WO2015151068A1

WO2015151068A1 - Synthetic analogues of 3-iodothyronamine (t1am) and uses thereof

Info

Publication number: WO2015151068A1
Application number: PCT/IB2015/052458
Authority: WO
Inventors: Grazia Chiellini; Simona Rapposelli; Riccardo ZUCCHI
Original assignee: Universita' Di Pisa
Priority date: 2014-04-03
Filing date: 2015-04-03
Publication date: 2015-10-08

Abstract

Novel synthetic analogues of 3-iodothyronamine of formula (I), pharmaceutical compositions containing the same, and medical uses thereof are described.

Description

Synthetic analogues of 3-iodothyronamine (TI AM) and uses thereof

The present invention generally refers to synthetic analogues of thyroid hormones. More specifically, the invention relates to synthetic analogues of 3-iodothyronamine. pharmaceutical compositions comprising at least one of the said synthetic analogues of 3- iodothyronamine as the active ingredient in combination with a pharmaceutically acceptable carrier and/or excipient, as well as medical uses of the said synthetic 3- iodothyronamine analogues. 3-Iodothyronamine (TI AM) is an endogenous substance first identified in 2004 (Scanlan et al, Nat Med. 2004 Jun; 10(6):638-42. Epub 2004 May 16). It is a derivative of thyroid hormones, which with full rights may be regarded as a distinct hormone, as it is an endogenous compound that so far has been virtually identified in all tissues. It is also a potent agonist of membrane receptors known as "trace amine-associated receptors " (TAAR), which are expressed in many organs and until a few years ago were thought to be orphan receptors. TI AM was further suggested also to interact with other molecular targets, such as monoamine carriers, mitochondrial proteins and. at least in some tissues, with alpha-2-adrenergic receptors. But TI AM was not shown to be a ligand for nuclear receptors of thyroid hormones (TR). Finally, TI AM produces significant functional effects. The first effects to be observed consisted of a decrease in body temperature and heart contractility. Now we know that such effects occur at concentrations several orders of magnitude higher than the physiological ones. However, effects have been discovered which are detected at concentrations similar to the physiological ones, which are related to regulation of the metabolism and function of the central nervous system. Particularly, the literature shows that TI AM has an anti-insulin action, it favours the lipid catabolism over glucose metabolism and facilitates learning.

However, the most promising therapeutic application of TI AM is in the treatment of obesity. In fact, a recent experimental study described that chronic administration ( 1 week) of TI AM at a low dosage in experimental animals resulted in a significant decrease in body weight, without change in food intake, and glucose tolerance, The effect proved to be persistent at 2 weeks after treatment discontinuation, and is most likely linked to a complex expression modulation of proteins regulating homeostasis of glucose and lipids, such as sirtuins.

As extensively described in the literature, T I AM is rapidly metabolized by several enzymatic systems, such as: amine oxidases (MAO, SSAO), with formation of 3- iodothyroacetic acid; deiodinases (DI03), with formation of thyronamine; sulfotransferases (SULT 1 A 1 and SULT 1 A3); N-acetyltransferases; glucuronidases.

This obviously limits the possibilities of therapeutic uses of T I AM.

Accordingly, the development of synthetic T I AM analogues preferably provided with an enhanced biopharmacological profile and/or improved pharmacokinetic properties appears to be of fundamental importance for the purpose of an effective therapeutic application. In order to meet such a requirement, the present inventors synthesized a set of synthetic analogues of 3-iodothyronamine (T I AM) which, through a preliminary screening in experimental models available at the laboratories of these same inventors and previously used for studying the functional (isolated working rat heart) and metabolic (icv administration to mice) effects of T I AM, demonstrated an optimal mimicking of the effects induced by administration of TI AM or its endogenous derivative thyronamine (TOAM). These experiments are showed in detail in the section concerning the Examples. The results obtained show that the synthetic analogues of 3-iodothyronamine, which are the object of the present invention, are pharmaceutically effective active ingredients suitable to be used in treating diseases such as, for example, obesity, dyslipidemias, hypothyroidism (optionally in association with the thyroid hormone), neuropsychiatric disorders, behaviour disorders, cardiovascular disorders, hormone disorders such as, for example, Polycystic ovary syndrome (PCOS), ageing-related disorders.

The synthetic analogues of 3-iodothyronamine (T I AM) that form the subject of the present invention are represented by the following general formula (I):

wherein X is selected from O (oxygen) and CH₂;

n is an integer comprised between 0 (zero) and 3;

Z is selected from NH2, N0₂ and OR³; and

R² is selected from the group consisting of CH₂NH₂, CH₂NR R⁵, COOH, CN and COOR⁴; wherein R, R¹ , R³, R⁴ and R⁵ are independently selected from H and lower alkyl.

In the present description, the term "lower alkyl" is to be understood as a linear or branched alkyl group having from 1 to 4 carbon atoms, particularly methyl, ethyl, iso- propyl, n-propyl, iso-butyl, n-butyl, sec-butyl or tert-butyl.

Pharmaceutically acceptable salts of the compounds of formula (I) are also included in the scope of the present invention. Inorganic acids that can be used for obtaining pharmaceutically acceptable salts are, for instance, hydrochloric acid, phosphoric acid and sulfuric acid. Oxalates, tartrates, maleates, citrates and succinates are included among salts derived from the inorganic acids.

In a preferred embodiment of the invention, R and R¹ are both H.

In another preferred embodiment, R and R¹ are both methyl. In still another preferred embodiment, R is methyl and R¹ is H. In still a further preferred embodiment, n is zero or 1 .

