IE55819B1 - Substituted peptide compounds - Google Patents

Description

Substituted Peptide Compounds This invention is directed to compounds which may be useful in the preparation of substituted peptide compounds of formula 1 and salts thereof (I) O R R, O ll I I1 I R--CH-C-CH,—N - CH - C-X I . (X.) NH I C-0 I X is an amino or imino acid of the formula H, R, -N — C-COOR, N—C-COORlit) 6 •n — c-ow, I (I·) H ..... _2_ Rl0><R10 fH2 -N-C-COOR.

I (M 1 H tv-jr*: -N—C-COORI (M 6 R -N— C-COcAZ.

I (L) H or. -N -CH-COOR. ί I Rg Rj.· -3Rj Is hydrogen, lower alkyl, halogen, keto, R-ft Z 19 hydroxy, -NH-C-lower alkyl, azido, amino, -N^. · -«ν.-®. .

P 13»p a 1- or 2-naphthyl of the formula IS , -(CH2)m-cycloalkyl, RU>p O-C-N -0-lower alkyl, -0- ' (Κ13^ a 1- or 2-naphthyloxy of the formula -o-tcspfl ^δχδ> , -S-lower alkyl. l<*p -S-ICH2) or a 1- or 2-naphthylthio of the formula -4Rft Is keto, halogen·, | /R15 -0-0 * * 3 j-/q\ , -O-lower alkyl <R13>p 2-naphthyloxy of the formula -S-lower alkyl. -S-ICHjJjj-ZqX Y-ZNRljlp or a 1- or 2—naphthylthlo of the formula -S-CCHj)^ Foioj- <Ru’P Rg Is keto or '©•ο .

(R13'p Rgg is halogen or -Y-Rgg. *11' il , Rg2 and R’l2 are independently selected from hydrogen and lower alkyl or R·χχ , Rg2 and R’gg are hydrogen and Rgg is Rg3 is hydrogen, lower alkyl' of 1 to 4 carbons, lower alkoxy of ,1 to 4 carbons, lower alkylthio of 1 to 4 carbons, chloro, bromo, fluoro, trifluoromethyl, hydroxy, phenyl, phenoxy, phenylthio, or phenylmethyl· Rg4 is hydrogen, lower alkyl of 1 to 4 carbons, lower alkoxy of 1 to 4 carbons, lower alkylthio of 1 to 4 carbons, chloro, bromo, fluoro, trifluoromethyl, or hydroxy· m is zero, one, two, three, or four, p is one, two.or three provided that p is more than one only if Rg3 or Rgg is hydrogen, methyl, methoxy, chloro, or fluoro.

RgS is hydrogen or lower alkyl of 1 to 4 carbons.

Y is oxygen or sulfur.

R16 ie lower alkyl of 1 to 4 carbons. or the Rgg groups join to complete an unsubstituted 5- or €-membered* ring -6or said ring in which one or more of the carbons has a lower alkyl of 1 to 4 carbons or a di (lower alkyl of 1 to 4 carbons) substituent.

R. is hydrogen, lower alkyl, 4 -(ch2) -(d^-cycloalkyl, , -(0¾)^ , (CH,) ' * Ό0 · °r ~C(o) · Rg is hydrogen, lower alkyl,- -r iCB2Yr^)~OB· -(CH2)r-OH, -(CHjjJjr^OH OH -(¾ -(CH2)r-NH2, -(ΟΗ2)Γ-5Η, -(CH2)r-s-lower alkyl.

NH — (CH.) -NH-C 2 r D or -(CH2)r-C-NH2 NH -7Γ ... r is an integer from 1 to 4.

R^g la lower alkyl', benzyl, or phenethyl. K20 is hydrogen, lower alkyl, benzyl or phenethyl.

R Is hydrogen, lower alkyl, cycloalkyl. -(ch2)2-nh2, -(ch2)3-nh2 , - (ch2)4-nh2, -2)2-oh, -(ch2)3-oh, - (CH2)4-OH, -(CH2)2-SH, -(CH2)3-SH, or -2)4-SH.

Rj is hydrogen, lover alkyl,*halo substituted lower alkyl, .

