods and compositions of this invention includes, but is not limited to, Amgen's RANKL antibody AMG-162.

Specific combinations of particular interest include compounds of Formula I and lasofoxifene or compounds of Formula I and (3-{[4-Tert-butyl-benzyl)-(pyridine-3- sulfonyl)-amino]-methyl}-phenoxy)-acetic acid, or a pharmaceutically acceptable salt thereof.

Compounds of the invention intended for pharmaceutical use may be administered as crystalline or amorphous products. The compounds may be obtained, for example, as solid plugs, powders, or films by methods such as precipitation, crystallization, freeze drying, spray drying, or evaporative drying. Microwave or radio frequency drying may be used for this purpose.

For the above-mentioned therapeutic uses, the dosage administered will, of course, vary with the compound employed, the mode of administration, the treatment desired and the disorder indicated. The total daily dosage of the compound of formula l/salt/solvate (active ingredient) will, generally, be in the range from 1 mg to 1 gram, preferably 1 mg to 250 mg, more preferably 10 mg to 100 mg. The total daily dose may be administered in single or divided doses. The present invention also encompasses sustained release compositions.

The pharmaceutical composition may, for example, be in a form suitable for oral administration as a tablet, capsule, pill, powder, sustained release formulations, solution, suspension, for parenteral injection as a sterile solution, suspension or emulsion, for topical administration as an ointment or cream or for rectal administration as a suppository. The pharmaceutical composition may be in unit dosage forms suitable for single administration of precise dosages. The pharmaceutical composition will include a conventional pharmaceutical carrier or excipient and a compound according to the invention as an active ingredient. In addition, it may include other medicinal or pharmaceutical agents, carriers, adjuvants, etc. The dissolution rate of poorly water- soluble compounds may be enhanced by the use of a spray-dried dispersion, such as 5 those described by Takeuchi, H., et al. in "Enhancement of the dissolution rate of a poorly water-soluble drug (tolbutamide) by a spray-drying solvent depostion method and disintegrants" J. Pharm. Pharmacol.. 39, 769-773 (1987). In cases where the compound of Formula I has poor water solubility a preferred embodiment of the pharmaceutical composition may comprise a spray dried dispersion of the compound of

10 Formula I.

Exemplary parenteral administration forms include solutions or suspensions of active compounds in sterile aqueous solutions, for example, aqueous propylene glycol or dextrose solutions. Such dosage forms can be suitably buffered, if desired.

Suitable pharmaceutical carriers include inert diluents or fillers, water and various

15 organic solvents. The pharmaceutical compositions may, if desired, contain additional ingredients such as flavorings, binders, excipients and the like. Thus for oral administration, tablets containing various excipients, such as citric acid may be employed together with various disintegrants such as starch, alginic acid and certain complex silicates and with binding agents such as sucrose, gelatin and acacia. Additionally,

>0 lubricating agents such as magnesium stearate, sodium lauryl sulfate and talc are often useful for tableting purposes. Solid compositions of a similar type may also be employed in soft and hard filled gelatin capsules. Preferred materials, therefor, include lactose or milk sugar and high molecular weight polyethylene glycols. When aqueous suspensions or elixirs are desired for oral administration the active compound therein may be

»5 combined with various sweetening or flavoring agents, coloring matters or dyes and, if desired, emulsifying agents or suspending agents, together with diluents such as water, ethanol, propylene glycol, glycerin, or combinations thereof. Methods of preparing various pharmaceutical compositions with a specific amount of active compound are known, or will be apparent, to those skilled in this art. For examples, see Remington's

10 Pharmaceutical Sciences. Mack Publishing Company, Easter, Pa., 15th Edition (1975).

Dosage regimens may be adjusted to provide the optimum desired response. For example, a single bolus may be administered, several divided doses may be administered overtime or the dose may be proportionally reduced or increased as indicated by the exigencies of the therapeutic situation. It is especially advantageous to formulate parenteral compositions in dosage unit form for ease of administration and uniformity of dosage. Dosage unit form, as used herein, refers to physically discrete units suited as unitary dosages for the mammalian subjects to be treated; each unit containing a predetermined quantity of active compound calculated to produce the desired therapeutic effect in association with the required pharmaceutical carrier. The specification for the dosage unit forms of the invention are dictated by and directly dependent on (a) the unique characteristics of the chemotherapeutic agent and the particular therapeutic or prophylactic effect to be achieved, and (b) the limitations inherent in the art of compounding such an active compound for the treatment of sensitivity in individuals. Thus, the skilled artisan would appreciate, based upon the disclosure provided herein, that the dose and dosing regimen is adjusted in accordance with methods well-known in the therapeutic arts. That is, the maximum tolerable dose can be readily established, and the effective amount providing a detectable therapeutic benefit to a patient may also be determined, as can the temporal requirements for administering each agent to provide a detectable therapeutic benefit to the patient. Accordingly, while certain dose and administration regimens are exemplified herein, these examples in no way limit the dose and administration regimen that may be provided to a patient in practicing the present invention. It is to be noted that dosage values may vary with the type and severity of the condition to be alleviated, and may include single or multiple doses. It is to be further understood that for any particular subject, specific dosage regimens should be adjusted over time according to the individual need and the professional judgment of the person administering or supervising the administration of the compositions, and that dosage ranges set forth herein are exemplary only and are not intended to limit the scope or practice of the claimed composition. For example, doses may be adjusted based on pharmacokinetic or pharmacodynamic parameters, which may include clinical effects such as toxic effects and/or laboratory values. Thus, the present invention encompasses intra-patient dose-escalation as determined by the skilled artisan. Determining appropriate dosages and regiments for administration of the chemotherapeutic agent are well-known in the relevant art and would be understood to be encompassed by the skilled artisan once provided the teachings disclosed herein. A pharmaceutical composition of the invention may be prepared, packaged, or sold in bulk, as a single unit dose, or as a plurality of single unit doses. As used herein, a "unit dose" is discrete amount of the pharmaceutical composition comprising a predetermined amount of the active ingredient. The amount of the active ingredient is generally equal to the dosage of the active ingredient which would be administered to a subject or a convenient fraction of such a dosage such as, for example, one-half or one- third of such a dosage.

The relative amounts of the active ingredient, the pharmaceutically acceptable carrier, and any additional ingredients in a pharmaceutical composition of the invention will vary, depending upon the identity, size, and condition of the subject treated and further depending upon the route by which the composition is to be administered. By way of example, the composition may comprise between 0.1% and 100% (w/w) active ingredient.

In addition to the active ingredient, a pharmaceutical composition of the invention may further comprise one or more additional pharmaceutically active agents. Particularly contemplated additional agents include selective estrogen receptor modulators (SERMs), bisphosphonates, parathyroid hormone (PTH) and fragments and analogues thereof, estrogens, calcitonins, synthetic steroids, synthetic isoflavones, vitamin D analogues, vitamin K analogues, strontium salts, cathepsin K inhibitors, α_vβ₃ integrin (vitronectin) antagonists, prostaglandin (PGE2) receptor agonists and receptor activator of nuclear factor KB ligand (RANKL) inhibitors, such as those described hereinabove.

Controlled- or sustained-release formulations of a pharmaceutical composition of the invention may be made using conventional technology. As used herein, "parenteral administration" of a pharmaceutical composition includes any route of administration characterized by physical breaching of a tissue of a subject and administration of the pharmaceutical composition through the breach in the tissue. Parenteral administration thus includes, but is not limited to, administration of a pharmaceutical composition by injection of the composition, by application of the composition through a surgical incision, by application of the composition through a tissue-penetrating non-surgical wound, and the like. In particular, parenteral administration is contemplated to include, but is not limited to, subcutaneous, intraperitoneal, intramuscular, intrasternal injection, and kidney dialytic infusion techniques.

Formulations of a pharmaceutical composition suitable for parenteral administration comprise the active ingredient combined with a pharmaceutically acceptable carrier, such as sterile water or sterile isotonic saline. Such formulations may be prepared, packaged, or sold in a form suitable for bolus administration or for continuous administration. Injectable formulations may be prepared, packaged, or sold in unit dosage form, such as in ampules or in multi-dose containers containing a preservative. Formulations for parenteral administration include, but are not limited to, suspensions, solutions, emulsions in oily or aqueous vehicles, pastes, and implantable sustained-release or biodegradable formulations as discussed below. Such formulations may further comprise one or more additional ingredients including, but not limited to, suspending, stabilizing, or dispersing agents. In one embodiment of a formulation for parenteral administration, the active ingredient is provided in dry (i.e. powder or granular) form for reconstitution with a suitable vehicle (e.g. sterile pyrogen-free water) prior to parenteral administration of the reconstituted composition.

A composition of the present invention can be administered by a variety of methods known in the art. The route and/or mode of administration vary depending upon the desired results. The active compounds can be prepared with carriers that protect the compound against rapid release, such as a controlled release formulation, including implants, transdermal patches, and microencapsulated delivery systems. Biodegradable, biocompatible polymers can be used, such as ethylene vinyl acetate, polyanhydrides, polyglycolic acid, collagen, polyorthoesters, and polylactic acid. Many methods for the preparation of such formulations are described by e.g., Sustained and Controlled Release Drug Delivery Systems, J. R. Robinson, ed., Marcel Dekker, Inc., New York, (1978). Pharmaceutical compositions are preferably manufactured under GMP conditions.

The pharmaceutical compositions may be prepared, packaged, or sold in the form of a sterile injectable aqueous or oily suspension or solution. This suspension or solution may be formulated according to the known art, and may comprise, in addition to the active ingredient, additional ingredients such as the dispersing agents, wetting agents, or suspending agents described herein. Such sterile injectable formulations may be prepared using a non-toxic parenterally-acceptable diluent or solvent, such as water or 1 ,3-butane diol, for example. Other acceptable diluents and solvents include, but are not limited to, Ringer's solution, isotonic sodium chloride solution, and fixed oils such as synthetic mono- or di-glycerides. Other parentally-administrable formulations which are useful include those which comprise the active ingredient in microcrystalline form, in a liposomal preparation, or as a component of a biodegradable polymer systems. Compositions for sustained release or implantation may comprise pharmaceutically acceptable polymeric or hydrophobic materials such as an emulsion, an ion exchange resin, a sparingly soluble polymer, or a sparingly soluble salt. While the precise dosage administered of each active ingredient will vary depending upon any number of factors, including but not limited to, the type of animal and type of disease state being treated, the age of the animal and the route(s) of administration. The amounts of various CaR antagonist compounds of formula I to be administered can be determined by standard procedures taking into account factors such as the compound IC₅₀ , ECs₀ , the biological half-life of the compound, the age, size and weight of the patient, and the type of condition or symptom associated with the patient. The importance of these and other factors to be considered are known to those of ordinary skill in the art.

PTH secretion can be measured using techniques known in the art (see, e.g., U.S. 6,031,003, hereby incorporated by reference). For example, PTH secretion can be measured by first suspending cells in parathyroid cell buffer containing 0.5 mM CaCI₂ and 0.1 % bovine serum albumin. Incubations can be performed in plastic tubes (Falcon 2058) containing 0.3 ml_ of the cell suspension with or without small volumes of CaCI₂ and/or organic polycations. After incubation at 37 °C, typically 30 minutes, the tubes can then be placed on ice and the cells pelleted at 2 °C. Samples of the supernatant should then be brought to pH 4.5 with acetic acid and, if needed, stored at - 70 °C. The amount of PTH in bovine cell supernatants can be determined by a homologous radioimmunoassay using GW-1 antibody or its equivalent at a final dilution of 1/45,000. 1251-PTH (65-84; INCSTAR, Stillwater, Minn.) can be used as tracer and fractions separated by dextran-activated charcoal. Counting of samples and data reduction can be performed on a Packard Cobra 5005 gamma counter. For testing PTH levels in human cell supernatants, a commercially available radioimmunoassay kit (INS-PTH; Nichols Institute, Los Angeles, Calif.) which recognizes intact and N-terminal human PTH is preferable because GW-1 antibody recognizes human PTH poorly. In addition, specific assays useful for evaluating the compounds of Formula I include the FLIPR Assay for Evaluating the Potency and Selectivity of Test Compounds; Assay for Evaluating the Effects of Test Compounds on Endogenous PTH Secretion; Evaluation of Effects of Test Compounds on PTH Secretion In Vivo; Effect of Calcium Receptor Antagonist Compound of Formula I on Body Weight, Body Composition and Bone Density in the Aged Intact and Ovariectomized Female Rat; and Fracture Healing Assays as described below.

FLIPR Assay for Evaluating the Potency and Selectivity of Test Compounds Human kidney cell (HEK 293) expressing the calcium receptor (CasR) are used to detect antagonists of the receptor using Fluorometric imaging plate reader (FLIPR, Molecular Devices, Sunnyvale CA). Receptor activation by extracellular calcium results in the release of calcium from intracellular stores into the cytosol. A fluorescent indicator (Fluo-4) is internalized by the cells from growth media and interacts with calcium released into the cytosol to provide a means of quantifying intracellular Ca²⁺ levels and receptor agonism/antagonism. Fluorescence intensity is detected by the FLIPR CCD camera and traced as a function of time. Potential antagonists are identified by their ability to decrease this fluorescent response.

To determine the IC₅₀ values cells are loaded with Fluo4 (2.05 mM Fluo-4, 0.04% pluronic acid, 2.6mM probenecid in 90% DMEM high glucose, 10% dialyzed Fetal Bovine Serum , 1X Pen Strep, 1X L-Glutamine, 3ug/ml Puromycin, 27.5nM Methotrexate ) for 1 hour at 37⁰C. Prior to the addition of test compound cells are washed with a 10 mM HEPES buffer solution. The test compound, for example the compound of Example 1 , is added at various doses (from 1 DM to 3 nM) and pre- incubated with cells for 30 minutes followed by stimulation of the CasR by the addition of 1.7 mM Ca²⁺. IC_5O values are based on the ability of the cells to inhibit the Ca²⁺ induced increase in intracellular Ca²⁺. Fluorescence signal is read 42 seconds after the stimulation of the CasR by the addition of 1.7 mM Ca²⁺.