In still another preferred embodiment, R² is CH₂NH₂ or COOH. Preferred compounds that fall within the scope of the present invention are listed hereinafter and are defined with reference to formula (I):

compound SG_1 , wherein R = R.' = H; X = 0; n = l ; Z = NH_2; R² = CH₂NH₂;

compound SG_2, wherein R = CH₃; R¹ = H; X = O; n = 1 ; Z = NH_{2 ;} R² = CH₂NH₂;

compound SG_3, wherein R = R' = H; X = 0; n = l ; Z = N0₂; R² = COOH;

compound SG_4, wherein R = CH₃; R¹ = H; X = O; n = 1 ; Z = N0₂; R² = COOH;

compound SG_5, wherein R = R' = H; X = 0; n = l ; Z = NH₂; R² - COOH;

compound SG_6, wherein R = methyl; R¹ = H; X = O; n = 1 ; Z = NH₂; R² = COOH;

compound SG_7, wherein R - R¹ - H; X = O; n = 1 ; Z = OH; R² = CH₂NH₂;

compound SG_8. wherein R = R¹ = H; X = CH₂; n = 0; Z = NH₂; R² = CH₂NH₂;

compound SG_9, wherein R = R¹ = H; X = CH₂; n = 0; Z = N0₂; R² = COOH; and compound SGJ 0, wherein R = R¹ = H; X = CH₂; n = 0; Z = NH₂; R² - COOH.

The synthesis of the said compounds is illustrated hereunder in the Examples section and more particularly in the reaction schemes 1 -4. Such reaction schemes illustrate general synthesis procedures that can be used for the synthesis of all compounds falling within the scope of the above-shown general formula (I).

The examples that follow are provided for illustrative purposes only and are not intended as limiting the scope of the invention, as defined in the appended claims.

EXAMPLES

Example 1 : synthesis of T1AM analogues according to the invention

The structure of the compounds was assessed by Ή-NMR and mass spectrophotometry. The most significant elements of the Ή-NMR and MS spectra were reported. All the synthesized compounds exhibit spectrum data in agreement with the assigned structures. The nuclear magnetic resonance spectra were performed with a Varian Gemini 200 MHz or Bruker TopSpin 3.2 400 MHz spectrometer; the solutions are approximately at 5% in CDC1 , CD₃OD or DMSO-d₆. The chemical shifts were expressed in ppms (δ scale). The melting points were determined under a Kolfler microscope and are uncorrected. The elemental analyses were carried out at the laboratory of Analytical Chemistry of the present inventors; the differences between the theoretical values and those obtained were comprised within a range of ± 0.4%. The evaporations were performed in a rotary evaporator and the dehydration of the organic phases was carried out by using Na₂SC>4. The analytical TLCs were performed by using MERCK silica gel (G60) plates with a 20 x 20.2 mm fluorescence indicator. The spots were detected by a UV lamp (256nm). For column chromatography, 70-230 mesh silica gel was used. For filtration through celite, celite * 521 was used.

SCHEME 1

Reagents and conditions: a: 4-Nitrobenzyl bromide, K2CO3, PdCl₂, Acetone/H₂0, r.t., 72 hrs; b: BBr₃, CH₂C1₂, 0°C. 1 hr; c: BrCH₂CN, DMF, Cs₂C0₃, r.t., 30 min; d: L1AIH4, AICI3, THF, reflux, 12 hrs.

Derivatives SG I and SG_2 were obtained by following the synthesis procedure shown in SCHEME 1. The cross-coupling reaction between p-nitrobenzyl bromide and the appropriate 4-methoxybenzeneboronic acid, using PdCl₂ as the catalyst and K₂C0₃ as the base, provided compounds la,b. The subsequent demethylation reaction in the presence of BBr₃ at 0°C resulted in the corresponding phenol derivatives 2a,b, which were subjected to an alkylation reaction with bromoacetonitrile to give the cyano derivatives 3a, b. The compounds were finally reduced with LiAlHj/AlCb into the final products SG_1 and SG_2

General procedure for the synthesis of derivatives la,b p-Nitrobenzyl bromide (569 mg, 2.63 mmoles) was added to a solution of the appropriate arylboronic acid (2.63 mmoles) in acetone/F O in a 1 : 1 ratio (4 ml), placed under N₂, and the resulting solution was stirred for 10 minutes. Thereafter, K₂C0₃ ( 1 .24 g, 6.58 mmoles) and a catalytic amount of PdCl₂ were added to this mixture. The mixture thus obtained was kept under stirring for 62 hours. After which, the solvent was evaporated and the aqueous layer was extracted with Et₂0. The organic layer was dried, filtered and evaporated. l-methoxy-4-(4-nitroben∑yl)benzene (la). The crude compound was purified by column chromatography, using an n-Hexane/AcOEt (97:3) mixture as the eluent. Yellow oil. (47% yield). Ή NMR (CDC1₃): δ 3.79 (s, 3H, OCH₃); 4.02 (s, 2H, CH₂); 6.86 (d, 2H, J = 8.3 Hz, Ar); 7.10 (d, 2H, J = 8.3, Ar); 7.32 (d, 2H, j=8.3 Hz, Ar); 8.13 (d, 2H, j=8.3 Hz, Ar) ppm. Anal. (C |₄H|₃N0₃) C, H, N. % Calc. 69.12 (C); 5.39 (H); 5.76 (N). % Obs. 69.12 (C); 5.39 (H); 5.76 (N).

4-methoxy-2-methyl- 1 -(4-nitrobenzyl)benzene (lb). The crude compound was purified by column chromatography, using an n-Hexane/AcOEt (97:3) mixture as the eluent. Yellow oil. (49% yield). Ή NMR (CDC1₃): δ 2.15 (s, 3H, CH₃); 3.78 (s, 3H, OCH₃); 4.01 (s, 2H, CH₂); 6.69-6.80 (m, 2H. Ar); 7.01 (s, 1 H, Ar); 7.23 (d, 2H. J =8.4 Hz, Ar); 8.10 (d. 2H, J = 8.4 Hz, Ar) ppm. Anal. (C ₁₅H, ₅N0₃) C, H, N. % Calc. 70.02 (C); 5.88 (H); 5.44 (N). % Obs. 70.22 (C); 5.93 (H); 5.62 (N).