-(CH2’r@ ' . -(.αψί-y-jg) OH 7 -(CH,) 2' r * (CHj) x-NU2 , - (CHj) xSH, ’lca2*r“0H' -ic*2lrs’lower30 -r-NH-C NHj , or '(.CHj)r-C-NH2 -Mprovided th#t is'hydrogen only if R is other than hydrogen·.

R2 is -‘CH2’ir®l(R , ' -2,iH0) |RHTp ks ' or -(CH2) Rg is hydrogen, lower alkyl. 14'P (CHg)· -(CHg)^-^^J ' halo substituted lower alkyl, -(CHg)n-cycloalkyl, (CHg)p^^-OH , (CH.

,;TC® «μ2)γ-οη.

-(CH,) -ΒΙΟ -lcH2)r-NH2, -lCH2)r-SH, -2)r-S-lower alkyl, NH O Λ ' -(eH2)r-NH-C X .or -(CH2)r-C-NH2 ^nh2 wherein n, P and'r are as defined above.

Rg is hydrogen, lower alkyl, benzyl, benzhydryl.

I? -CH-O-C-R, Λ I 18 ,*X7 s„ 0 121 H -C-C-O-R I -CH- (CH-OH) - , or -CBL-CH— CH2 I I 2 OH OH R^ is hydrogen, lower alkyl, 'cycloalkyl, or phenyl.

R^j is hydrogen, lower alkyl, lower alkoxy, or phenyl or SX7 and Rlg taken together are -2)3-, -CH-CH-,. or .

Rjl and Rjj are independently selected from hydrogen and lower alkyl.

Rg3 is lower alkyl. -ΙΟIn accordance vith the invention, there is provided a compound of the formula (Π) o o R II ϋ 1 R--C-NH-CH-C-CH--N - CH-C-OH 2· I 2 *3 wherein: R is hydrogen, Prot, lower alkyl, cycloalkyl, I-Prot , -(CH2)3-3-Prot, -(CH2)4~R-Prot, -(CH2)2-0-Prot, -(CHj)j-O-Prot, -(CHj «-O-Prot , -(CH2)2-S-Prot, - (CHj) 3-S-Prot, or -(CHj)g-S-Prot; Rj is hydrogen, lower alkyl, halo substituted lower alkyl, f -(CHp^^-O-Frot, -(^Jr^-O-Prot . -(CHp—Tgj .

O-Prot A .« -(CH2)r-S-P.rot ·, “(CH2)r-S-lower alkyl.

I Prot NH Ι H iCH2,r~°Prot' -(Csp^-Prot, - , ^NH-Prot Ο II or - (CHg)r-C-NHg provided that Rg is hydrogen only when R is other than hydrogen; Prot is an easily removable protecting group; Rg is Rg is hydrogen, lower alkyl. halo substituted lower alkyl.

- (CHg) ^-cycloalkyl, -(αφΓ rQOH OH - 12 -1.ch2}, -lCH2)r-OH, , -(CH2)r-NH2, -(CH2)r-SH, -(CH2> S-lower alkyl, -(CK2)r-NH-C XNH2 or b -{ρΗ2)χ-ί:-ΝΗ2 « I Rgg is hydrogen, lower alkyl of 1 to 4 carbons, lower alkoxy of 1 to 4 carbons, lower alkylthio of 1 to 4 carbons, chloro, bromo, fluoro, trifluoromethyl, or hydroxy; m is zero, one, two, three, or four; p is one, two or three provided that p is more than one only if Rgg is hydrogen, methyl, methoxy, chloro, or fluoro; and z is an integer from 1 to 4 · The term lower alkyl used In defining various symbols refers to straight or branched chain radicals having up to seven carbons. The preferred lower alkyl groups are up to four carbons with methyl and ethyl most preferred, similarly the terms lower alkoxy and lower alkylthio refer to such lower alkyl groups attached to an oxygen or sulfur.

The term cycloalkyl refers to saturated rings of 3 to 7 carbon atoms with cyclopentyl and cyclohexyl being most preferred.

The term halogen refers to chloro, bromo and fluoro.