Assay for Evaluating the Effects of Test Compounds on Endogenous PTH Secretion

Adult male or female Sprague-Dawley rats (Charles River Laboratories, Wilmington, MA) with jugular vein catheter are used in this assay. The test compounds at various doses are given to the animals by various routes of administration including subcutaneous injection, or intraveneous injection. Serum or plasma PTH concentrations are examined before and after dosing at various times using a commercially available rat intact PTH ELISA kit (Immutopics, Inc. San Clemente, CA. Cat.#60-2500).

Evaluation of Effects of Test Compounds on PTH Secretion In Vivo

Overnight fasted male Sprague-Dawley rats (250 g) with jugular vein catheter are used in this study. Whole blood sample is collected from each animal prior to compound treatment for measuring baseline PTH concentrations. The test animals are then given a single dose of the tested compound at 1 mg/kg in glycerol formal: 2% DMSO by intravenous administration via jugular vein. Whole blood samples are collected at 2, 5, 15, 30, 60, 120 and 240 minutes after dosing. Plasma samples are obtained by centrifugation and PTH concentrations are determined using a commercially available rat intact PTH ELISA kit (Immutopics, Inc. San Clemente, CA. Cat.#60-2500). A significant burst of PTH was seen following the treatment with the tested compound (Compound of Example 42). The elevated PTH secretion induced by the tested compound was peak at 2 minutes and returned to baseline level at 30 minutes after dosing (see Figure 1 ).

Effect of Calcium Receptor Antagonist Compound of Formula I on Body Weight. Body Composition and Bone Density in the Aged Intact and Ovariectomized Female Rat

The purpose of this study is to test the effects of test compositions comprising compounds of Formula I in aged intact or ovariectomized (OVX) female rat model. In the following protocol the compound of Formula I can be administered as a pharmaceutically acceptable salt or prodrug thereof. Study Protocol

Sprague-Dawley female rats are sham-operated or OVX at 18 months of age, while a group of rats is necropsied at day 0 to serve as baseline controls. One day post- surgery, the rats are treated with either vehicle or test compound of Formula I, or a combination of test compound of Formula I and other active agent test compound for 59 days. The vehicle or test compound of Formula I is administered either orally, by oral gavage, or by subcutaneous injection (s.c), with the test compound being administered at a therapeutically effective dose. All rats are given s.c. injection of 10 mg/kg of calcein (Sigma, St.Louis, MO) for fluorescent bone label 2 and 12 days before necropsy. On the day of necropsy, all rats under ketamine/xylazine anesthesia are weighed and undergoe dual-energy X-ray absorptiometry (DXA, QDR-45007W, Hologic Inc., Waltham, MA) equipped with Rat Whole Body Scan software for lean and fat body mass determination. The rats are necropsied, then autopsied and blood is obtained by cardiac puncture. The distal femoral metaphysis and femoral shafts from each rat are analyzed by peripheral quantitative computerized tomography (pQCT), and volumetric total, trabecular and cortical bone mineral content and density are determined. Peripheral Quantitative Computerized Tomography (pQCT) Analysis: Excised femurs are scanned by a pQCT X-ray machine (Stratec XCT Research M, Norland Medical Systems, Fort Atkinson, Wl.) with software version 5.40. A 1 millimeter (mm) thick cross section of the femur metaphysis is taken at 5.0 mm (proximal femoral metaphysis, a primary cancellous bone site) and 13 mm (femoral shafts, a cortical bone site) proximal from the distal end with a voxel size of 0.10 mm. Cortical bone is defined and analyzed using contour mode 2 and cortical mode 4. An outer threshold setting of 340 mg/cm³ is used to distinguish the cortical shell from soft tissue and an inner threshold of 529 mg/cm³ to distinguish cortical bone along the endocortical surface. Trabecular bone is determined using peel mode 4 with a threshold of 655 mg/cm³ to distinguish (sub)cortical from cancellous bone. An additional concentric peel of 1% of the defined cancellous bone is used to ensure that (sub)cortical bone was eliminated from the analysis. Volumetric content, density, and area are determined for both trabecular and cortical bone (Jamsa T. et al., Bone 23:155-161 , 1998; Ke, H.Z. et al., Journal of Bone and Mineral Research, 16:765-773, 2001). The experimental groups for the protocol are as follows:

Group I: Baseline controls

Group II: Sham + Vehicle

Group III: OVX + Vehicle

Group IV: OVX + Test Compound of Formula I (in Vehicle) Group V: OVX + Test Compound of Formula I and Additional Active Agent

Note: Group V only employed when it is desired to test a combination of a compound of Formula I and an additional active agent. Fracture Healing Assays Assay For Effects On Fracture Healing After Systemic Administration

Fracture Technigue: Sprague-Dawley rats at 3 months of age are anesthetized with Ketamine. A 1 cm incision is made on the anteromedial aspect of the proximal part of the right tibia or femur. The following describes the tibial surgical technique. The incision is carried through to the bone, and a 1 mm hole is drilled 4 mm proximal to the distal aspect of the tibial tuberosity 2 mm medial to the anterior ridge. Intramedullary nailing is performed with a 0.8 mm stainless steel tube (maximum load 36.3 N, maximum stiffness 61.8 N/mm, tested under the same conditions as the bones). No reaming of the medullary canal is performed. A standardized closed fracture is produced 2 mm above the tibiofibular junction by three-point bending using specially designed adjustable forceps with blunt jaws. To minimize soft tissue damage, care is taken not to displace the fracture. The skin is closed with monofilament nylon sutures. The operation is performed under sterile conditions. Radiographs of all fractures are taken immediately after nailing, and rats with fractures outside the specified diaphyseal area or with displaced nails are excluded. The remaining animals are divided randomly into the following groups with 10 - 12 animals per each subgroup per time point for testing the fracture healing. The first group receives daily gavage of vehicle (water : 100% Ethanol = 95 : 5) at 1 mL/rat, while the others receive daily gavage from 0.01 to 100 mg/kg/day of the compound of Formula I to be tested (1 mL/rat) for 10, 20, 40 and 80 days.

At 10, 20, 40 and 80 days, 10 - 12 rats from each group are anesthetized with Ketamine and sacrificed by exsanguination. Both tibiofibular bones are removed by dissection and all soft tissue is stripped. Bones from 5 - 6 rats for each group are stored in 70% ethanol for histological analysis, and bones from another 5 - 6 rats for each group are stored in a buffered Ringer's solution (+4°C, pH 7.4) for radiographs and biomechanical testing which is performed.

Histological Analysis: The methods for histologic analysis of fractured bone have been previously published by Mosekilde and Bak (The Effects of Growth Hormone on Fracture Healing in Rats: A Histological Description. Bone, 14:19-27, 1993). Briefly, the fracture site is sawed 8 mm to each side of the fracture line, embedded undecalcified in methymethacrylate, and cut frontals sections on a Reichert-Jung Polycut microtome in 8 μm thick. Masson-Trichrome stained mid-frontal sections (including both tibia and fibula) are used for visualization of the cellullar and tissue response to fracture healing with and without treatment. Sirius red stained sections are used to demonstrate the characteristics of the callus structure and to differentiate between woven bone and lamellar bone at the fracture site. The following measurements are performed: (1 ) fracture gap - measured as the shortest distance between the cortical bone ends in the fracture, (2) callus length and callus diameter, (3) total bone volume area of callus, (4) bony tissue per tissue area inside the callus area, (5) fibrous tissue in the callus, and (6) cartilage area in the callus. Biomechanical Analysis: The methods for biomechanical analysis have been previously published by Bak and Andreassen (The Effects of Aging on Fracture Healing in Rats. Calcif Tissue lnt 45:292-297, 1989). Briefly, radiographs of all fractures are taken prior to the biomechanical test. The mechanical properties of the healing fractures are analyzed by a destructive three- or four-point bending procedure. Maximum load, stiffness, energy at maximum load, deflection at maximum load, and maximum stress are determined.

A calcium receptor antagonist may be usefully combined with another pharmacologically active compound, or with two or more other pharmacologically active compounds, particularly in the treatment of osteoporosis. For example, a calcium receptor antagonist, particularly a compound of the formula I, or a pharmaceutically acceptable salt or solvate thereof, as defined above, may be administered simultaneously, sequentially or separately in combination with one or more agents selected from: selective estrogen receptor modulators (SERMs), bisphosphonates, parathyroid hormone (PTH) and fragments and analogues thereof, estrogens, calcitonins, synthetic steroids, synthetic isoflavones, vitamin D analogues, vitamin K analogues, strontium salts, cathepsin K inhibitors, α_vβ₃ integrin (vitronectin) antagonists, prostaglandin (PGE2) receptor agonists and receptor activator of nuclear factor KB ligand (RANKL) inhibitors as described hereinabove. The following non-limiting Preparations and Examples illustrate the preparation of compounds of the present invention. ¹H Nuclear magnetic resonance (NMR) spectra were in all cases consistent with the proposed structures. Characteristic chemical shifts (δ) are given in parts-per-million downfield from tetramethylsilane using conventional abbreviations for designation of major peaks: e.g. s, singlet; d, doublet; t, triplet; q, quartet; m, multiplet; br, broad. The mass spectra (m/z) were recorded using either electrospray ionisation (ESI) or atmospheric pressure chemical ionisation (APCI). The following abbreviations have been used for common solvents and various reagents: BCb, boron trichloride; BEP, 2- bromo-1 -ethyl pyridinium tetrafluoroborate; BOP, (Benzotriazole-1-yl-oxy-tris- (dimethylamino)-phosphonium hexafluorophosphate);CDCI₃, deuterochloroform; CDI, N.N'-Carbonyldiimidazole; CD₃OD, deuteromethanol; CH₂CI₂ or DCM, dichloromethane; CHCI₃, chloroform; DCC, N.N'-Dicyclohexylcarbodiimide; DCE, dichloroethane; DIEA, diisopropylethylamine; DMF, dimethylformamide; DMSO, dimethylsulfoxide; DMSO-d₆, deuterodimethylsulfoxide; EDC, 1 -ethyl-a-^-dimethyllaminopropyOcarbodiimide hydrochloride; Et₃N or TEA, triethylamine; EtOAc, ethyl acetate; EtOH, ethanol; g, gram; HBTU, O-(Benzotriazol-1-yl)-Λ/,Λ/,Λ/',Λ/'-tetramethyluronium hexafluorophosphate; HCI, hydrochloric acid; HOAc, acetic acid; HOBT, N-hydroxybenzotriazole; H₂SO₄, sulfuric acid; K₂CO₃, potassium carbonate; kg, kilogram; M, molar; MeOH, methanol; mg, milligram; MgSO₄, magnesium sulfate; ml_, milliliter; OL, microliter; mmol, millimole; Dmol, micromole; NaCI, sodium chloride; NaHCO₃, sodium bicarbonate; N₂, nitrogen; NaOH, sodium hydroxide; Na₂SO₄, sodium sulfate; NH₄OH, ammonium hydroxide; NMP, N-methylpyrrolidone; RT, room temperature; THF, tetrahydrofuran; and p-TSOH, para-toluene sulfonic acid. Where thin layer chromatography (TLC) has been used it refers to silica gel TLC using silica gel 60 F₂₅₄ plates, R_f is the distance traveled by a compound divided by the distance traveled by the solvent front on a TLC plate. Preparative TLC refers to purification of compounds on a preparative TLC plate. HPLC refers to high performance liquid chromatography.

The following general procedures and specific examples are included for illustrative purposes and are not to be construed as a limitation to this disclosure.

General Synthesis Procedure 1 Cvclization Step: The appropriate starting material of general Formula V (see Reaction Scheme 1 and 1A above) is weighed out (0.3 mmol) in a reaction vial and to the vial is added a 0.018M solution of p-toluenesulfonic acid in glacial acetic acid such that 0.05 equivalents of p-toluenesulfonic acid is delivered, (~840ul). An appropriate aldehyde of general formula R²CHO, such as anisaldehyde, is added neat, ~40ul (1.05 equiv.), to each reaction vial. The vial is capped and placed on a heated shaker plate, at 95 ⁰C for 9 hours. Following the heating period, the reaction is allowed to continue to agitate at RT until assay and work up. The reaction mixture is combined with 2 ml_ of EtOAc, the reaction mixture is then washed twice with 2.5 mL portions of 2N NaOH, final pH of the wash is approx 12, (this amount is actually less then the stoichiometric amount of base needed to neutralize the acetic acid, however when the stoichiometric amount was used on a trial work up, the pH after of the aqueous layer was >12, as a precaution the amount of base was lowered until a pH of the aqueous layer was ~12 (the NaOH solution used was not a volumetrically prepared solution). Following each wash the aqueous layer is decanted using a syringe. The neutralized reaction mixture is then washed once with 1/2 saturated NaCI, approx 1 mL of water and 1 mL of brine. The organic layer is decanted and passed through an extract filter cartridge. The filtrate is evaporated to dryness to provide the crude reaction product which is carried on to the alkylation step.

Alkylation Step: The alkylation reaction is run at approximately 0.1 M concentration total volume in DMF/aqueous potassium carbonate such that 10% of the volume is the aqueous potassium carbonate solution. Thus, the crude substrate from the cyclization step is combined with the appropriate amount of DMF, vortexed, followed by addition of the appropriate amount of the potassium carbonate solution. The reaction mixture is placed on a heated 80 ⁰C shaker plate and allowed to warm over approximately 15 minutes. The appropriate amount of the alkylating agent of general formula R¹LG, such as 3-fluorophenyl ethyl bromide, is then added to the warm reaction mixture while gentle mixing is continued. The agitation rate is then increased and the reaction is heated at 80 ⁰C for 31 hours, followed by continued stirring at RT until work up. The crude reaction solution is concentrated in vacuo to remove DMF. To the vial is added 2 mL of EtOAc and 2 mL of water, then the aqueous layer is decanted. 2 mL of brine is then added, the organic layer is separated, passed through an extraction filter, and the filtrate is concentrated in vacuo to dryness. Toluene (2 mL) is then added to the vial, vortexed and then removed by concentration in vacuo to provide the crude alkylated product. In cases where further deprotection or derivatization is not required to provide a compound of Formula I the residue is purified by chromatography on silica gel; normal phase HPLC or reverse phase HPLC methods to provide the compound of Formula I.