General procedure for the synthesis of derivatives 2a, b

The derivative la,b is solubilized in the minimum amount of DCM, placed under N₂ at - 78°C. BBr₃ (3.94 mL, 1 .24 mmoles) is added dropwise to this solution. The reaction is stirred for 5 min at -78°C, and then kept at 0°C for 1 .5 hrs in an ice bath. Thereafter, the reaction is diluted with water and extracted with DCM. The organic layer is dried, filtered arid evaporated, to give compounds 2a,b. 4-(4-nitroben∑yl)phenol (2a). White oil. (95% yield). Ή NMR (CDC1₃): δ 4.00 (s, 2H, CH₂); 6.78 (d, 2H, J =7.5 Hz, Ar); 7.04 (d, 2H, J = 7.5 Hz, Ar) 7.32 (d, 2H, J=7.9 Hz, Ar); 8.14 (d, 2H, J=7.9 Hz, Ar) ppm. Anal. (C |₃H_nN0₃) C, H, N. % Calc. 68.1 1 (C); 4.84 (H); 6.1 1 (N). % Obs. 68.29 (C); 4.96 (H); 6.29 (N).

3-methyl-4-(4-nitroben∑yl)phenol (2b). Light yellow oil. (64% yield). Ή NMR (CDC1₃): δ 2.13 (s, 3H, CH₃); 4.00 (s. 2H, CH₂): 6.65-6.59 (m, 2H. Ar); 6.96 (s, 1 H, Ar); 7.24 (d, 2H, J=7.9 Hz. Ar); 8.1 1 (d, 2H, J=7.9 Hz, Ar) ppm. Anal. (C _uH,₃N0₃) C, H, N. % Calc. 69.12 (C); 5.39 (H); 5.76 (N). % Obs. 69.33 (C); 5.51 (H); 5.82 (N).

General procedure for the synthesis of derivatives 3a, b

The phenol derivatives 2a, b (100 mg, 0.44 mmoles) were solubilized in the minimum amount of DMF, Cs₂C0₃ (725 mg, 2.22 mmoles) was added till formation of the phenate. Then, BrCH₂CN (0.03 mL, 0.44 mmoles) was added to the reaction mixture. The reaction was stirred at r.t. for 30 min. Thereafter, a IN HC1 solution was added to the mixture, which was extracted with AcOEt. The combined organic layers were successively washed with a saturated NaCl solution and ice. The organic layer was dried, filtered and evaporated.

[4-(4-mtrobenzyl)phenoxy]acetonitrile (3a). The crude compound was purified by column chromatography, using an n-Hexane/ AcOEt (70:30) mixture as the eluent. White oil. (96% yield). Ή NMR (CDC1₃): δ 4.04 (s, 2H, CH₂); 4.76 (s, 2H, CH₂): 6.94 (d, 2H, J = 8.6 Hz, Ar); 7.15 (d. 2H, J = 8.6, Ar) 7.31 (d, 2H, J=8.6 Hz. Ar); 8.14 (d, 2H, J=8.6 Hz, Ar) ppm. Anal. (C ,₅H|₂N₂0₃) C, H. N. % Calc. 67.16 (C); 4.51 (H); 10.44 (N). % Obs. 67.24 (C); 4.72 (H); 10.62 (N).

3-[methyl-4-(4-nitroben∑yl)phenoxy]acetonitrile (3b). The crude compound was purified by column chromatography, using an n-Hexane/AcOEt (70:30) mixture as the eluent. White oil. (98% yield). Ή NMR (CDCI ): δ 2.19 (s, 3H, CH ); 4.04 (s, 2H, CH₂); 4.76 (s, 2H. CH₂); 6.81 -6.77(m, 2H, Ar); 7.08 (s. 1 H, Ar); 7.25 (d, 2H, J = 8.6 Hz, Ar); 8.13 (d, 2H, J - 8.6 Hz, Ar) ppm. Anal. (C 16H 14N2O3) C, H, N. % Calc. 68.07 (C); 5.00 (H); 9.92 (N). % Obs. 68.21 (C); 5.1 1 (H); 9.86 (N).

General procedure for the synthesis of derivatives SG I and SG 2.

A solution of 3a,b (0.34 mmoles) in THF was added to a solution of L1AIH4 (3.04 mmoles) and AICI3 (405 mg; 3.04 mmoles) in THF, placed under nitrogen, stirred at r.t. for 5 minutes. The reaction was stirred under reflux at 66°C for 12 hours. After this time, the mixture was cooled to 0°C, H₂0 was added, and the resulting mixture was acidified with a 10% HC1 solution. The mixture was then washed with Et₂0, the aqueous layer was alkalized with a 2N NaOH aqueous solution, and CHCI3 was added thereto. The resulting emulsion was filtered through a celite pad and the organic layer was finally washed with saturated NaCl, dried, filtered and evaporated under reduced pressure. 4-(4-(2-aminoethoxy)benzyl)aniline (SG_1). The crude compound was purified by formation of the hydrochloride. White solid. M.p.: 137- 135°C. (70% yield). Ή NMR (CD3OD): δ 3.35 (t, 2H, J = 5.0 Hz; CH₂); 3.98 (s, 2H, CH₂); 4.20 (t, 2H. J = 5.0 Hz; CH₂NH₂); 6.95 (d, 2H, J = 8,5 Hz, Ar); 7.16 (d, 2H. J = 8.5 Hz, Ar); 7.30 (d, 2H, J = 8.8 Hz, Ar); 7.37 (d, 2H, J = 8.8 Hz Ar) ppm. ^{I 3}C NMR (CD₃OD): δ 142.73, 139.53, 134.80, 130.20. 128.99, 128.70, 128.52. 122.73, 41 .04, 40.90, 32.70 ppm. Anal. (C ,_?H|₈N₂0) C, H. N. % Calc. 74.35 (C); 7.49 (H); 1 1 .56 (N). % Obs. 74.61 (C); 7.52 (H); 1 1 .73 (N).