The term halo substituted lower alkyl refers to such lower alkyl groups described above in which one or more hydrogens have been replaced by chloro, bromo or fluoro groups such as trifluoromethyl, which is preferred, pentafluoroethyl, 2,2,2-trichloroethyl, chloromethyl, bromomethyl, etc. and The symbols represent that the alkylene bridge is attached to an available carbon atom. - 14 The compounds of formula I may be prepared by coupling a compound of the Invention with the amino or imino acid ester of the formula (ΠΙ) HX in the presence of a coupling agent such as dicyclohexylcarbodiimide wherein in the definition of X is an easily removable protecting group.

Removal of the Rfi protecting group yields the products of formula X wherein Rfi is hydrogen.

A compound of the invention can be prepared by reacting an amlnoketone of formula (IV) *3 vith a haloacetic acid ester of the formula (V) fl o I* 8 halo-CH — C-O-Prot (M wherein Prot is an easily removable ester protecting group such as t-butyl to yield the ester - 15 (VI) R I -ΝΗ Ο ο Ρ · -C-NH-CH-C-CH2 CH-C-0-Prot (U Removal of the ester protecting group gives a compound of the invention.

A compound of the formula (IV) can be prepared by converting the carbozyalkylamine of the formula (VII) R I HO-C-CH2-N-R40 P o wherein is a protecting group such as benzyloxy-0 carbonyl, to its acid chloride and then reacting with an oxazolone of foreula (VIII) to yield 15 (Π) O OR II I I R2-C-NH-CH-C-CH2-H-R40 *3 -)6Removal of the R4Q protecting group such as by hydrogenation yields the reactant of formula (IV).

The aminoketone of formula (IV) wherein R Is other than hydrogen can also be prepared by reacting the ketone of formula (X) O O I. I R--C-NH-CH-C-CH_-halo I *3 wherein halo is Cl or Br with a substituted amine of the formula (XI) R-NHj Compounds of formula (X) and their preparation are described and claimed in our Patent Application No. ( ).

In the above reactions if any or all of R, Rj , Rj and R^ are -(αφ^-^-on (CH.

OB OB - (CH2)r-NH2. - (CH2) qj-J f - (cap r-SH, H -2)x-oh. pr !~(CH2)r-NH-C^ NH ™2 - J7 then the hydroxyl, amino, imidazolyl, mercaptan or guanidinyl function should be protected during the reaction. Suitable protecting groups include benzyloxycarbonyl,. t-butoxycarbonyl, benzyl, benzhydryl, trityl, etc·, and nitro in the case of guanidinyl· The protecting group ls removed by hydrogenation, treatment with acid, or other known methods following completion of the reaction.

Preferred compounds of this invention vith respect to υ the peptide part of the structure are those.wherein: R is hydrogen, straight or branched chain lower alkyl of 1 to 4 carbons, or phenyl· Rg is hydrogen, straight or branched chain lower alkyl of 1 to 4 carbons, -CFg, -(CHgl^-NHg wherein r is an integer from 1 to 4, -ch2-© OR OH ' ““2 ir ι a e .MB - (CHg) 2-S-CH3, - (.CHg) 3NHC , -CHg-OH, XNHg O O II h -CHg-C-NHg, or -(CHgig-C-NHg provided that Rg is hydrogen only if R is other than hydrogen.

Most preferred compounds of this invention vith respect to the peptide part of the structure are those wherein: R is hydrogen or methyl· Rg is hydrogen, methyl, or -(CHg)gNHg, especially methyl, provided that Rg is hydrogen only if R is other than hydrogen· - 18 Preferred compounds of this invention with respect to the keto portion of the structure are those wherein; is wherein m is zero, one, or two and R^ is hydrogen, methyl, methoxy, methylthio, cl, Br, F, or hydroxy, especially phenyl.

Rj is straight or branched chain lower alkyl of 1 to 4 carbons, wherein m is' zero, .one,' or two, Rj is hydrogen «methyl, methoxy, methylthio, CX, Br, F, or hydroxy, and r is an integer from 1 to 4, especially benzyl.

An asymmetric center is present in the keto portion of the compounds of the invention when Rj is other than hydrogen. Thus, the compounds can exist in diastereoisomeric forms or in mixtures thereof.

The above described processes can utilize racemates, enantiomers or dlastereomers as starting materials. * When diastereomeric products are prepared, they can be separated by conventional chromatographic or fractional crystallization methods.

The compounds of formula X, and the pharma25 ceutically acceptable salts thereof, are hypotensive agents.