Deprotection of Methoxy to Hydroxy Step: It is to be understood that this step is employed to convert compounds in which R² contains a methoxy group that is to be converted to a hydroxy group in R² of a compound of Formula I. The crude reaction product obtained from the previous step is dissolved in 50OuI-IOOOuI of dry DCM, and the reaction vessel is capped and purged with nitrogen. Approximately 2.4 mL to 3 mL of BCI3, is added to the reaction mixture via a gas tight syringe. The reaction is placed on a shaker plate and allowed to agitate at RT. The reaction is quenched by adding 1.5 mL of water, quickly recapping, shaking and carefully venting by loosening the cap. Pressure build-up subsides within 1 minute. The quenched reaction can form an emulsion, with only minor separation of the organic layer. The reaction is filtered through approx 500 mg of celite. The filtrate is collected into 13x125 test tubes; and the organic layer is then decanted into tared Arqule vials for evaporation. Following evaporation the net weight is obtained. The residue is then purified by silica gel chromatography; normal phase HPLC or reverse phase HPLC to provide the compound of Formula I.

Preparation of Intermediates

Preparation 1 : 1.1.1-Trifluoro-3-mercapto-propan-2-one

1 M NaOH (10 mL) was added slowly to a solution of sodium hydrogensulfide (2.056 g, 36.7 mmol) in water (8 mL) at 0 ⁰C. A solution of i-bromo-3,3,3- trifluoroacetone (5.0 g, 26.2 mmol) in diethyl ether (2.5 mL) was added dropwise and the resulting mixture was stirred at 0 ⁰C under nitrogen for 1 hour. The reaction mixture was used for the next step as is.

Preparation 2: 2-Amino-4-hvdroxy-4-trifluoromethyl-4.5-dihvdro-thiophene-3- carboxylic acid methyl ester

Methyl cyanoacetate (2.725 g, 27.5 mmol) was added to the reaction mixture from Preparation 1 at 0 ⁰C. Triethylamine (3.8 mL, 27.5 mmol) was added slowly and the resulting yellow mixture was stirred at 0 ⁰C for 1 hour. The reaction mixture was warmed to room temperature and stirred at room temperature for 1.5 hours, then filtered and the solid that was collected by filtration was washed with water and dried in vacuo to give 2.584 g of off-white solid. ¹H NMR (CDCI₃) δ 5.18 (1H, bs), 3.81 (s, 3H), 3.49 (dd, 2H), 1.71 (bs, 2H). MS m/z 244.2 (M+H)⁺.

Preparation 3: 2-Amino-4-trifluoromethyl-thiophene-3-carboxylic acid methyl ester

The solid starting material, 2-Amino-4-hydroxy-4-methyl-4,5-dihydro-thiophene-3- carboxylic acid methyl ester from Preparation 2, was heated until melted (about 175 ⁰C) and stirred at this temperature for 10 minutes. On cooling, the reaction mixture gave 2.236 g of brown solid product. ¹H NMR (CDCI₃) δ 6.75 (s, 1 H), 3.85 (s, 3H). MS m/z 226.2 (M+H)⁺. Preparation 4: 2-(2-Methoxy-benzoylamino)-4-trifluoromethyl-thiophene-3- carboxylic acid methyl ester

A mixture of the thiophene starting material (Preparation 3, 0.20 g, 8.9 mmol), 2- methoxybenzoyl chloride (0.152 g, 8.9 mmol) and triphenylphosphite (0.28 mL, 10.7 mmol, 1.2 equiv.) in anhydrous pyridine (2 mL) was heated in a microwave at 150 ⁰C for

10 minutes. The crude material was used immediately in next step. MS m/z 358.2 (M-

H)-.

Preparation 5: 2-Amino-4-hvdroxy-4-trifluoromethyl-4.5-dihydro-thiophene-3- carboxylic acid ethyl ester

Triethylamine (0.65 mL, 46.5 mmol) was added dropwise to a mixture of ethyl cyanoacetate (0.526 g, 46.5 mmol) and 1 ,1 ,1-trifluoro-3-mercapto-propan-2-one (0.638 g, 44.3 mmol) in anhydrous DMF (3 mL) at room temperature under nitrogen. After the addition was complete the reaction mixture was heated at 45 ⁰C for 45 minutes. The reaction mixture was diluted with water (30 mL) and extracted with ethyl acetate (4x25 mL). The combined extracts were washed with water (2x30 mL), dried over MgSO₄ and concentrated in vacuo to give 1.033 g of brown oil. This material was purified by flash chromatography eluting with ethyl acetate/hexane. The product was then triturated with heptane, the solid collected by filtration and dried in vacuo to give 0.188 g of orange solid. ¹H NMR (CDCI₃) δ 4.23-4.35 (m, 2H), 3.41-3.56 (m, 1H), 1.33 (t, 3H). MS m/z 258.2 (M+H)⁺.

Preparation 6: 2-Amino-4-trifluoromethyl-thiophene-3-carboxylic acid ethyl ester

A total of 4.193 g of the hydrated starting material (compound of Preparation 5) was placed in a flask with condenser on top and nitrogen inlet. The flask was heated to 145 ⁰C for 10 minutes and monitored by TLC. The solid starting material liquefies at approximately 130 ⁰C. The flask was then cooled to RT and water removed under vacuum. The product was obtained as a tan solid, 3.45 g (88%). ¹H NMR (CDCI₃) δ 6.75 (s, 1H), 4.298 (q, 2H), 1.34 (t, 3H). MS m/z 240.2 (M+H)⁺. Preparation 7: 2-(2-Methoxy-benzoylarnino)-4-trifluoromethyl-thiophene-3- carboxylic acid ethyl ester

A mixture of amino thiophene starting material (Preparation 6, 0.125 g, 0.52 mmol), 2-methoxybenzoyl chloride (0.089 g, 0.52 mmol) and triphenylphosphite (0.16 mL, 0.62 mmol) in anhydrous pyridine (2.0 mL) was heated in a microwave at 150 ⁰C for 10 minutes. The mass spectrum indicated that the reaction mixture contains mostly the amide intermediate and a small amount of the desired product. This mixture was used immediately in the next step. MS m/z 374.3 (M+H)⁺. Preparation 8: 2-Amino-thiophene-3-carboxylic acid ethyl ester

J_^r^~

NH₂

Triethylamine (1.81 ml_, 13.3 mmol) was added dropwise over 10 minutes to a mixture of ethyl cyanoacetate (3.0 g, 26.6 mmol) and 1 ,4-dithiane-2,5-diol (2.025 g, 13.3 mmol) in anhydrous DMF (10 ml_) at RT under nitrogen. After the addition was complete the reaction mixture was heated at 45 ⁰C for 30 minutes. The reaction mixture was then diluted with 0.4M acetic acid (70 ml_) and extracted with ethyl acetate (4x50 ml_). The combined extracts were washed with water (2x25 ml_), dried over MgSC^ and concentrated in vacuo to give 5.44 g of brown oil. The product was purified by flash chromatography eluting with hexane/ethyl acetate to yield 2.822 g of the title compound.

¹H NMR (CDCI₃) δ 6.98 (d, 1 H), 6.18 (d, 1H), 4.27 (q, 2H), 1.34 (t, 3H); MS m/z 172.1

(M+H)⁺.

Preparation 9: 5-Amino-3-(trifluoromethyl)isothiazole-4-carbonitrile

Trifluoroacetonitrile (25.00 g, 0.26 mol) was bubbled into a suspension of 2- cyanothioacetamide (5.00 g, 0.049 mol) and triethylamine (8.4 mL) in ethanol (250 mL) at -78 ⁰C under nitrogen and was stirred at this temperature for 3 hours. At this time, the reaction was warmed to room temperature and used immediately in the next reaction. At this time, 11.2 mL of a 30% solution of hydrogen peroxide was added to the reaction mixture and heated to 60 ⁰C under nitrogen atmosphere for 1 hour. The reaction was cooled to room temperature and a solution of sodium bisulfite in water was added. The resulting mixture was filtered to remove undissolved solids and the filtrate was concentrated in vacuo to provide an orange solid which was purified by silica gel chromatography to provide 4.59 grams (48% yield of desired 5-amino-3- (trifluoromethyl)isothiazole-4-carbonitrile. 1H NMR (DMSOd₆) δ 8.56 (s, 2H). MS m/z 193.2 (M+H)⁺. Preparation 10: 5-amino-3-(trifluoromethyl) isothiazole-4-carboxamide

To a round flask containing 5-amino-3-(trifluoromethyl)isothiazole-4-carbonitrile (Preparation 9, 670 mg, 3.37 mmol) in anhydrous ethanol (30 ml_) was added 8.0 mL of NaOH (1.0 M) and 8 mL of hydrogen peroxide (30% solution). The reaction mixture was refluxed for 3 hours and was then evaporated to provide a red residue which was purified by silica gel chromatography (eluted with heptane/EtOAc) to afford 0.282 grams (38% yield) of 5-amino-3-(trifluoromethyl) isothiazole-4-carboxamide. 1H NMR (DMSO-d₆) δ 7.20 (s, 2H), 7.4 (2H). MS m/z 210.1 (M-H)^".

Preparation 11 : 6-(2-methoxyphenvD-3-(trifluoromethyl)isothiazolor5.4- dlpyramid-4(5H)-one

A solution of 5-amino-3-(trifluoromethyl) isothiazole-4-carboxamide (Preparation 10, 150mg, 0.71 mmol), 2-methoxybenzaldehyde (109 mg, 0.80 mmol) and p-TSOH (8mg, 0.042 mmol) in 3.5 mL of glacial acetic acid was heated at 95 ⁰C under an atmosphere of nitrogen for 9.5 hrs. The reaction mixture was then concentrated in vacuo to give a brown oil which was further purified by silica gel chromatography to provide 126 mg (54% yield) of the desired 6-(2-methoxyphenyl)-3- (trifluoromethyl)isothiazolo [5,4-d]pyramid-4(5H)-one.

¹H NMR (DMSO-de) δ 12.9 (s, 1 H)₁ 7.89 (d, 1H), 7.59 (m, 1 H), 7.21 (d, 1H), 7.05 (m, 1H), 3.99 (s, 3H). MS m/z 326.2 (M+H)⁺.

Preparation 12: 6-(2-methoxyphenyl)-5-phenethyl-3-(trifluoromethvhisothiazolo f5.4-dl pyramid-4-one

A mixture of 6-(2-methoxyphenyl)-3-(trifluoromethyl)isothiazolo[5,4-d]pyramid- 4(5H)-one (Preparation 11 , 100 mg, 0.31 mmol), (2-bromoethyl)benzene (74.0 mg, 0.40 mmol) and potassium carbonate (55 mg, 0.40 mmol) in anhydrous DMF (4 mL) was heated at 80⁰C under an atmosphere of nitrogen for 1.5 hours. The reaction mixture was diluted with H₂O (10 mL) and the resulting mixture was extracted with EtOAc (4 x10 mL). The combined extracts were washed with H₂O (2x 5 mL), dried over MgSO₄ and concentrated to provide a yellow oil that was purified by silica gel chromatography to afford 65 mg (47% yield) of the desired 6-(2-methoxyphenyl)-5-phenethyl-3- (trifluoromethyl)isothiazolo [5,4-d]pyramid-4-one. 1H NMR (DMSO-d₆) δ 7.60 (t, 1H), 7.39 (d, 1H), 7.21 (d, 1H), 7.05 (m, 4H), 6.76 (m, 2H) 4.20 (m, 1 H), 3.89 (s, 3H), 3.62 (m, 1 H), 2.70 (m, 2H). MS m/z 432.3 (M+H)⁺.

Preparation 13: methyl 5-amino-3-trifluoromethyl)isothiazole-4-carboxylate

Methanol (50 ml_) was added slowly to a solution of 5-amino-3-(trifluoromethyl) isothiazole-4-carboxamide (Preparation 10, 547 mg, 2.59 mmol) in concentrated sulfuric acid (4.0 ml_). The resulting solution was refluxed for 65 hrs. The reaction mixture was cooled to room temperature and concentrated in vacuo to remove the methanol. The remaining aqueous solution was quenched by the careful addition of saturated NaHCO₃ solution. The resulting suspension was extracted with EtOAc (4x 25 ml_). The combined organic layers were collected, dried over magnesium sulfate, and concentrated in vacuo to provide an off-white solid that was purified by silica gel chromatography to afford 400 mg (68% yield) of desired methyl 5-amino-3- trifluoromethyl)isothiazole-4-carboxylate. ¹H NMR (DMSO-d₆) δ 8.19 (s, 2H)₁ 3.96 (s, 3H). MS m/z 225.1 (M+H)⁺. Preparation 14: methyl 5-(2-methoxybenzamido)-3-(trifluoromethyl)isothiazole-4- carboxylate

A mixture of methyl 5-amino-3-trifluoromethyl)isothiazole-4-carboxylate (Preparation 13, 154 mg, 0.69 mmol), 2-methoxybenzoyl chloride (74.0 mg, 0.40 mmol) and triphenylphosphite (0.22 mL, 0.84 mmol) was microwaved at 150 ⁰C for twelve minutes and this mixture was used immediately in the next reaction step.

Preparation 15: methyl 5-amino-3-trifluoromethyl)isoxazole-4-carboxylate

1535-1538.