4-(4-(2-aminoethoxy)-2-methylben∑yl)aniline (SG_2). The crude compound was purified by formation of the hydrochloride. White solid. M.p.: 156- 1 58°C. (75% yield). Ή NMR (CD3OD): δ 3.35 (t, 2H, J = 4.9 Hz; CH₃); 4.00 (s. 2H, CH₂); 4.21 (t, 2H, J = 4.9 Hz; CH2NH2); 6.79-6.88 (m. 2H, Ar); 7.09 (d. 1 H, J = 8.0 Hz, Ar); 7.23-7.34 (m, 4H, Ar) ppm. ^{I 3}C NMR (CD3OD): δ 156.92. 142.50, 137.92, 13 1 .37, 130.81. 129.87, 128.26, 122.61. 1 16.44, 1 1 1.64, 63.82, 39.00. 37.49, 18.52 ppm. Anal. (C |₆H₂oN₂0) C, H, N. % Calc. 74.97 (C); 7.86 (H); 10.93 (N). % Obs. 75.00 (C); 7.91 (H); 10.89 (N).

SCHEME 2

Reagents and conditions: a: BrCH₂COOEt, DMF, Cs₂C0₃, r.t, 30 min; b: NaOH 10%, MeOH, reflux, lhr; c: Hydrazine hydrate, Charcoal, FeCl₃, MeOH, reflux, 12 hrs.

Compounds SG 3 - SG_6 were synthesized by the procedure described in scheme 2. The alkylation reaction between the appropriate 2a,b phenol and ethyl -bromoacetate provided the corresponding ethyl esters 4a,b. The subsequent hydrolysis with 10% NaOH allowed for obtaining the SG_3 and SG_4 acids. The amine analogues SG_5 and SG_6 were obtained by reduction of the nitro group with hydrazine hydrate in the presence of FeCl₃ and charcoal.

General procedure for the synthesis of derivatives 4a, b The 2a,b phenol ( l OOmg, 0.44 mmoles), solubilized in the minimum amount of DMF, is reacted with BrCH₂COOEt (73.5mg, 0.44 mmoles). The synthetic procedure and the treatment of the reaction are analogous to those previously described for derivatives 3a, b.

Ethyl-2-(4-(4-nitroben∑yl)phenoxy)acetate (4a). Yellow oil. (83% yield). Ή NMR (CDCI3): δ 1 .27 (t, 3H, J =7.1 Hz, CH₃); 4.02 (s, 2H, CH₂); 4.27 (q, 2H, J =7.1 Hz, CH₂); 4.60 (s, 2H, CH₂); 6.86 (d, 2H, J = 8.4 Hz); 7.09 (d, 2H, J = 8.8 Hz); 7.31 (d, 2H, J = 8.8 Hz); 8. 13 (d, 2H, J = 8.4 Hz) ppm. Anal. (C ₇H_{1 7}NO5) C. H, N. % Calc. 64.75 (C); 5.43 (H); 4.44 (N). % Obs. 64.80 (C); 5.71 (H); 4.69 (N). Ethyl-2-(S- ethyl-4-(4-m(robenzyl)phenoxy)acetate (4b). Yellow oil. (60% yield). Ή NMR (CDC1₃): δ 1 .26 (t, 3H, J =7.0 Hz, CH₃); 2.12 (s, 3H, CH₃); 3.98 (s, 2H, CH₂); 4.23 (q, 2H, J =7.0 Hz, CH₂); 4.57 (s, 2H, CH₂); 6.32-6.79 (m, 2H, Ar); 6.97 (d, 1 H, J = 8.2, Ar) 7.21 (d, 2H, J =8.5 Hz, Ar); 8.08 (d, 2H, J = 8.5 Hz, Ar) ppm. Anal.

C, H, N. % Calc. 65.64 (C); 5.81 (H); 4.25 (N). % Obs. 65.91 (C); 5.93 (H); 4.39 (N).

General procedure for the synthesis of derivatives SG 3 and SG 4

A 10% NaOH solution (0.2 ml) was added to a solution of the ester derivative 4a,b (0.57 mmoles) in MeOH; the resulting solution was stirred under reflux for 30 minutes. Thereafter, the reaction mixture was set at 0°C, and H₂0 was added thereto; the precipitated solid was collected by filtration and washed with H₂0 giving the desired products. 2-(4-(4-Nitrobenzyl)phenoxy)acetic acid (SG_3). White solid. M.p.: 162-164°C. (87% yield). Ή NMR (CDC1₃): δ 4.02 (s, 2H, CH₂); 4.66 (s, 2H, CH₂); 6.88 (d, 2H, J = 8.4 Hz, Ar); 7.1 1 (d, 2H, J = 8.4 Hz, Ar); 7.31 (d, 2H, J = 8.4 Hz, Ar); 8.14 (d, 2H, J = 8.4 Hz, Ar) ppm. Anal. (0 ,₅Η,₃ΝΟ₅) C, H, N. % Calc. 62.72 (C); 4.56 (H); 4.88 (N). % Obs. 62.91 (C); 4.23 (H); 4.59 (N).

2-(4-(4-Nitrobenzyl)-3-methylphenoxy)acetic acid (SG_4). White solid. M.p.: 166-168°C. (90% yield). Ή NMR (CDC1₃): δ 2.17 (s, 3H, 4.02 CH₃), 4.02 (s, 2H, CH₂); 4.68 (s. 2H, CH₂); 6.70-6.80 (m, 2H, Ar); 7.03 (d, 1 H, J = 8.2, Ar); 7.24 (d, 2H, J =7.9 Hz, Ar); 8.12 (d, 2H, J =7.9 Hz. Ar) ppm. Anal. (C|₆H |₅N0₅) C, H, N. % Calc. 63.78 (C); 5.02 (H); 4.65 (N). % Obs. 63.87 (C); 5.21 (H); 4.51 (N).

General procedure for the synthesis of derivatives SG 5 and SG_6

Charcoal (33.7 mg) and FeCl₃ (7 mg) were added to a solution of the nitro derivative (0.64 mmoles) solubilized in the minimum amount of MeOH (4 ml). The reaction mixture was heated to reflux for 15 minutes, then a solution of hydrazine hydrate was added (0.33 ml, 6.71 mmoles), and the resulting mix was refluxed and agitated overnight. After this time, the mixture was filtered and the filtrate was evaporated. The residue was taken up with AcOEt and washed with H₂0; the organic layer was dried, filtered and evaporated.

2-(4-(4-Ammoben∑yl)phenoxy)acetic acid (SG_5). White solid. M.p. : 153- 155°C. (70% yield). Ή NMR (CDC1₃): δ 3.82 (s, 2H, CH₂); 4.54 (s. 2H, CH_:); 6.62 (d, 2H, J = 8.4 Hz, Ar); 6.81 (d, 2H, J = 8.4 Hz, Ar); 6.95 (d. 2H, J = 8.4 Hz, Ar); 7.1 1 (d, 2H, J = 8.4 Hz Ar) ppm. ^UC NMR (CDC1₃): δ 168.76, 1 55.34, 144.52, 135.92, 131 .22, 130.04. 129.65, 1 15.34, 1 14.49, 67.09, 40.14 ppm. Anal. (0 ,₅Η,₅ΝΟ₃) C, H, N. % Calc. 70.02 (C); 5.88 (H); 5.44 (N). % Obs. 70.39 (C); 5.93 (H); 5.59 (N).

2-(4-(4-Aminobenzyl)-3-methylphenoxy)acetic acid (SG_6). White solid. M.p.: 175-177°C. (65% yield). Ή NMR (CD₃OD): δ 2.16 (s, 3H, CH₃); 3.77 (s, 2H, CH₂); 4.36 (s. 2H. CH₂); 6.57-6.80 (m, 4H. Ar); 6.81 -6.89 (m, 2H. Ar) 6.92-7.01 (m, 2H. Ar) ppm. Anal. (C|₆H| ₇N0₃) C, H, N. % Calc. 70.83 (C); 6.32 (H); 5.16 (N). % Obs. 70.90 (C); 6.37 (H); 5.29 (N).

SCHEME 3

Reagents and conditions: a: Pd/C, AcOH. EtOH, r.t., 48 hrs; b: NaN0₂, H₂S0₄, H₂0, 100°C, 1 hr; c: L1AIH4, A1C1₃, THF, reflux. 12 hrs.

Compound SG_7 was synthesized by the procedure described in scheme 3. The catalytic hydrogenation of 3a by using Pd/C in concentrated AcOH provided the aniline derivative 5. which upon reaction with NaN0₂ in H₂S0₄ provided the phenol 6 through formation of the diazonium salt as the intermediate. Compound 6 was finally reduced with LiAlH /AlCl₃ into the final product SG_7.

Synthesis of derivative 5

2-(4-(4-Aminobenzyl)phenoxy)acetomtrile (5). A solution of the nitro derivative 3a (136 mg. 0.5 mmoles) in AcOEt was hydrogenated by using as the catalyst Pd/C (28.3 mg) and AcOH, for 48 hours at room temperature. After this time, the catalyst was filtered through celite and the solvent evaporated. The crude product 5 was used in the subsequent reaction without further purification. Yellow oil. (52% yield). Ή NM (CDCI₃) δ: 3.83 (s, 2H, CH₂); 4.73 (s, 2H, CH₂CN); 6.63 (d, 2H, J = 8.4 Hz. Ar); 6.89 (d, 2H, J =8.4 Hz, Ar); 6.95 (d, 2H, J = 8.4 Hz, Ar); 7.14 (d. 2H, J = 8.4 Hz, Ar) ppm. Anal. (C | ₅H₁₄N20) C, H, N. % Calc. 75.61 (C); 5.92 (H); 1 1.76 (N). % Obs. 75.70 (C); 6.07 (H); 1 1 .61 (N). Synthesis of derivative 6

2-(4-(4-Hydroxybenzyl)phenoxy)acetomtrile (6). To a suspension of the amino-derivative 5 (63,0 mg, 0.26 mmoles) in H₂0 (0.46 ml), under stirring, cone. H₂S0₄ (0,06 ml) was added dropwise. The mixture thus obtained was stirred at room temperature for 20 min. To this solution a NaN0₂ solution ( 17.9 mg, 0.26 mmoles) in H₂0 (0.19 ml) was added dropwise. The resulting solution was stirred at 100°C for 1 hr. After this time, the mixture was cooled, extracted with AcOEt. The organic layer was washed with NaCl, dehydrated, filtered and evaporated, to give the crude product 6. White solid. M.p.: 1 51 -1 53°C. (61 % yield). Ή NMR (CDCI3) δ: 3.87 (s, 2H, CH₂); 4.74 (s. 2H, CH₂CN); 6.76 (d, 2H, J - 8.4 Hz, Ar); 6.90 (d, 2H, J = 8.4 Hz, Ar); 7.02 (d. 2H, J = 8.4 Hz, Ar); 7.14 (d. 2H, J = 8.4 Hz, Ar) ppm. Anal. (C |₅H,₃N0₂) C, H, N. % Calc. 75.30 (C); 5.48 (H); 5.85 (N). % Obs. 74.92 (C); 5.48 (H); 6.13 (N).

Synthesis of derivative SG 7

4-(4-(2-Ami)ioethoxy)benzyi)phenol (SG_7). A solution of the cyano derivative 6 (32.3 mg; 0.13 mmoles) in THF was added to a LiAlH₄ ( l .2 l mmoles) and AICI3 (161 mg; l .2 l mmoles) solution in THF, under nitrogen, left stirring at r.t. for 5 minutes. The reaction was stirred under reflux at 66°C for 12 hours. Thereafter, the mixture was cooled to 0°C, H₂0 was added, and the resulting mix was acidified with 10% HCl. The solution was then washed with Et₂0, the aqueous layer was alkalized with 2N NaOH, and CHC1₃ was added thereto. The resulting emulsion was filtered through a celite pad, and the organic layer was finally washed with saturated NaCl, dehydrated, filtered and evaporated under reduced pressure, providing the crude product SG_7 which was purified by formation of the hydrochloride. White solid. M.p.: 175- 177°C. (50% yield). Ή NMR (CD₃OD): δ 3.34 (t. 2H, J = 4.8 Hz; CH₂); 3.80 (s, 2H, CH₂); 4.20 (t, 2H, J = 4.8 Hz; CH₂NH₂); 6.68 (d, 2H, J = 8.4 Hz, Ar); 6.91 (d, 2H, J = 8.8 Hz, Ar); 6.97 (d, 2H, J = 8.4 Hz, Ar); 7.1 1 (d, 2H, J = 8.8 Hz Ar) ppm. Anal. (C |₅H|₇N0₂) C, H, N. % Calc. 74.05 (C); 7.04 (H); 5.76 (N). % Obs. 74.31 (C); 7.22 (H); 5.73 (N).