Preparation 16: 2-methyl-3-nitropvridine

A mixture of 2-chloro-3-nitropyridine (1.6g, 10.09mmol), Pallac tetrakis(triphenylphosphine) (1170mg, 1.01 mmol), methylboronic acid (665mg, mmol ) and potassium carbonate (4180mg, 30.3 mmol) was refluxed in dioxane 1 days. The reaction was cooled to room temperature, and then filtered. The filtrate concentrated and the residue was purified by flash column chromatography (ι EtOAc/Hexanes) to afford 760mg (55%) of 2-methyl-3-nitropyridine. ¹H NMR (CDC 8.71 (tetra, 1.7Hz, 5.0Hz, 1H), 8.26 (tetra, 1.7Hz, 8.3Hz, 1H)₁ 7.34 (dd, 5.( 8.3Hz, 1 H), 2.85 (s, 3H). MS m/z 139.1(M+H)⁺.

Preparation 17: Methoxy-(3-nitropyridin-2-yl)-methanol

A mixture of 2-methyl-3-nitropyr "idine (760rmg, 5.5mmol) and selenium oxide (733mg, 6.6mmol) was refluxed in dioxane for 2 days. The solvent was removed. T residue was re-taken up in MeOH, loaded on silica gel and purified by column chromatography (EtOAc/Heptane=1/1 ) to afford a mixture (960mg, 95%) of methoxyi nitropyridin-2-yl)methanol and 3-nitropicolinaldehyde. MS m/z 185.0 (M+H)⁺. Preparation 18: (/?)-5-amino-N-(1-phenylpropan-2-yl)-3- (trifluoromethyl)isoxazole-4-carboxamide

To a flame dried flask was added L-Amphetamine (1610 mg, 9.378 mmol) and toluene (40 ml). The mixture was cooled to 0 ⁰C in an ice bath. Trimethyl aluminum (4.69 ml of 2M toluene solution) was added dropwise. The resulting mixture was stirred at room temp for 2 hours, then methyl 5-amino-3-(trifluoromethyl)isoxazole-4- carboxylate (985 mg, 4.69 mmol) was added and the mixture was refluxed for 12 hours. The reaction was cooled, then quenched with a saturated solution of potassium sodium tartrate to break aluminum salts, and extracted with ethyl acetate. The organic layer was washed with H₂O, brine, dried over Na₂SO4, concentrated and purified by silica gel chromatography with 20% ethyl acetate/heptane to yield the title compound as a white solid (703 mg, 24%). ¹H NMR (CDCI₃) δ 7.30-7.15(m, 5H), 6.48 (brS, 2H), 5.61 (brS, 1H), 4.34 (m, 1 H), 2.81 (m, 2H), 1.17 (d, 6.6Hz, 3H). MS m/z 314.1 (M+H)⁺.

Preparation 19: (f?)-6-(3-nitropyridin-2-yl)-5-(1 -phenylpropan-2-yl)-3- (trifluoromethyl)isoxazolor5.4-dipyrimidin-4(5H)-one

A mixture of (/?)-5-amino-N-(1-phenylpropan-2-yl)-3-(trifluoromethyl)isoxazole-4- carboxamide (400 mg, 1.28 mmol), methoxy(3-nitropyridin-2-yl)methanol (470 mg, 2.55 mmol) and p-TSOH (11.0 mg ) in xylene (10 ml_) was heated at 150°C (bath) for 3 days. The solvent was removed, and the residue was purified by silica gel chromatography to afford the titled compound (250 mg, 44%). ¹H NMR (CDCI₃) δ 8.99 (tetra, 1.3Hz, 4.6Hz, 1 H), 8.62 (tetra, 1.3 Hz, 8.3Hz, 1 H), 7.79 (dd, 4.6Hz, 8.3Hz, 1H), 7.18 (m, 3H), 6.92(m, 2H), 4.00 (m, 1 H), 3.61 (m, 1H), 3.33 (dd, 4.6Hz, 13.3Hz, 1 H)₁ 1.57 (d, 6.2, 3H). MS m/z 446.1 (M+H)⁺.

Preparation 20: (ffl-6-(3-aminopyridin-2-vO-5-(1-phenylpropan-2-yl)-3- (trifluoromethv0isoxazolof5.4-dipyrimidin-4(5H)-one

A mixture of (f?)-6-(3-nitropyridin-2-yl)-5-(1-phenylpropan-2-yl)-3- (trifluoromethyl)isoxazolo[5,4-d]pyrimidin-4(5H)-one (246mg, 0.552mmol) and Tin (II) chloride dihydrate (623 mg, 2.76 mmol) was refluxed for 4 days. The reaction was diluted with EtOAc, washed with H₂O, brine. The organic layer was dried over MgSO₄. The solvent was removed and the residue was passed through a short silica gel column to afford the title compound (150mg, 65%). ¹H NMR (CDCI₃) δ 8.10 (dd, 1.3Hz, 4.2Hz, 1H), 7.23 (m, 1H), 7.11 (m, 4H), 6.91 (m, 2H), 4.63 (m, 1H), 4.22 (brS, 2H), 3.60(dd, 8.7Hz, 13.3Hz, 1 H), 3.11 (dd, 7.1 Hz, 13.7Hz, 1H), 1.77 (d, 6.6Hz, 3H). MS m/z 416.1 (M+H)⁺. Preparation 21 : 5-(2-fluorophenethyl)-6-(3-aminopyridin-2-yl)-3-(trifluoromethyl) isoxazolof5.4-dipyrimidin-4(5H)-one

The title compound was prepared in the same manner as Preparation 19 using N-(2-fluorophenethyl)-5-amino-3-(trifluoromethyl)isoxazole-4-carboxamide and methoxy(3-nitropyridin-2-yl)methanol to provide 5-(2-fluorophenethyl)-6-(2-nitrophenyl)- 3-(trifluoromethyl)isoxazolo[5,4-d]pyrimidin-4(5H)-one which is reduced in a manner analogous to Preparation 20. ¹H NMR (CDCI₃) 58.15 (m, 1H), 7.27 (m, 1H), 7.15 (m, 3H), 7.00 (m, 1 H), 6.91 (m, 1H), 4.48 (t, 7.9Hz, 2H), 3.18 (t, 7.9Hz, 2H). MS m/z 420.1 (M+H)⁺. Preparation 22: 5-Amino-3-(trichloromethyl)isothiazole-4-carbonitrile

Et₃N (11.6 ml, 83.2 mmol) was added slowly to a suspension of trichloroacetonitrile (10.000 g, 69.3 mmol) and 2-cyanothioacetamide (6.940 g, 69.3 mmol) in EtOH (150 ml_) at RT under N₂. The resulting solution was stirred at RT for 45 minutes, heated at 60 ⁰C for 45 minutes, then concentrated in vacuo to a brown solid. This material was purified by flash chromatography eluting with heptane/ethyl acetate to yield 6.714 g (40%) of the title compound. ¹H NMR (DMSO-d₆) D 8.42 (s, 2H). MS m/z 240.0 (M-H-If₁ 242.0 (M-H+I ) , 244.0 (M-H+3)^". Preparation 23: 5-Amino-3-(trichloromethyl)isothiazole-4-carboxamide

A solution of 5-Amino-3-(trichloromethyl)isothiazole-4-carbonitrile (0.200 g, 0.82 mmol) in concentrated H₂SO₄ (2.0 mL, 37.5 mmol) was heated at 70 ⁰C for 5 hours. The reaction mixture was neutralized by its careful addition to saturated NaHCO₃ solution (30 mL). The resulting mixture was extracted with ethyl acetate (3 x 20 mL). The combined extracts were dried over MgSO₄ and concentrated in vacuo to give 0.158 g of brown residue. This material was purified by flash chromatography eluting with heptane/ethyl acetate to yield 0.138 g (64%) of the title compound. ¹H NMR (DMSO-d₆) D 7.50 (brs, 2H), 6.99 (brs, 2H). MS m/z 258.0 (M-H-1 )^", 260.1 (M-H+1)^', 262.0 (M- H+3)^".

Preparation 24: 6-(2-Metho^χyphenyl)-3-(trichloromethyl)isothiazolor5.4-d1pyrimidin- 4(5H)-one

A mixture of 5-Amino-3-(trichloromethyl)isothiazole-4-carboxamide (0.240 g, 0.92 mmol) 2- methoxybenzaldehyde (0.132g, 0.97 mmol) and p-TsOH (0.009 g, 0.046 mmol) in glacial HOAc (3.5 mL) was heated at 95° under N2 for 1 hr, then evaporated in vacuo to give 0.424 g of yellow solid. This material was purified by flash chromatography eluting with heptane/ethyl acetate to yield 0.258 g (74%) of the title compound. ¹H NMR (CDCI₃) D 11.42 (brs, 1H), 8.57 (dd, 1 H), 7.62 (m, 1H), 7.22 (m, 1 H), 7.13 (d, 1 H), 4.11 (s, 3H). MS m/z 374.0 (M-H-I) , 376.0 (M-H+1)^", 378.0 (M-H+3)^'.

Preparation 25: 6-(2-Methoxyphenyl)-5-phenethyl-3- (trichloromethyl)isothiazolor5.4-d1 pyrimidin-4(5H)-one

A solution of 6-(2-Methoxyphenyl)-3-(trichloromethyl)isothiazolo[5,4-d]pyrimidin- 4(5H)-one (0.100 g, 0.27 mmol), (2-bromoethyl)benzene (0.064 g, 0.34 mmol) and K₂CO₃ (0.041 g, 0.3 mmol) in anhydrous DMF (3 mL) was heated at 80° under N₂ for 4 hours. The reaction mixture was diluted with water (10 mL) and extracted with ethyl acetate (3 x 5 mL). The combined extracts were washed with water (2 x 5 mL), dried over MgSO₄ and concentrated in vacuo to give 0.141 g of yellow oil. This material was purified by flash chromatography, eluting with heptane/ethyl acetate to yield 0.050 g (39%) of the title compound. ¹H NMR (CDCI₃) D 7.56 (m, 1H), 7.17 (m, 3H), 7.10 (m, 2H)₁ 7.04 (d, 1H), 6.82 (m, 2H), 4.50 (m, 1H), 3.84 (s, 3H)₁ 3.80 (m, 1H), 2.92 (m, 1H)₁ 2,82 (m, 1H). MS m/z 480.0 (M+H-1)⁺, 482.1 (M+H+1)⁺, 484.2 (M+H+3)⁺.

Preparation 26: Dimethyl 5-aminoisothiazole-3-4-dicarboxylate

A solution of 5-Amino-3-(trichloromethyl)isothiazole-4-carboxamide (0.750 g,

2.88 mmol) and concentrated H₂SO₄ (3.0 mL, 56.3 mmol) in methanol (38 mL, 938 mmol) was refluxed under N₂ for 10 days. The reaction mixture was neutralized by its careful addition to a suspension of NaHCO₃ (15 g) in water (100 mL) with stirring. The resulting mixture was concentrated in vacuo to remove the methanol, then extracted with ethyl acetate (4 x 50 mL). The combined extracts were dried over MgSO₄ and concentrated in vacuo to give 0.478 g of orange residue. This material was purified by flash chromatography eluting with heptane/ethyl acetate to yield 0.287 g (36%) of the title compound. ¹H NMR (DMSO-d₆) D 7.96 (brs, 2H), 3.78 (s, 3H), 3.70 (s, 3H). MS m/z 215.0 (M-H)-. Preparation 27: (R)-2-Methoxy-N-(1-phenylpropan-2-v0benzamide

A solution of o-anisoyl chloride (1.907 g, 11.18 mmol) in anhydrous CH₂CI₂ (10.0 mL) was added slowly to a solution of L-amphetamine hydrochloride (2.016 g, 11.74 mmol) and triethylamine (3.27 mL, 23.5 mmol) in anhydrous CH₂CI₂ (43 mL) at 0° under

N₂. The reaction mixture was warmed to room temperature and stirred overnight, then diluted with ethyl acetate. The resulting mixture was washed once with saturated aqueous sodium bicarbonate, twice with 1 M NaOH, twice with 1 M HCI, twice with saturated aqueous sodium bicarbonate, then dried over Na₂SO₄ and evaporated in vacuo to give 2.99 g (99%) of the title compound. ¹H NMR (CDCI₃) D 8.21 (dd, 1H),

7.77 (brs, 1 H), 7.42 (m, 1 H), 7.30 (m, 2H), 7.26 (m, 3H), 7.07 (m, 1 H)₁ 6.94 (d, 1 H), 4.51

(m, 1 H), 3.85 (s, 3H), 2.97 (dd, 1 H), 2.83 (m, 1H). MS m/z 270.3 (M+H)⁺.

Preparation 28: (R)-Methyl 6-(2-methoxyphenyl)-4-oxo-5-(1-phenylpropan-2-yl)- isothiazolof5.4-diPVrimidine-3-carboxylate

Oxalyl chloride (0.056 mL, 0.64 mmol) was added dropwise with stirring to a solution of (R)-2-Methoxy-N-(1-phenylpropan-2-yl)benzamide (0.149 g, 0.55 mmol) and 2,6-lutidine (0.10 mL, 0.83 mmol) in anhydrous dichloroethane (3.0 mL) at 0 ⁰C under N₂. The resulting mixture was stirred at 0 ⁰C for 30 minutes, a suspension of dimethyl 5-aminoisothiazole-3-4-dicarboxylate (0.100 g, 0.46 mmol) in xylene (8.0 mL) was added, and the reaction mixture was refluxed under N₂ for 67 hours. The reaction mixture was neutralized by its careful addition to saturated NaHCO₃ solution (20 mL) then extracted with ethyl acetate (4 x 20 mL). The combined extracts were washed with water (20 mL), dried over MgSO₄ and concentrated in vacuo to give 0.204 g of brown residue. This material was purified by flash chromatography eluting with heptane/ethyl acetate to yield 0.027 g (14%) of the title compound. ¹H NMR (CDCI₃) D 7.43 (m, 1H), 7.16 (m, 3H) 6.90 (m, 2H), 6.76 (d, 2H), 6.24 (m, 1H), 4.12 (s, 3H), 3.96 (m, 1H), 3.79 (s, 3H), 3.63 (m, 1 H), 2.87 (m, 1 H), 1.76 (d, 3H). MS m/z 436.3 (M+H)⁺. Preparation 29: (R)-6-(2-Methoxyphenyl)-4-oxo-5-π-phenylpropan-2-yl)-isothiazolor5.4- dipyrimidine-3-carboxamide

A mixture of (R)-Methyl 6-(2-methoxyphenyl)-4-oxo-5-(1-phenylpropan-2-yl)- isothiazolo[5,4-d]pyrimidine-3-carboxylate (0.026 g, 0.06 mmol) in concentrated NH₄OH (1.0 ml_, 25.7 mmol) was stirred at room temperature for 24 hours, then evaporated in vacuo to give 0.025 g (100%) of the title compound. ¹H NMR (CDCI₃) D 7.45 (m, 1H), 7.20 (m, 1 H) 7.15 (m, 3H), 6.92 (m, 2H), 6.74 (d, 2H), 6.25 (dd, 2H), 4.34 (m, 1H), 3.81 (s, 3H), 3.61 (dd, 1H), 2.88 (dd, 1H), 1.77 (d, 3H). MS m/z 421.3 (M+H)⁺.

Preparation 30: (R)-6-(2-Methoxyphenyl)-4-oxo-5-(1 -phenylpropan-2-yl)-isothiazolof5.4- d1pyrimidine-3-carbonitrile

Trifluoroacetic anyhydride (0.064 ml_, 0.54 mmol) was added to a solution of (R)- 6-(2-Methoxyphenyl)-4-oxo-5-(1-phenylpropan-2-yl)-isothiazolo[5,4-d]pyrimidine-3- carboxamide (Preparation 29, 0.019 g, 0.05 mmol) and anhydrous pyridine (0.073 ml_, 0.90 mmol) in anhydrous CH₂Cb (4.0 ml_) at 0° under N₂. The resulting solution was stirred at 0° for 30 minutes then diluted with water (5.0 ml_). The organic layer was separated and the aqueous layer was extracted with CH₂CI₂ (2 x 5 ml_). The combined organic layers were dried over MgSO₄ and concentrated in vacuo to give 0.030 g of orange residue. This material was purified by flash chromatography eluting with heptane/ethyl acetate to yield 0.010 g (56%) of the title compound. ¹H NMR (CDCI₃) D 7.45 (m, 1H), 7.17 (m, 3H), 6.92 (m, 2H), 6.77 (d, 2H), 6.21 (dd, 1 H), 4.24 (m, 1H), 3.80 (s, 3H), 3.65 (dd, 1H), 2.89 (dd, 1H), 1.78 (d, 3H). MS m/z 403.2 (M+H)⁺.

Preparation 31 : 2-amino-N-phenethyl-4-(trifluoromethyl)thiophene-3-carboxamide

Phenethylamine (110 mg, 0.87 mmol) in 2 mL of anhydrous toluene was cooled to 5⁰C . To this solution, trimethylaluminum (60 mg, 0.90 mmol) was added dropwise. The mixture was warmed to room temperature and stirred for 2 hours. To this reaction mixture, a solution of toluene (2 mL) and methyl 2-amino-4-(trifluoromethyl)thiophene- 3-carboxylate (100 mg, 0.44 mmol) was added and heated to reflux for one hour. At this time, the reaction was cooled and quenched with potassium sodium tartrate. The mixture was diluted with water and extracted twice with ethyl acetate. The organic layer was collected, dried over magnesium sulfate and concentrated to afford a dark yellow oil which was purified by silica gel chromatography to afford the desired 2-amino-N- phenethyl-4-(trifluoromethyl)thiophene-3-carboxamide.

Preparation 32: 2-(2-Hvdroxy-phenvπ-5-methyl-3-phenethyl-3H-thienor2.3-dlpyrimidin-4- one

To a flask containing 3 mL of toluene was added 2-amino-N-phenethyl-4-

(trifluoromethyl)thiophene-3-carboxamide (Preparation 31 , 50 mg, 0.16 mmol), 2- methoxybenzaldehyde (32.5 mg, 0.23 mmol) and 4-toluenesulfonic acid (0.54 mg, 0.003 mmol). The reaction was heated to 120⁰C for twelve hours. The reaction was cooled and concentrated to afford an oil that was purified by silica gel chromatography to afford 30 mg of 2-(2-methoxyphenyl)-3-phenethyl-5-(trifluoromethyl)thieno[2,3-d]pyrimidin- 4(3H)-one (44% yield).

¹H NMR (CDCI₃) δ 7.73 (s, 1H), 7.37-7.42 (m, 1 H), 7.14-7.16 (m, 3H), 6.96-7.04 (m, 2H), 4.40 (m, 1H),3.79 (s, 3H), 3.77 (m, 1H), 3.01 (m, 1 H), 2.90 (m, 1H). MS m/z 431.3 (M+H)⁺.

Preparation 33: (ffl-5-amino-N-(1 -phenylpropan-2-yl)-3-(trifluoromethyl)isothiazole-4- carboxamide

L-Amphetamine hydrochloride (500 mg, 2.91 mmol) was taken up in 10 ml toluene and cooled to O⁰C. Trimethylaluminum (2.0M in toluene, 1.46 ml_, 2.91 mmol) was added and the solution was stirred at ambient temperature for 2 hours. Methyl 5- amino-3-(trifluoromethyl)isothiazole-4-carboxylate (329 mg, 1.46 mmol) was dissolved in 2 mL toluene and added and the reaction was heated at reflux for 1.5 hours. The reaction was cooled to ambient temperature and quenched with a 10 mL saturated solution of potassium sodium tartrate and stirred at ambient temperature for 1 hour. The mixture was diluted with 100 mL water and extracted with ethyl acetate (2 x 100 mL). Organic extracts were combined and washed with 50 mL each of water and brine and dried over Na₂SO₄. The salts were filtered and the filtrate concentrated under reduced pressure. The resultant clear oil was flash chromatographed with 20 % ethyl acetate/heptane to yield 280 mg (29.2%) of (R)-5-amino-N-(1-phenylpropan-2-yl)-3- (trifluoromethyl)isothiazole-4-carboxamide as a white foam. ¹H NMR (400 MHz, CDCI₃) δ 7.27 (t, 2H), 7.18 (m, 3H), 6.53 (brs, 2H), 5.92 (brs, 1 H), 4.35 (m(7), 1H), 2.89 (dd, 1 H), 2.72 (dd, 1H), 1.16 (d, 3H). MS m/z 330.2 (M+H)⁺.

Preparation of Compounds of Formula I

Example 1

Preparation of 2-Phenyl-5-trifluoromethyl-3-(2-thiazol-4-yl-ethyl)-3H-thienor2.3- dlpyrimidin-4-one

This example is representative of preparation of compounds of Formula I according to Reaction Scheme 1 and General Synthetic Procedure 1. 2-Thiazol-4-yl- ethylamine hydrochloride (0.176 g, 10.7 mmol) was added to the reaction mixture from Preparation 4 and then it was heated in a microwave at 250 ⁰C for 15 minutes. The reaction mixture was then cooled, concentrated in vacuo to give 1.723 g brown oil. The crude product was purified by flash chromatography using ethyl acetate:hexane mixture. The product obtained was then triturated with methanol, the solid was collected, washed with methanol and dried in vacuo to give 8 mg of final product. ¹H NMR (CDCI₃) δ 8.63 (d, 1 H), 7.69 (s, 1H), 7.38-7.42 (m, 1 H)₁ 7.05-7.25 (m, 3H), 4.45 (t, 2H), 3.49 (s, 3H), 3.33 (t, 2H). MS m/z 424.3 (M+H)⁺. Example 2

Preparation of 2-(2-Hvdroxy-phenyl )-5-trifiuoromethyl-3-phenethyl-3H-thieno[2.3- dipyrimidin-4-one

This example is representative of preparation of compounds of Formula I according to Reaction Scheme 2. Phenethylamine (0.07 ml_, 0.52 mmol) was added to the reaction mixture from Preparation 7 and then it was heated in a microwave at 250 ⁰C for 10 minutes. The reaction mixture was concentrated in vacuo to give 1.303 g of brown oil which was purified by flash chromatography, eluting with hexane/ethyl acetate mixture and then by preparative TLC plate eluting with chloroform to give 19 mg of final product. M.p. 239-240 ⁰C. ¹H NMR (CDCI₃) δ 7.73 (s, 1H), 7.37-7.42 (m, 1 H), 7.23 (s, 1H), 7.14-7.16 (m, 3H), 6.96-7.04 (m, 2H), 6.86-6.88 (m, 2H), 4.32 (t, 2H), 2.93 (t, 2H). MS m/z 417.3 (M+H)⁺.

Alternative Procedure For Preparation of Example 2: This example is representative of preparation of compounds of Formula I according to reaction Scheme 3. 1.0 M boron trichloride is added dropwise to a solution of 2-(2-methoxyphenyl)-3-phenethyl-5-(trifluoromethyl)thieno[2,3-d]pyrimidin-4(3H)-one (Preparation 32) in anhydrous methylene chloride at 0 ⁰C under an atmosphere of nitrogen for 0.5 hours. Methanol is added. The resulting solution is stirred at room temperature for 15 minutes and then the solvent is removed in vacuo. The residue is suspended in CHCI₃ and is washed with an aqueous solution of sodium potassium tartrate. The organic layer is collected, dried over magnesium sulfate, and concentrated in vacuo to afford crude product. The crude product is further purified by silica gel chromatography to 2-(2-Hydroxy-phenyl)-5-methyl-3-phenethyl-3H-thieno[2,3- d]pyrimidin-4-one, Example 2. Example 3

Preparation of 2-(2-Hvdroxy-phenyl)-3-phenethyl-5-phenyl-3/-/-thienof2.3-c/lpyrimidin-4- one

Prepared according to General Synthesis Procedure 1. MS m/z 425.1 (M+H)⁺.

Example 4 Preparation of 2-Cvclopentyl-3-phenethyl-3H-thienor2.3-(/lpyrimidin-4-one

Prepared according to General Synthesis Procedure 1. MS m/z 325.3 (M+H)⁺. Example 5

Preparation of 3-r2-(3-Fluoro-phenyl)-ethyll-2-(2-hvdroxy-phenyl)-6-methyl-5-jD-tolyl-3/-/- thienof2,3-d]pyrimidin-4-one

Prepared according to General Synthesis Procedure 1. MS m/z 471.1 (M+H)⁺.

Example 6

Preparation of 6-Benzyl-3-f2-(3-fluoro-phenvπ-ethvn-2-(2-hvdroxy-phenyl)-5-methyl-3/-/- thienor2.3-cπpyrimidin-4-one

Prepared according to General Synthesis Procedure 1. MS m/z 471.1 (M+H)⁺.

Example 7

Preparation of 3-r2-(3-Fluoro-phenyl)-ethvn-2-(2-hvdroxy-phenvO-5.6-dimethyl-3H- thienof2,3-cflpyrimidin-4-one

Prepared according to General Synthesis Procedure 1. MS m/z 395.1 (M+H)⁺.

Example 8

Preparation of 2-Cvclopentyl-3-phenethyl-5-trifluoromethyl-3H-thienor2.3-dlpyrimidin-4- one

Prepared according to the procedure of Reaction Scheme 2. MS m/z 393.3 (M+H)⁺.

Example 9

Preparation of 3-r2-(2-Fluoro-phenyl)-ethyll-2-(2-hvdroxy-phenyl)-5-trifluoromethyl-3H- thienor2.3-d1pyrimidin-4-one

.37 (m, 1 H), 7.21 (m, 1H), 7.10 (m,

1H), 8.87 (m, 1 H) 6.82 (m, 1H), 4.03 (t, 2H), 2.84 (t, 2H). MS m/z 435.2 (M+H)⁺. Example 10

Preparation of 2-(2-Hvdroxy-pyridin-3- yl )-3-phenethyl-5-trifluoromethyl-3H-thienor2.3- dlpyrimidin-4-one

¹H NMR (DMSOd₆) D 12.39 (s, 1H), 8.35 (s, 1H)₁ 7.67 (dd, 1H), 7.46 (dd, 1H), 7.20 (m, 3H), 6.90 (dd, 2H), 6.34 (t, 3H), 4.39 (m, 1 H), 3.74 (m, 1H), 2.94 (m, 1H), 2.79 (m, 1 H). MS m/z 418.5 (M+H)⁺. Example 11

Preparation of (ff)-2-(3-hvdroxypyridin-2-yl)-3-(1 -phenylpropan-2-vh-5-(triflurormethyl) thienoir2,3-d1pyrinidin-4-(3H)-one

¹H NMR (400MHz, cd3od), 8.195(dd), 8.184(d), 7.467(m), 7.131(m), 6.932(dd), 4.200(m), 3.365(m), 1.554(dd). LC/MS (M+1 ) 432.3.

Example 12

Preparation of 3-(2-fluorophenethyl)-2-(3-hvdroxypyridin-2-yl)-5- (trifluoromethyl)thienof2.3-dipyrimidin-4(3H)-one

1H NMR (CDCI₃) □ 3.30 (t,2H), 4.98 (t, 2H), 6.85 (t, 1H)₁ 7.0 (m, 1H), 7.19 (m, 1H), 7.22 (m, 1 H), 7.4 (m, 2H), 7.8 (s, 1 H), 8.3 (s, 1 H), 11.2 ( s, 1 HO MS m/z 436.2 (M+H)⁺. Example 13

Preparation of 3-(2-methoxyphenethyl)-2-(3-hvdroxypyridin-2-yl)-5- (trifluoromethyl)thienof2,3-c/lpyrirnidin-4(3/-/)-one

6.6 (d, 1H), 6.7 (t, 1H),6.9 (d, 1H),

7.1 (t, 1H), 7.21 (d, 2H), 7.75 (s, 1 H), 8.2 (s, 1H), 10.7 ( s, 1H) MS m/z 448.2 (M+H)⁺.