SCHEME 4

7 8

d

e

9

SG 10 Reagents and conditions: a: KHF₂, MeOH/H₂0, r.t., 30 min; b: 4-Nitrobenzyl bromide, PdCl₂ dppf, Cs₂C0₃, H₂0/Dioxane, 95°C, 24 hrs; c: SOCl₂, CHCI3, r.t., 2hrs; d: NaCN, H₂0/CH₃CN, 100°C, 150 W, 8 bars, 4 x 20 min cycles; e: LiAlH , AICI3, THF, reflux, 12 hrs; f: H₂S0₄ 50%. reflux, 30 min; g: Hydrazine hydrate, Charcoal, FeCl₃, MeOH, reflux, 12 hrs.

Compounds SG_8, SG_9, SG_10 were synthesized by the procedure described in scheme 4. Through salification of the commercially available 4-hydroxymethylboronic acid with HF₂, the derivative 7 was obtained, which was cross-coupled with 4-nitrobenzyl bromide to give compound 8. The subsequent chlorination reaction in the presence of SOCl₂ provided the corresponding chloro-derivative 9, which by nucleophilic substitution with NaCN, gave the cyano-derivative 10. Reduction of 10 with L1AIH4 and in the presence of A1C1₃ provided the amino-compound SG_8, while its hydrolysis with H₂S0₄ allowed for obtaining the acid SG_9. The subsequent reaction of derivative SG_9 with hydrazine hydrate in the presence of FeCl₃ and charcoal provided the corresponding 4-(p- aminobenzyl)phenylacetic acid SG_10.

Synthesis of deriv ative 7 Potassium trifluoro[4-(hydroxymethyl)phenyl] -borate (7). KHF₂ (2.7 g; 34.2 mmoles) and a few drops of H₂0 were added to a solution of 4-hydroxymethyl-phenylboronic acid ( 1.3 g; 8.55 mmoles) in MeOH. The mixture was stirred at room temperature for 30 minutes. After this time, the solvent was evaporated and the solid obtained was purified by crystallization from iPrOH, to give the desired derivative 5. White solid. (63% yield). Ή NMR (CD₃OD): δ 4.53 (s, 2H. CH₂); 7.18 (d. 2H, J = 7.2 Hz, Ar); 7.48 (d, 2H, J = 7.2 Hz, Ar) ppm. Anal. (C7H7BF₃KO) C, H, N. % Calc. 39.28 (C); 3.30 (H). % Obs. 39.55 (C); 3.43 (H).

Synthesis of derivative 8

(4-(4-Nitroben∑yl)phenyl)methaiiol (8). p-Nitrobenzyl bromide (513 mg; 2.38 mmoles). cesium carbonate (2.30 g; 7.1 mmoles) and PdCl₂dppf (34.8 mg; 0.05 mmoles) were added to a solution of the salt 7 (509 mg; 2.38 mmoles) in dioxane/H₂0 in a 9: 1 ratio (17 ml), under nitrogen. The mixture thus obtained was stirred at 95°C for 24 hours. Thereafter, the organic solvent was evaporated and the aqueous layer extracted with CH2CI2. The organic layer was dried, filtered and evaporated, giving a crude product, which was purified by column chromatography by using an n-Hexane/AcOEt (70:30) mixture as the eluent. White oil. (32% yield). Ή NMR (CDC1₃): δ 4.08 (s, 2H, CH₂); 4.68 (s, 2H, CH₂OH); 7.17 (d, 2H, J = 8.0 Hz Ar); 7.34-7.32 (m, 4H, Ar); 8.14 (d, 2H. J= 8.4 Hz, Ar) ppm. Anal. (C |₄H,₃N0 ) C. H, N. % Calc. 69.12 (C); 5.39 (H); 5.76 (N). % Obs. 69.03 (C); 5.63 (H); 5.58 (N).

Synthesis of derivative 9 l-(Chloromethyl)-4-(4-mtrobemyl)benzene (9). SOCl₂ (0.009 ml) was added to a solution of 8 (86.4 mg; 0.35 mmoles) in CHCI3 at 0°C. The obtained mixture was stirred at room temperature for 2 hours. After this time, the solvent was evaporated and the obtained solid was taken up in H₂0 and alkalized with IN NaOH; the aqueous layer was extracted with CH2CI2. The organic layer was dried and evaporated to give the desired crude product 9 which was used in the subsequent reaction without further purification. Yellow oil. (83% yield). Ή NMR (CDC1₃): δ 4.08 (s. 2H, CH₂); 4.57 (s, 2H, CH₂); 7.1 7 (d, 2H. J = 8.0 Hz, Ar); 7.35-7.32 (m, 4H, Ar); 8.15 (d. 2H, J = 8.8 Hz Ar) ppm. Anal. (C 14H 12CINO2) C, H, N. % Calc. 64.25 (C); 4.62 (H); 5.35 (N). % Obs. 63.96 (C); 4.46 (H); 5.71 (N).

Synthesis of derivative 10 2-(4-(4-Nitrobenzyl)phenyl)acetowtrile (10). NaCN (57.0 mg; 1 .16 mmoles) in H₂0 (0.26 ml) was added to a solution of derivative 9 (152 mg; 0.58 mmoles) in CH3CN (0.78 ml). The mixture thus obtained was placed in a microwave oven, setting the following parameters: temperature 100°C; power 150 W; pressure 8 bars; time 20 minutes. After cooling, the reaction mixture was extracted with CH₂C1₂ and the organic layer was dried and evaporated under reduced pressure, obtaining the desired crude product 10. Yellow oil. (86% yield). Ή NMR (CDCI3): δ 3.73 (s, 2H, CH₂), 4.08 (s, 2H, CH₂); 7.19 (d, 2H, J = 8.0 Hz; Ar); 7.33-7.28 (m. 4H. Ar); 8.15 (d, 2H, J = 8.8 Hz; Ar) ppm. Anal. (C |₅H|2N₂0₂) C, H, N. % Calc. 71 .42 (C); 4.79 (H); 1 1 .10 (N). % Obs. 71 .56 (C); 4.64 (H); 1 1 .33 (N).