Example 14

Preparation of 3-(2-cvclohexylethyl)-2-(thiazol-4-yl)-5-(trifluoromethyl)thieno[2.3- dipyrimidin-4(3H)-one

¹H NMR (500 MHz, DMSO-cfe) D ppm 0.81 (t, 2H) 0.98 - 1.25 (m, 3 H) 1.42 - 1.75 (m, 8H) 4.13 - 4.28 (m, 2 H) 8.37 (s, 1 H) 8.46 (d, 1 H) 9.35 (d, 1 H). MS m/z 414.4 (M+H)⁺.

Example 15 Preparation of 2-(3-(2-cvclohexylethv0-4-oxo-5-(trifluoromethyl)-3.4-dihvdrothienor2.3- d1pyrimidin-2-yl)benzonitrile

¹H NMR (500 MHz, DMSO-cfe) □ ppm 0.65 (d, 2H) 0.86 (t, 1 H) 1.05 (d, 3H) 1.25 (br. s., 2 H) 1.30 - 1.44 (m, 3 H) 1.52 (br. s., 2 H) 3.85 (d, 2H) 7.80 - 7.86 (m, 1 H) 7.93 - 8.01 (m, 2 H) 8.14 (d, 1H) 8.44 (s, 1 H). MS m/z 432.4 (M+H)⁺.

Example 16

Preparation of 3-(2-cvclohexylethyl)-2-(2-hvdroxyphenyl)-5-(trifluoromethyl)thienor2.3- dlpyrimidin-4(3H)-one

¹H NMR (500 MHz, DMSO-Gf₆) □ ppm 0.64 (t, 2H) 0.94 - 1.12 (m, 4 H) 1.34 (d, 4H) 1.44 - 1.56 (m, 3 H) 3.89 (br. s., 2 H) 6.91 - 7.05 (m, 2 H) 7.33 - 7.47 (m, 2 H) 8.33 (s, 1 H) 10.22 (s, 1 H). MS m/z 423.4 (M+H)⁺.

Example 17

Preparation of 3-(2-cvclohexylethyl)-2-(3-hvdroxypyridin-2-yl)-5- (trifluoromethyl)thienof2.3-dipyrimidin-4(3H)-one

¹H NMR (500 MHz, DMSO-cfe) □ ppm 0.57 - 0.69 (m, 2 H) 0.96 - 1.14 (m, 4H) 1.34 (d, 2 H) 1.37 - 1.45 (m, 2H) 1.51 (d, 3 H) 3.78 - 3.92 (m, 2H) 7.38 - 7.54 (m, 2H) 8.20 (d, 1 H) 8.38 (s, 1H) 10.67 (s, 1 H). MS (LC-MS) 424.2 (M+H)⁺.

Example 18

Preparation of 6-(2-Hvdroxy-phenyl)-5-phenethyl-3-trifluoromethyl-5H-isothiazolo[5,4- dipyrimidin-4-one

1.0 M boron trichloride (0.50 mL) was added dropwise to a solution of 6-(2- methoxyphenyl)-5-phenethyl-3-(trifluoromethyl)isothiazolo[5,4-d]pyramid-4-one (Preparation 12, 45 mg, 0.10 mmol) in 1.0 mL of anhydrous methylene chloride at 0 ⁰C under an atmosphere of nitrogen for 0.5 hours. Methanol (1.0 mL) was added. The resulting solution was stirred at room temperature for 15 minutes and then the solvent was removed in vacuo to provide a white solid. The solid was suspended in CHCI₃ and was washed with an aqueous solution of sodium potassium tartrate. The organic layer was collected, dried over magnesium sulfate, and concentrated in vacuo to afford an off-white solid. This solid was further purified by silica gel chromatography to afford 7 mg (17% yield) of the desired 6-(2-Hydroxy-phenyl)-5-phenethyl-3-trifluoromethyl-5H- isothiazolo[5,4-d]pyrimidin-4-one. ¹H NMR (DMSO-d₆) δ 10.2 (s, H), 7.42 (m, 1 H)₁ 7.29 (d, 1 H), 7.15 (m, 3H), 7.00 (m, 2H), 6.72 (m, 2H), 4.00 (brS, 2H), 2.90 (brs, 2H). MS m/z 418.3 (M+H)⁺. Example 19

Preparation of 5-r2-(3-Fluoro-phenyl)-ethvn-6-(2-hvdroxy-phenyl)-3-trifluoromethyl-5H- isothiazolo[5,4-dipyrimidin-4-one

This example is representative of compounds of Formula I prepared according to Reaction Scheme 2. To the reaction mixture of Preparation 14, 3-fluorophenethylamine (117 mg, 0.84 mmol) was added and then the resulting mixture was microwaved at 250 ⁰C for fifteen minutes. The reaction mixture was concentrated and purified by silica gel chromatography to provide 77 mg (26% yield) of the desired 5-[2-(3-Fluoro-phenyl)- ethyl]-6-(2-hydroxy-phenyl)-3-trifluoromethyl-5H-isothiazolo[5,4-d]pyrimidin-4-one. ¹H NMR (DMSO) δ 7.40 (t, 1H), 7.20 (m, 2H), 6.99 (m, 3H), 6.24 (m, 2H), 4.0 (brs, 2H) 2.80 (m, 2H). MS m/z 436.4 (M+H)⁺.

Example 20 Preparation of 5-r2-(3-Fluoro-phenyl)-ethyl1-6-(2-hvdroxy-phenvπ-3-isopropyl-5H- isothiazolor5.4-dlpyrimidin-4-one

Prepared according to General Synthesis Procedure 1. MS m/z 410.1 (M+H)⁺.

Example 21 Preparation of 5-r2-(3-Fluoro-phenyl)-ethvn-6-(2-hydroxy-phenyl)-3-propylsulfanyl-5/-/- isothiazolor5,4-c/lpyrimidin-4-one

Prepared according to General Synthesis Procedure 1. MS m/z 442.1 (M+H)⁺. Example 22

Preparation of 5-r2-(3-Fluoro-phenyl)-ethyll-6-(2-hvdroxy-phenyl)-3-methyl-5/-/- isothiazolof5.4-(/lPyrimidin-4-one

Prepared according to General Synthesis Procedure 1. MS m/z 382.1 (M+H)⁺.

Example 23

Preparation of 5-r2-(2-Fluoro-phenyl)-ethvn-6-f2-hvdroxy-phenvπ-3-trifluoromethyl-5H- isothiazolor5.4-dipyrimidin-4-one

Prepared according to the procedure of Reaction Scheme 3. ¹H NMR (CDCI₃) δ 7.40

(m, 1 H), 7.20 (m, 3H), 6.99 (m, 2H), 6.89 (t, 1H), 4.4 (m, 2H), 3.10 (m, 2H). MS m/z

434.3 (M+H)⁺.

Example 24 Preparation of (R)-6-(2-Hvdroχyphenyl)-5-(1 -phenylpropan-2-yl-3-(trifluoromethvO isothiazolo[5.4-dlpyrimidin-4(5H)-one

Prepared according to the procedure of Reaction Scheme 3. ¹H NMR (CDCI₃) D 7.41 (m, 1 H), 7.09 (m, 3H), 6.99 (m, 3H), 6.78 (m, 2H), 4.64 (m, 1 H), 3.55 (dd, 1H), 3.04 (dd, 1H). MS m/z 430.2 (M-H)-.

Example 25

Preparation of 5-(3,4-Difluorophenethyl)-6-(2-hvdroxyphenyl)-3- (trifluoromethyl)isothiazolor5.4-dipyrimidin-4(5H)-one:

Prepared according to the procedure of Reaction Scheme 3. ¹H NMR (CDCI₃) D 7.48 (m, 1 H), 7.26 (m, 1 H), 7.10 (t, 1H), 7.02 (d, 1H), 6.96 (m, 1 H), 6.61 (m, 2H), 6.44 (brs), 4.30 (t, 2H), 2.87 (t, 2H). MS m/z 454.2 (M+H)⁺.

Example 26

Preparation of 6-(2-Hvdroxyphenyl)-5-phenethyl-3-(trichloromethyl)isothiazolof5,4- dlpyrimidin-4(5H)-one

Prepared according to General Synthesis Procedure 1. ¹H NMR (CDCI₃) D 7.46 (m, 1H), 7.23 (dd, 1H), 7.17 (m, 3H), 7.06 (m, 1H), 7.01 (d, 1H), 6.85 (m, 2H), 4.40 (m, 2H), 2.93 (m, 2H). MS m/z 466.0 (M+H-1)\ 468.1 (M+H+1)\ 470.1 (M+H+3)⁺.

Example 27

Preparation of (R)-6-(2-Hvdroxyphenyl)-4-oxo-5-(1-phenylpropan-2-yl)- isothiazolo[5.4- dlpyrimidine-3-carbonitrile

1.0M Boron trichloride in CH₂CI₂ (0.10 ml_, 0.10 mmol) was added dropwise to a solution of (R)-6-(2-Methoxyphenyl)-4-oxo-5-(1 -phenylpropan-2-yl)-isothiazolo[5,4- d]pyrimidine-3-carbonitrile (0.010 g, 0.03 mmol) in anhydrous CH₂CI₂ (3.0 mL) at 0° under N₂. The reaction mixture was warmed to room temperature and stirred at room temperature for 1 hour. Methanol (3.0 mL) was added to quench the reaction mixture then concentrated in vacuo to a brown residue. This was dissolved in CHCI₃ (3.0 mL) and washed with an aqueous solution of potassium sodium tartrate. The organic layer was separated and the aqueous layer was extracted with CHCI₃ (2 x 3.0 mL). The combined extracts were washed with water (3.0 mL), dried over MgSO₄ and evaporated in vacuo to give 0.012 g of tan solid. This material was purified by thin layer chromatography eluting with hexane/ethyl acetate to yield 0.005 g (50%) of the title compound. ¹H NMR (CDCI₃) D 7.42 (m, 1H), 7.13 (m, 3H), 6.98 (m, 2H), 6.82 (m, 2H), 4.61 (m, 1 H), 3.59 (dd, 1 H), 3.07 (dd, 1H), 1.86 (d, 3H). MS m/z 389.2 (M+H)⁺.

Example 28

Preparation of (R)-6-(3-hvdroxypyridin-2-yl)-5-(1 -phenylpropan-2-yl)-3- (trifluoromethyl)isothiazolor5.4-dlpyrimidin-4(5H)-one

Dissolved (f?)-5-amino-N-(1 -phenylpropan-2-yl)-3-(trifluoro-methyl) isothiazole-4- carboxamide (563 mg, 1.71 mmol) and 3-(benzyloxy)picolinaldehyde (437 mg, 2.05 mmol) and p-toluenesulfonic acid hydrate (3.25 mg, 17.1 mmol) in 4 mL DMAC and heated at 180⁰C for 30 min in microwave reactor. Reaction was cooled to ambient temperature and diluted with 50 mL ethyl acetate and washed with 50 mL brine. Brine layer was extracted with an additional 50 mL ethyl acetate and the combined organic extracts were dried over Na₂SO₄. The salts were filtered and the filtrate concentrated under reduced pressure. The resultant clear oil was flash chromatographed with 30% ethyl acetate/heptane and the product fractions were combined and concentrated under reduced pressure. Resultant oil was taken up in 5 mL DMF and treated with DDQ (543 mg, 2.39 mmol) at 90°C for 30 min. The reaction was cooled to ambient temperature and diluted with 50 mL brine and extracted with 2 x 50 mL ethyl acetate. The combined, organic extracts were dried over Na₂SO₄. The salts were filtered and the filtrate concentrated under reduced pressure. The resultant clear oil was flash chromatographed with 30% ethyl acetate/heptane and the product fractions were combined and concentrated under reduced pressure. Resultant oil was taken up in 15 mL 1 N HCI/acetic acid and heated in a sealed tube at 100⁰C for 18 h. The reaction was cooled to ambient temperature and volatiles were removed under reduced pressure. The resultant oil was diluted with 100 mL ethyl acetate and washed with 100 mL saturated aqueous NaHCO₃. Organic extract was dried over Na₂SO₄. The salts were filtered and the filtrate concentrated under reduced pressure. The resultant clear oil was flash chromatographed (12g silica, 0-50% EtOAc/heptane gradient) to yield 215 mg (29.1 %) of (R)-6-(3-hydroxypyridin-2-yl)-5-(1-phenylpropan-2-yl)-3-

(trifluoromethyl)isothiazolo[5,4-d]pyrimidin-4(5H)-one as a white powder. ¹H NMR (400 MHz, dmso-de) δ 10.75 (s, 1 H), 8.16 (dd, 1 H), 7.44 (m, 2H), 7.12 (m, 3H), 6.89 (d, 2H), 4.08 (brs, 1 H), 3.31 (m, 1H), 3.17 (dd, 1 H), 1.38 (d, 3H). MS m/z 433.1 (M+H^⁺ Example 29

Preparation of 5-(2-methoxyphenethyl)-6-(3-hvdroxypyridin-2-yl)-3-(trifluoromethyl) isothiazolof5.4-d1pyrimidin-4(5H)-one

Prepared analogous to Example 28. ¹H NMR (400 MHz, DMSOd₆) δ 10.72 (s, 1 H), 8.19 (dd, 1 H), 7.48 (m, 2H), 7.11 (t, 2H), 6.80 (m, 2H), 6.73 (t, 1 H), 3.99 (t, 2H), 3.75 (t, 2H), 3.45 (s, 3H). MS m/z 449.2 (M+H)⁺.

Example 30 Preparation of (ft)-5-(1 -cvclohexylpropan^-vD-δ-O-hvdroxypyridin^-vD-S- (trifluoromethyl) isothiazolo[5.4-d1pyrimidin-4(5H)-one

Prepared analogous to Example 28. ¹H NMR (CDCI₃) δ 8.32 (d, 1H), 7.43 (d, 1 H), 7.41 (m, 1H), 5.10 (m, 1H), 2.10 (m, 1H), 1.98 (m, 1H), 1.89 (d, 3H), 1.6-1.0 (m, 10H). MS m/z 439.3 (M+H)⁺.

Example 31

Preparation of 5-(2-cvclohexylethyl)-6-(3-hvdroxypyridin-2-yl)-3- (trifluoromethyl)isothiazolo [5.4-dipyrimidin-4(5H)-one

Prepared analogous to Example 28. ¹H NMR (CDCI₃) δ 11.1 (s, 1H), 8.32 (d, 1H), 7.43 (m, 2H), 4.70 (m, 1 H), 1.9-1.0 (m, 13H). MS m/z 425.3 (M+H)⁺. Example 32

Preparation of 5-(2-cvclohexylethyl)-6-(thiazol-4-vh-3-(trifluoromethyl)isothiazolor5.4- dlpyrimidin-4(5H)-one

5-(2-cyclohexylethyl)-6-isothiazole-3-(trifluoromethyl)-6,7-dihydroisothiazolo[5,4- d]pyrimidin-4(5H)-one (100 mg, 0.24 mmol) and dichlorodicyanobenzoquinone (81.8 mg, 0.36 mmol) were dissolved in 2 ml_ DMF and heated at 95⁰C for 1 hr. Reaction was cooled to ambient temperature and diluted with water. The solution was extracted (2X) with ethyl acetate and the combined organic extracts were dried over MgSO₄ and volatiles were removed under reduced pressure. The crude product was purified by silica gel chromatography to yield the desired product (30%). ¹H NMR (CDCI₃) δ 9.90 (s, 1 H), 8.20 (s, 1H), 4.45 (m, 2H), 1.80 (m, 7H), 1.2 (m, 4H), 0.99 (m, 2H). MS m/z 415.0 (M+H)⁺.

Example 33 Preparation of 5-(cvclohexylmethvO-6-(3-hvdroxypyridin-2-yl)-3- (trifluoromethvDisothiazolo r5.4-dlpyrimidin-4(5H)-one

Prepared analogous to Example 28. ¹H NMR (CDCI₃) δ 8.32 (d, 1H), 7.43 (m, 2H), 4.99 (m, 2H), 1.6-1.4 (m, 6H), 1.1 (m, 3H), 0.90 (m, 2H). MS m/z 411.0 (M+H)⁺. Example 34

Preparation of δ-cvclohexyl-e-O-hvdroxypyridin^-vπ-S-ftrifluoromethvDisothiazolorδΛ- d1pyrimidin-4(5H)-one

Prepared analogous to Example 28. ¹H NMR (CDCI₃) δ 8.30 (d, 1H), 7.43 (m, 2H), 4.70 (m, 1H), 2.81 (m, 2H), 2.0 (m, 2H), 1.90 (m, 2H), 1.5 (m, 2H), 1.10 (m, 2H). MS m/z 397.3 (M+H)⁺.

Example 35 Preparation of 5-r2-(3-Fluoro-phenyl)-ethvn-6-(2-hvdroxy-phenvh-3-methyl-5/-/- isoxazolo[5,4-c/lpyrimidin-4-one

Prepared according to General Synthesis Procedure 1. MS m/z 366.1 (M+H)⁺.

Example 36

Preparation of 6-(2-Hvdroxy-phenyl)-5-phenethyl-3-trifluoromethyl-5/-/-isoxazolor5.4- t/lpyrimidin-4-one

Prepared according to General Synthesis Procedure 1. MS m/z 402.2 (M+H)⁺. Example 37

Preparation of 5-r2-(3-Fluoro-phenyl)-ethvn-6-(2-hvdroxy-phenyl)-3-trifluoromethyl-5H- isoxazolof5.4-dipyrimidin-4-one

¹H NMR (CDCI₃) δ 7.48 (m, 1 H), 7.15 (m, 3H), 6.99 (d, 1H), 6.89 (m, 1 H), 6.65 (d, 2H), 6.5 (d, 1 H), 6.35 (brs, 1 H) 4.3 (t, 2H), 2.90 (m, 2H). MS m/z 418.3 (M+H)⁺. Example 38

Preparation of 6-(2-Hvdroxy-phenyl)-5-((R)-1 -methyl-2-phenyl-ethyl)-3-trifluoromethyl- 5H-isoxazolof5.4-d1pyrimidin-4-one

Example 39

Preparation of (R)-N-(2-(4-oxo-5-(1 -phenylpropan-2-yl)-3-(trifluoromethyl)-4,5- dihvdiOisoxazolof5.4-d1PVrimidin-6-yl)pyridin-3-yl)acetamide

This example is representative of preparation of compounds of Formula I according to Reaction Scheme 4. To a solution of (/?)-6-(3-aminopyridin-2-yl)-5-(1- phenylpropan-2-yl)-3-(trifluoromethyl)isoxazolo[5,4-d]pyrimidin-4(5H)-one (Preparation 20, 51 mg, 0.12 mmol) in DCM (2 mL) was added TEA (18.6 mg) and acetyl chloride (11.6 mg). The resulting mixture was stirred at room temperature overnight. The mixture was loaded on silica gel and purified by column chromatography to afford the title compound (21 mg, 37%). ¹H NMR (CDCI₃) δ8.63 (m, 1H), 8.45 (m, 1H), 8.17 (s, 1 H), 7.48 (m, 1H), 7.09 (m, 2H), 6.82 (m, 2H), 4.56(m, 1H), 4.12 (tetra, 7.1 Hz, 14.1Hz, 1 H), 3.68(dd, 10.0Hz, 13.7 Hz, 1 H), 2.96 (dd, 5.8Hz, 13.7Hz, 1H), 2.02 (s, 3H), 0.90(d, 6.6Hz₁ 3H). MS m/z 458.1(M+H)⁺. Example 40

Preparation of (ff)-N-(2-(4-oxo-5-(1 -phenylpropan-2-yl)-3-(trifluoromethyl)-4.5- dihvdroisoxazolor5,4-dlpyrimidin-6-yl)pyridin-3-yl)isobutyramide

This example is representative of preparation of compounds of Formula I according to Reaction Scheme 4. The title compound was prepared in the same manner as Example 39 using isobutyryl chloride instead of acetyl chloride. ¹H NMR (CDCI₃) δ 8.78 (s, 1H), 7.72 (m, 1H), 7.65 (m, 1H), 7.20 (m, 6H)₁ 4.26 (m, 1H), 3.73 (m, 1 H₁ 3.28 (m, 1 H), 2.80 (m, 1 H), 2.54 (tetra, 7.5HZ, 14.5 Hz, 1 H), 1.29 (m, 3H), 1.16 (m, 6H). MS m/z 484.1(M-H)⁺.

Example 41

Preparation of (R)-N-(2-(4-oxo-5-(1 -phenylpropan-2-yl)-3-(trifluoromethyl)-4.5- dihvdroisoxazolof5.4-dipyrimidin-6-yl)pyridin-3-yl)methanesulfonamide

This example is representative of preparation of compounds of Formula I according to Reaction Scheme 4. The title compound was prepared in the same manner as Example 39 using methane sulfonylchloride instead of acetyl chloride. ¹H NMR (CDCI₃) δ 8.51(dd, 1.7Hz, 4.6Hz, 1H), 8.11 (dd, 1.3Hz, 8.3Hz, 1H), 7.50 (dd, 4.6Hz, 8.7Hz, 1 H), 7.21 (m, 3H), 6.85 (m, 2H), 6.40 (s, 1 H), 4.41 (m, 1 H), 4.20 (m, 1 H), 3.67 (dd, 10.0 Hz, 13.7Hz, 1 H), 3.07 (s, 3H), 3.00 (dd, 5.8Hz, 13.7 Hz, 1H), 1.83 (d, 6.6Hz, 3H). MS m/z 494.2(M+H)⁺. Example 42

Preparation of (R)-2.2.2-trifluoro-N-(2-(4-oxo-5-(1 -Dhenylpropan-2-yl)-3-(trifluoromethvπ- 4.5-dihvdroisoxazolor5.4-cnpyrimidin-6-yl)pyridin-3-yl)acetamide

This example is representative of preparation of compounds of Formula I according to Reaction Scheme 4. To a cooled (-78"C) solution of (R)-6-(3-aminopyridin- 2-yl)-5-(1-phenylpropan-2-yl)-3-(trifluoromethyl)isoxazolo[5,4-d]pyrimidin-4(5H)-one (30 mg, 0.072 mmol) in DCM (2 ml) was added trifluoroacetic anhydride (30.3 mg, 0.144 mmol). The resulting mixture was stirred for 1 hour at -78°C. The reaction was quenched with 1 N HCI and the mixture was extracted with EtOAc. The combined organic layers were washed with NaHCO₃, brine and concentrated in vacuo to afford the titled compound (34mg, 92%). ¹H NMR (CDCI3) δ 9.71 (s, 1H), 8.68 (dd, 1.6Hz, 8.7Hz, 1H), 8.57 (dd.UHz, 4.6Hz, 1H), 7.56 (dd, 4.6Hz, 8.3Hz, 1H)₁ 7.02 (m, 3H), 6.70 (m, 2H), 4.69 (m, 1 H), 3.64 (m, 1H), 2.86 (dd, 5.0Hz, 13.7Hz, 1 H), 1.95 (d, 6.6Hz, 3H). MS m/z 512.1(M+H)⁺.

Example 43

Preparation of (ff)-6-(3-(methylamino)pyridin-2-yl)-5-(1 -phenylpropan-2-yl)-3- (trifluoromethyl)isoxazolof5.4-dipyrimidin-4(5H)-one

This example is representative of preparation of compounds of Formula I according to Reaction Scheme 4. (R)-6-(3-aminopyridin-2-yl)-5-(1-phenylpropan-2-yl)- 3-(trifluoromethyl)isoxazolo[5,4-d]pyrimidin-4(5H)-one (Preparation 20, 30 mg, 0.072 mmol) and formaldehyde (7.2mg 30% aq. solution, 0.072mmol) were mixed in DCE (2 ml), and then treated with sodium triacetoxyborohydride (61.2 mg, 0.289 mmol). The mixture was stirred at room temperature under N₂ overnight. The reaction mixture was quenched by adding aqueous saturated NaHCO₃, the product was extracted with EtOAc. The organic layer was dried over MgSO₄, filtered, concentrated in vacuo and the residue was purified by silica gel column chromatography (hexanes/ethyl acetate: 1/0 to 50/50 gradient in 15 minutes) to afford the title compound (12.5mg, 40%). ¹H NMR (CDCI₃) δ 8.03 (dd, 1.2Hz, 4.6Hz, 1H), 7.31 (dd, 4.6Hz, 8.7Hz, 1H), 7.11 (m, 3H), 7.06 (m, 1 H), 6.87 (m, 2H), 4.61 (m, 2H), 3.63 (dd, 9.5Hz, 13.7Hz, 1H), 3.03 (dd, 6.2Hz, 13.7Hz, 1 H), 2.77 (d, 5.0Hz, 3H), 1.80 (d, 6.6 Hz, 3H). MS m/z 430.1(M+H)⁺.

Example 44

Preparation of (ff)-6-(3-hvdroxypyridin-2-yl)-5-(1 -phenylpropan-2-yl)-3- (trifluoromethyl)isoxazolof5.4-d1pyrimidin-4(5H)-one

The titled compound was prepared from the corresponding benzyloxy precursor followed by the cleavage of benzyl group by heating the benzyl protected precursor in HCI/acetic acid solution (1 M) at 9O⁰C overnight. ¹H NMR (CDCI₃) 59.26 (s, 1 H), 8.32 (tetra, 2.1Hz, 4.2Hz, 1 H), 7.43 (m, 2H), 7.07 (m, 3H), 6.84 (m, 2H), 5.26 (m, 1 H), 3.57 (dd, 9.6Hz, 13.7Hz, 1 H), 3.12 (dd, 6.6Hz, 13.7 Hz, 1 H), 1.88 (d, 6.6 Hz, 3H). MS m/z 417.1(M+H)⁺.

Example 45 Preparation of 5-(2-fluorophenethyl)-6-(3-aminopyridin-2-yl)-3- (trifluoromethyl)isoxazolof5.4-dlpyrimidin-4(5H)-one

The following table provides FLIPR IC₅₀ data for the specified Examples. The IC_50S are reported as nanomolar concentration with n being the number of times the particular compound was assayed.

All documents cited in this application, including scientific publications, patents and patent applications, are hereby incorporated by reference in their entirety.