Synthesis of derivative SG_8

4-(4-(2-Aminoethyl)benzy\)aml\ne (SG_8). A solution of the cyano derivative 10 (85.0 mg; 0.34 mmoles) in THF was added to a LiAlH₄ (3.04 mmoles) and A1C1₃ (405 mg; 3.04 mmoles) solution in THF, placed under nitrogen, left stirring at room temperature for 5 minutes. The reaction was stirred under reflux at 66°C for 12 hours. After this time, the mixture was cooled to 0°C, H₂0 was added, and the resulting mix was acidified with 10% HC1. The solution was then washed with Et₂0, the aqueous layer was alkalized with 2N NaOH, and CHCI₃ was added thereto. The resulting emulsion was filtered through a celite pad and the organic layer was finally washed with saturated NaCl, dried, filtered and evaporated under reduced pressure, to give the crude product SG_8 which was purified by formation of the hydrochloride. White solid. M.p.: 165-167°C. (70% yield). Ή NMR (CD3OD): δ 2.93 (t. 2H. J = 7.8 Hz; CH₂); 3.15 (t, 2H, J - 7.8 Hz; CH₂); 4.02 (s, 2H, CH₂); 7.25-7.20 (m, 4H, Ar); 7.33 (d, 2H,J = 8.4 Hz. Ar) 7.38 (d, 2H, J = 8.4 Hz, Ar) ppm. ¹³C NMR (CD₃OD): 5 142.83, 139.53, 134.58, 130.20, 129.12, 128.67, 128.50, 122.71 , 40.54, 40.30. 32.75 ppm. Anal. (C ,₅H|₈N₂) C. H, N. % Calc. 79.61 (C); 8.02 (H); 12.38 (N). % Obs. 79.45 (C); 8.18 (H); 12.77 (N).

Synthesis of derivative SG_9

2-(4-(4-Ni(roben∑y )p enyl)ace(ic acid (SG_9). A solution of 10 (51 .6 mg; 0.20 mmoles) in 50% H2SO₄ (0.2 ml) was stirred under reflux for 30 minutes. After this time, the reaction mixture was set at 0°C, and H₂0 was added thereto; the precipitated solid was collected by filtration and washed with H₂0, providing the desired product SG_8. Yellow solid. M.p.: 175- 1 77°C. (79% yield). Ή NMR (CDCI3): δ 3.58 (s, 2H. CH₂); 4.09 (s, 2H, CH₂); 7.19 (d, 2H, J = 7.6 Hz, Ar); 7.37-7.27 (m, 4H, Ar); 8.17 (d, 2H, J = 7.6 Hz, Ar) ppm. Anal. (C 15H13NO₄) C. H, N. % Calc. 66.41 (C); 4.83 (H); 5.16 (N). % Obs. 66.44 (C); 4.55 (H); 5.28 (N). Syothesis of derivative SG_10

2-(4-(4-Aminoben∑yl)phenyl)acetic acid (SG_10). Charcoal (33.7 mg) and FeClj (7 mg) were added to a solution of compound SG_8 (167 mg; 0.64 mmoles) solubilized in the minimum amount of MeOH (4 ml). The reaction mixture was heated under reflux for 15 minutes, then a hydrazine hydrate solution (0.33 ml, 6.71 mmoles) was added thereto, and the reaction was refluxed with stirring overnight. Thereafter, the mixture was filtered and the filtrate was evaporated. The residue was taken up with AcOEt and washed with H₂0; the organic layer was dried, filtered and evaporated, obtaining a crude product, which was purified by formation of the hydrochloride. White solid. M.p. : 154- 156°C. (72% yield). Ή NMR (CD₃OD): δ 3.61 (s, 2H, CH₂); 4.01 (s, 2H, CH₂); 7.19 (d, 2H, J = 8.0 Hz, Ar); 7.26 (d, 2H. J = 8.0 Hz, Ar); 7.31 (d, 2H, J = 8.4 Hz, Ar); 7.37 (d, 2H, J = 8.4 Hz, Ar) ppm. Anal. (C 15H 13NO4) C. H. N. % Calc. 66.41 (C); 4.83 (H); 5.16 (N). % Obs. 66.12 (C); 5.18 (H); 5.09 (N).

Example 2: cardiac effects

The cardiac effects of thyronamine analogues falling within the scope of the present invention were assessed in acute treatment models.

The experimental model used is the isolated perfused rat heart with the working heart technique (Zucchi R, Ronca-Testoni S, Yu G, Galbani P, Ronca G, Mariani M. Effect of ischemia and reperfusion on cardiac ryanodine receptors - sarcoplasmic reticulum Ca²⁺ channels. Circ Res 1994: 74:271 -280), which allows for monitoring the main haemodynamic variables, such as: aortic flow, coronary flow, cardiac output, heart rate, aortic pressure.

After anaesthesia with a mixture of ether/air, the hearts of Sprague-Dawley rats (275-300 g of weight) were removed and perfused by using the working heart apparatus, in which the preload (height of the atrial chamber) and the afterload (height of the aortic chamber) were set at heights of 20 and 70 cm. respectively. The aortic and coronary flows were measured by collecting the perfusion liquid from the aortic and atrial chambers, respectively, into a graduated cylinder. The cardiac output was determined as the sum of the aortic and coronary flows. The perfusion medium was the rebs-Henseleit buffer solution (pH 7.4), which has the following composition (mmol/L): NaCl 1 1 8, NaHC0₃ 25, C1 4.5, H₂P0₄ 1 .2, MgS0₄ 1 .2, CaCl₂ 2.5, and glucose 1 ). The perfusion medium was kept in recirculation by a mechanical pump and was equilibrated with an 0₂ (95%)/C0₂ (5%) mixture. The temperature was maintained constant throughout the experiment at 37-37.4°C. After a 10 min equilibration time, the compounds (SG I and SG 2) were added to the perfusion medium, at concentrations within the range of from 100 nM to 100 microM, and the haemodynamic variables were monitored for 60 min.