Claims

What is claimed is:

1. A compound of formula I

wherein

R¹ is Q or Q-(Ci-C₆)alkyl-; wherein the (d-C₆)alkyl portion of said Q-(Ci-C₆)alkyl- is optionally substituted with one to three substituents independently selected from fluoro, hydroxy or methoxy; R² is (CrC₆)alkyl, (C₃-C₇)cycloalkyl, aryl or heteroaryl; wherein said (Ci-C₆)alkyl, (C₃- C₇)cycloalkyl, aryl or heteroaryl is optionally substituted with one to three substituents independently selected from halo, cyano, hydroxy-fCrC^alkyl, (Ci-CβJalkyl, amino, (Cr Cβjalkylamino-, di(Ci-C₆)alkylamino-, (Ci-Cβjalkylcarboxamido-, (C-i- Cβjalkoxycarboxamido-, (Ci-C₆)alkylcarbonyl, (CrCβJalkylsufonamido-, (CrCβJalkoxy or hydroxy; wherein said (CrC₆)alkyl, (Ci-C₆)alkylamino-, di(Ci-C₆)alkylamino-, (Ci- C₆)alkylcarboxamido-, (CrCβJalkoxycarboxamido-, (CrCβJalkylcarbonyl, (C₁- C₆)alkylsulfonamido-, or (CrC₆)alkoxy substituent is optionally substituted independently with one to three halo; X is CR⁴ or N; Z is S or O; provided that Z is S when X is CR⁴; R³ is hydrogen, halo, (CrC₆)alkyl₍ (C₃-C₇)cycloalkyl, Q-(Ci-C₆)alkyl-, aryl, heteroaryl, cyano, OR⁵, SR⁵, NR⁶R⁷, C(O)R⁶, CO₂R⁶ or C(O)NR⁶R⁷; wherein said (d-C₆)alkyl, (C₃- C₇)cycloalkyl, aryl or heteroaryl is optionally substituted with one to three substituents independently selected from halo, cyano, trifluoromethyl, trifluoromethoxy, (Ci-Cβ)alkyl; (CrC₆)alkoxy, NR⁶R⁷ or hydroxy; R⁴ is hydrogen, halo, cyano, (Ci-C₆)alkyl optionally substituted with one to three fluoro, aryl, heteroaryl, or OR⁵;

R⁵ at each occurrence is independently (Ci-C₆)alkyl, (C₃-C₇)cycloalkyl, (C₃- C₇)cycloalkyl-(Ci-C₆)alkyl-, aryl, heteroaryl, aryl(CrC₆)alkyl-, or heteroaryl(Ci-C₆)alkyl-; each of said (Ci-C₆)alkyl, (C₃-C₇)cycloalkyl, (C₃-C₇)cycloalkyl-(C_rC₆)alkyl-, aryl, heteroaryl, aryl(Ci-C₆)alkyl-, or heteroaryl(Ci-C₆)alkyl- optionally substituted with one to three substituents independently selected from halo, hydroxy or (Ci-C₃)alkyl; R⁶ and R⁷, at each occurrence, are independently hydrogen, (Ci-C₆)alkyl, or (C₃- C₇)cycloalkyl; or R⁶ and R⁷ taken together with the nitrogen atom to which they are attached form a 3 to 7 membered fully saturated, partially saturated or fully unsaturated ring optionally containing one to two additional heteroatoms independently selected from N(R⁸)_n; O or S(O)_P; p is O, 1 or 2;

R⁸ is hydrogen or (C_rC₆)alkyl;

Q, at each occurrence, is independently (C₃-C₇)cycloalkyl, aryl or heteroaryl; wherein said aryl or heteroaryl is optionally substituted with one to three substituents independently selected from halo, cyano, trifluoromethyl, trifluoromethoxy, (Ci-Cβ)alkyl or (CrC₆)alkoxy; or a pharmaceutically acceptable salt thereof.

2. A compound of claim 1 wherein X is CR⁴ or a pharmaceutically acceptable salt thereof.

3. A compound of claim 1 wherein X is N and Z is S or a pharmaceutically acceptable salt thereof.

4. A compound of claim 1 wherein X is N and Z is O or a pharmaceutically acceptable salt thereof.

5. A compound of claim 2, 3 or 4, wherein R² is aryl or heteroaryl, wherein said aryl or heteroaryl is optionally substituted with one to three substituents independently selected from hydroxy, methyl, methoxy, (CrC₆)alkylcarboxamido- or halo; and wherein said (d-C^alkylcarboxamido- substituent is optionally substituted with one to three fluoro or a pharmaceutically acceptable salt thereof.

6. A compound of claim 5, wherein R² is 2-hydroxy-phenyl, 3-hydroxy- pyridin-2-yl or thiazolyl; wherein said 2-hydroxy-phenyl, 3-hydroxy-pyridin-2-yl or thiazolyl is optionally substituted with one fluoro or (CrC₆)alkylcarboxamido-; and wherein said (Ci-C₆)alkylcarboxamido- substituent is optionally substituted with one to three fluoro or a pharmaceutically acceptable salt thereof.

7. A compound of any of claims 1 , 2, 3, 4 or 6 wherein R¹ is Q-(Ci-C₄)alkyl-; wherein the (Ci-C₄)alkyl portion of said Q-(Ci-C₄)alkyl- is optionally substituted with one to three fluoro and Q is phenyl optionally substituted with one or two substituents independently selected from fluoro or methoxy or a pharmaceutically acceptable salt thereof.

8. A compound of claim 5 wherein R¹ is Q-(Ci-C₄)alkyl-; wherein the (C_r C₄)alkyl portion of said Q-(Ci-C₄)alkyl- is optionally substituted with one to three fluoro and Q is phenyl optionally substituted with one or two substituents independently selected from fluoro or methoxy or a pharmaceutically acceptable salt thereof.

9. A compound of claim 1 , wherein R¹ is phenethyl or 1-methyl-2- (phenyl)ethyl, wherein said phenethyl or 1 -methyl-2-(phenyl)ethyl is optionally substituted on phenyl with one or two halo and optionally substituted on the ethyl or 1- methylethyl moiety with one to three fluoro; R² is 2-hydroxy-phenyl or 3-hydroxy-pyridin- 2-yl, wherein said 2-hydroxy-phenyl or 3-hydroxy-pyridin-2-yl is optionally substituted with one methyl, methoxy, (Ci-Cβ)alkylcarboxamido- or fluoro; wherein said (Cr C₆)alkylcarboxamido- substituent is optionally substituted with one to three fluoro; R³ is (C_rC₃)alkyl, Q-(CrC₂)alkyl-, cyano or halo, wherein said (d-C₃)alkyl or Q-(Ci -C₂)alkyl- is optionally substituted with one to three halo; and R⁴ is hydrogen or methyl when X is CR⁴ or a pharmaceutically acceptable salt thereof.

10. A compound of claim 1 , wherein R³ is trifluoromethyl or cyano; and R⁴ is hydrogen or methyl when X is CR⁴ or a pharmaceutically acceptable salt thereof.

11. A compound of claim 10, wherein R² is aryl or heteroaryl, wherein said aryl or heteroaryl is optionally substituted with one to three substituents independently selected from hydroxy, methyl, methoxy, (Ci-C₆)alkylcarboxamido-, or fluoro; wherein said (CrC₆)alkylcarboxamido- substituent is optionally substituted with one to three fluoro or a pharmaceutically acceptable salt thereof.

12. A compound of claim 1 , wherein R¹ is phenethyl or 1-methyl-2- (phenyl)ethyl, wherein said phenethyl or 1-methyl-2-(phenyl)ethyl is optionally substituted on phenyl with one or two substituents independently selected from fluoro, methyl or methoxy; R² is 2-hydroxy-phenyl, 3-hydroxy-pyridin-2-yl or thiazolyl wherein said 2-hydroxy- phenyl, 3-hydroxy-pyridin-2-yl or thiazolyl is optionally substituted with one fluoro or (Cr C₆)alkylcarboxamido-; wherein said (Ci-C₆)alkylcarboxamido- substituent is optionally substituted with one to three fluoro; R³ is trifluoromethyl or cyano; and R⁴ is hydrogen when X is CR⁴ or a pharmaceutically acceptable salt thereof.

13. A compound selected from the group consisting of:

2-Phenyl-5-trifluoromethyl-3-(2-thiazol-4-yl-ethyl)-3H-thieno[2,3-d]pyrimidin-4-one; 2-(2-Hydroxy-phenyl)-5-trifluoromethyl-3-phenethyl-3H-thieno[2,3-d]pyrimidin-4-one; 2-(2-Hydroxy-phenyl)-3-phenethyl-5-phenyl-3H-thieno[2,3-c/Jpyrimidin-4-one;

2-Cyclopentyl-3-phenethyl-3H-thieno[2,3-c/]pyrimidin-4-one;

3-[2-(3-Fluoro-phenyl)-ethyl]-2-(2-hydroxy-phenyl)-6-methyl-5-p-tolyl-3H-thieno[2,3- d]pyrimidin-4-one;

6-Benzyl-3-[2-(3-fluoro-phenyl)-ethyl]-2-(2-hydroxy-phenyl)-5-methyl-3H-thieno[2,3- cflpyrimidin-4-one;

3-[2-(3-Fluoro-phenyl)-ethyl]-2-(2-hydroxy-phenyl)-5,6-dimethyl-3H-thieno[2,3- d]pyrimidin-4-one;

2-Cyclopentyl-3-phenethyl-5-trifluoromethyl-3/-/-thieno[2,3-c(lpyrimidin-4-one;

3-[2-(2-Fluoro-phenyl)-ethyl]-2-(2-hydroxy-phenyl)-5-trifluoromethyl-3H-thieno[2,3- d]pyrimidin-4-one;

2-(2-Hydroxy-pyridin-3-yl)-3-phenethyl-5-trifluoromethyl-3H-thieno[2,3-d]pyrimidin-4- one;

(R)-2-(3-hydroxypyridin-2-yl)-3-(1-phenylpropan-2-yl)-5-(triflurormethyl)thienol[2,3- d]pyrinidin-4-(3H)-one; 3-(2-fluorophenethyl)-2-(3-hydroxypyridin-2-yl)-5-(trifluoromethyl)thieno[2,3-d]pyrimidin-

4(3H)-one;

3-(2-methoxyphenethyl)-2-(3-hydroxypyridin-2-yl)-5-(trifluoromethyl)thieno[2,3- cθpyrimidin-4(3H)-one; 3-(2-cyclohexylethyl)-2-(thiazol-4-yl)-5-(trifluoromethyl)thieno[2,3-d]pyrimidin-4(3H)-one;

3-(2-cyclohexylethyl)-2-(2-hydroxyphenyl)-5-(trifluoromethyl)thieno[2,3-d]pyrimidin- 4(3H)-one;

4(3H)-one;

6-(2-Hydroxy-phenyl)-5-phenethyl-3-trifluoromethyl-5H-isothiazolo[5,4-d]pyrimidin-4- one; 5-[2-(3-Fluoro-phenyl)-ethyl]-6-(2-hydroxy-phenyl)-3-trifluoromethyl-5H-isothiazolo[5,4- d]pyrimidin-4-one;

5-[2-(3-Fluoro-phenyl)-ethyl]-6-(2-hydroxy-phenyl)-3-isopropyl-5H-isothiazolo[5,4- cflpyrimidin-4-one;

5-[2-(3-Fluoro-phenyl)-ethyl]-6-(2-hydroxy-phenyl)-3-propylsulfanyl-5H-isothiazolo[5,4- c(]pyrimidin-4-one;

5-[2-(3-Fluoro-phenyl)-ethyl]-6-(2-hydroxy-phenyl)-3-methyl-5/-/-isothiazolo[5,4- cdpyrimidin-4-one;

(R)-6-(3-hydroxypyridin-2-yl)-5-(1-phenylpropan-2-yl)-3-(trifluoromethyl)isothiazolo[5,4- d]pyrimidin-4(5H)-one; 5-(2-methoxyphenethyl)-6-(3-hydroxypyridin-2-yl)-3-(trifIuoromethyl)isothiazolo[5,4- d]pyrimidin-4(5H)-one;

(R)-5-(1-cyclohexylpropan-2-yl)-6-(3-hydroxypyridin-2-yl)-3-

(trifluoromethyl)isothiazolo[5,4-d]pyrimidin-4(5H)-one; 5-(2-cyclohexylethyl)-6-(3-hydroxypyridin-2-yl)-3-(trifluoromethyl)isothiazolo[5,4- d]pyrimidin-4(5H)-one;

5-(2-cyclohexylethyl)-6-(thiazol-4-yl)-3-(trifluoromethyl)isothiazolo[5,4-d]pyrimidin-4(5H)- one; 5-(cyclohexylmethyl)-6-(3-hydroxypyridin-2-yl)-3-(trifluoromethyl)isothiazolo[5,4- d]pyrimidin-4(5H)-one; δ-cyclohexyl-e^S-hydroxypyridin^-yO-S-^rifluoromethyOisothiazoloIS^-dlpyrimidin-

4(5H)-one;

5-[2-(3-Fluoro-phenyl)-ethyl]-6-(2-hydroxy-phenyl)-3-methyl-5H-isoxazolo[5,4- c(]pyrimidin-4-one;

6-(2-Hydroxy-phenyl)-5-phenethyl-3-trifluoromethyl-5/-/-isoxazolo[5,4-cdpyrimidin-4-one;

5-[2-(3-Fluoro-phenyl)-ethyl]-6-(2-hydroxy-phenyl)-3-trifluoromethyl-5H-isoxazolo[5,4- d]pyrimidin-4-one;

6-(2-Hydroxy-phenyl)-5-((R)-1-methyl-2-phenyl-ethyl)-3-trifluoromethyl-5H- isoxazolo[5,4-d]pyrimidin-4-one;

(/?)-N-(2-(4-oxo-5-(1-phenylpropan-2-yl)-3-(trifluoromethyl)-4,5-dihydroisoxazolo[5,4- d]pyrimidin-6-yl)pyridin-3-yl)acetamide;

(/?)-N-(2-(4-oxo-5-(1-phenylpropan-2-yl)-3-(trifluoromethyl)-4,5-dihydroisoxazolo[5,4- d]pyrimidin-6-yl)pyridin-3-yl)isobutyramide; (f?)-N-(2-(4-oxo-5-(1-phenylpropan-2-yl)-3-(trifIuoromethyl)-4,5-dihydroisoxazolo[5,4- d]pyrimidin-6-yl)pyridin-3-yl)methanesulfonamide;

(R)-2,2,2-trifIuoro-N-(2-(4-oxo-5-(1-phenylpropan-2-yl)-3-(trifluoromethyl)-4,5- dihydroisoxazolo[5,4-d]pyrimidin-6-yl)pyridin-3-yl)acetamide;

(R)-6-(3-(methylamino)pyridin-2-yl)-5-(1-phenylpropan-2-yl)-3- (trifluoromethyl)isoxazolo[5,4-d]pyrimidin-4(5H)-one;

(RJ-β^S-hydroxypyridin^-yO-δ-CI-phenylpropan^-ylJ-S-^rifluoromethyOisoxazolotδ^- d]pyrimidin-4(5H)-one; and

5-(2-fluorophenethyl)-6-(3-aminopyridin-2-yl)-3-(trifluoromethyl)isoxazolo[5,4- d]pyrimidin-4(5H)-one or a pharmaceutically acceptable salt thereof.

14. A pharmaceutical composition comprising a compound of claim 1 and a pharmaceutically acceptable carrier, adjuvant or diluent.

15. A method of treating osteoporosis, the method comprising administering to a patient in need of treatment thereof a therapeutically effective amount of a compound according to claim 22 or a pharmaceutically acceptable salt thereof or a pharmaceutical composition comprising a compound of claim 1 or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable carrier, adjuvant or diluent.