As shown in Figure 1 , both compounds produced a dose-dependent negative inotropic effect (decrease in the cardiac output), with IC50 values (SG I , ^50= 0 microM; SG_2, IC50=20 microM) comparable to those obtained in previous experiments with administration of thyronamine (T0AM) and 3-iodothyronamine (T1 AM) [Scanlan et al, Nat Med 2004; 10: 638-642; Chiellini et al, FASEB J 2007; 21 , 1 597- 1608], The concentration-response curves for the effects of analogues SG_1 and SG_2 on the cardiac output are shown in Figure 1 .

Example 3: metabolic effects In male mice (CD 1 , weighing 25.2 +/- 3.2 g; Harlan-Nossan (Italy) fasted for 4 hrs before being subjected to an i.c.v injection (Manni et al, Br J Pharmacol 2013; 168(2):354-362) with saline (controls) or with one of the test compounds (T l A at doses of 1 .32 microgrKg- 1 and 4 microgrKg- 1 ; T0AM, T1 AM and SG I at 1 .32 microgrKg- 1 ), the glucose levels were measured in blood collected from the venous vessels of the tail. As shown in Figure 2, SG- 1 administered i.e. v. at 1 .32 microgr g- 1 was capable of producing a significant increase in plasma glucose, which was fully comparable to the one produced by the structurally analogous endogenous thyronamine (TOAM). Figure 2 shows the effects of SG I on glycaemia.

Example 4: agonistic TAAR 1 activity

In order to assess the effectiveness of the molecular design of the new SG set of compounds, such as novel analogues for TAAR1 receptors, HEK-293 cells transfected with the murine TAAR 1 receptor (mTAAR l ) were examined for the induction of cAMP production by the BRET (Bioluminescence Resonance Energy Transfer) technique according to the method described in literature (Espinoza S, Salahpour A, Masri B, Sotnikova TD, Messa M, Barak LS, Caron MG, Gainetdinov RR. Functional interaction between trace amine-associated receptor 1 and dopamine D2 receptor. Mol Pharmacol. 201 1 ; 80(3):416-25). After a first screening at 10 microM, the active compounds were used in dose-response experiments. As shown in Figure 3, the preliminary results demonstrated that the presence of an oxyethyl- or ethyl-amine chain at position 1 is critical for the occunence of the agonistic mTAARl activity, and compound SG 2 appears to be the most potent among the test compounds (SG I , 2, 7, 8) with an EC50 = 240 nM. Compound SG 8, although less potent than SG_2 (EC50 = 800 nM), appears to be the most effective among the tested set, with Emax = 100%, as calculated in comparison with the effect of 10 microM beta-phenylethylamine, which is the reference agonist for TAAR1 receptors. Figure 3 shows the dose-response curves for activation of mTAAR l . Particularly, it shows the differential cAMP levels by using the cAMP BRET biosensor in HE -293T cells that express mTAARl . The values on the Y-axis in each panel denote the Rluc/YFP ratio, which is known as the BRET ratio. The table that follows shows the preferred compounds of the present invention.

Claims

1 . A compound of formula (I):

wherein X is selected from O (oxygen) and CH2 ;

n is an integer comprised between 0 (zero) and 3;

Z is selected from NH₂, N0₂ and OR³;

R² is selected from the group consisting of CH₂NH₂, CH₂NR⁴R^"\ COOH, CN and COOR⁴; wherein R, R¹ , R³, R⁴ and R⁵ are independently selected from H and a linear or branched alkyl group having from 1 to 4 carbon atoms and pharmaceutically acceptable salts thereof.

2. The compound according to claim 1 , wherein said pharmaceutically acceptable salts are selected from the group consisting of hydrochlorides, phosphates, sulfates, oxalates, tartrates, maleates, citrates and succinates.

3. The compound according to claim 1 or 2, wherein R and R¹ are both H.

4. The compound according to claim 1 or 2, wherein R and R¹ are both methyl.

5. The compound according to claim 1 or 2, wherein R is methyl and R is H.

6. The compound according to any one of claims 1 to 5, wherein n is zero or 1 .

7. The compound according to any one of claims 1 to 6, wherein R² is CH2NH2 or

COOH.

8. The compound according to claim 1 , which is selected from the group consisting of: compound SG_ 1 , wherein R = R' = H; X = 0; n = l ; Z = NH_2; R² = CH₂NH₂; compound SG_2, wherein R = CH₃; R¹ = H; X = O; n = 1 ; Z = NH_2; R² = CH₂NH₂;

compound SG_3. wherein R = R' = H; X = 0; n = l ; Z = N0₂; R² = COOH;

compound SG_5, wherein R = R' = H; X = 0; n = l ; Z = NH₂; R² - COOH:

compound SG_7, wherein R = R¹ = H; X = O; n = 1 ; Z = OH; R² = CH₂NH₂;

compound SG_8. wherein R = R¹ = H; X = CH₂; n - 0; Z = NH₂; R² = CH₂NH₂;

compound SG_9, wherein R = R¹ = H; X = CH₂; n = 0; Z = N0₂; R² = COOH; and compound SGJ O, wherein R = R¹ = H; X = CH₂; n - 0; Z = NH₂; R² = COOH.

9. The compound according to any one of claims 1 to 8, for use as a medicament.

10. The compound according to any one of claims 1 to 8, for use in the therapeutic treatment of a disease selected from the group consisting of obesity, dyshpidemias, hypothyroidism (optionally in association with the thyroid hormone), neuropsychiatric disorders, behaviour disorders, cardiovascular disorders, hormone disorders such as, for example, Polycystic ovary Syndrome (PCOS), ageing-related disorders.

1 1 . A pharmaceutical composition comprising at least one compound according to any one of claims 1 to 8 and a pharmaceutically acceptable carrier and/or excipient.