I - 19 The compounds of formula I wherein X is -NH-CH-COOR also possess enkephalinase I 6 *5 inhibition activity and are useful as analgesic agents.

Conpounds of formula (I), as veil as pharmaceutical compositions containing them and additional processes for their preparation, are further described and claimed in parent Patent Application No. 1655/83.

The following examples are illustrative of the preparation of compounds of the Invention, as well as their use in the preparation of compounds of formula (I). Temperatures are given in degrees centigrade. LH-20 refers to a Sephadex chromatography gel commercially available from Pharmacia Fine Chemicals. - 20 Example 1 ' N- [N- (3- (Benzoylamino) -2-oxo-4-phenylbutyll -H-wethylglycyl] -H-cyclohexylglyclne, monohydrochlor ide a] (3- (BenzoyAamlno) ^2-oxo-4-phenylbutyl]mcthylcarbamic acid, phenylmethyl ester N-methyl-N-'f (phenylmethoxy) carbonyl]glycine (2.23 g., 10 mmole) is dissolved in 30 ml. of tetrahydrofuran and cooled in an ice-bath. Oxalyl chloride (lml.r 11.5 mmole) is added followed by 2 drops of dimethylformamide. After stirring for 30 minutes in* the ice-bath, the mixture is then stirred at room temperature .for an hour. To this 0.25 ml. of oxalyl chloride is added. The mixture is evaporated, redissolved in 15 ml. of tetrahydrofuran, and stirred in an ice bath. A solution of 2-phenyl-4-(phenylmethyl)-5 (4H)-oxazolone (3.1 g., 12.4 mmole) dissolved in 15 ml. of tetrahydrofuran is added to the above solution stirring in the ice-bath. Triethylamine (1.4 ml., 10 mmole) is added and the solution is stirred at room temperature overnight. The precipitated triethylamine hydrochloride salt is* filtered off. Tetrahydrofuran is removed from the residue and it is then redissolved in pyridine (5 ml.) and p-dimethylamino pyridine (20 mg.) is added. After stirring at room temperature for 3 hours, acetic acid (5 ml.) is added and the.reaction mixture is Kept at 105* for 30 minutes. The reaction mixture is-then evaporated, the residue is dissolved in ethyl acetate, and washed with aqueous sodium bicarbonate and water. After trituration with ethyl acetate/ hexane, 2.2 g. of homogeneous [3-(benzoylamino)2-oxo-4-phenylbutyl]methylcarbamic acid, phenylmethyl ester is obtained; m.p, 140-141·, - 21 b) C ± 1-N- (3- (Methylamino) -2-oxo-1- (phenylmethyl) propy l]benzamide j hydrochloride (3- (Benzoylamino)-2-oxo-4-phenylbutyl]methylcarbamic acid, phenylmethyl ester (0.5 g.) is dissolved in ethanol (50 ml.) containing IN hydrochloric acid (2 ml.)· Palladium carbon catalyst (10%, 100 mg.) is added and hydrogenation is continued overnight. The reaction .mixture is then filtered, evaporated, dissolved in water, and lyophilized to 300 mg. of (±)-N-(3-(methylamino) -2-oxo-l- (phenylmethyl) propyl] benzamide, hydrochloride as a homogeneous white powder. c) (t)-N-(3-(Benzoylamino)-2-oxo-4-phenylbutyl]-Nmethylglycine,1,1-dimethylethyl ester To a solution of (±,-N-[3- (methylamino)-2-. oxo-1-(pheny lmethyl)propyl]benzamide (5.0 g., mmole) , prepared as set forth in (b) above, in dimethylformamide (20 ml.) is added bromoacetic acid, 1,1-dime thy lethyl ester (13.8 g., 3.15 ml., 19.5 mmole) and diisopropylethyIamine (2.5 g., 3.4 ml·, 19.5 mmole)· After stirring overnight at room temperature, the.reaction mixture is poured into water (100 ml.) and extracted with ethyl acetate (3x). The combined ethyl acetate extracts are washed with saturated sodium bicarbonate (twice), 10% potassium bisulfate (twice), and water * (twice), dried (Na^SO^), and concentrated into a yellow oil, .which becomes a dried up foam upon drying in high vacuum, to give 5.4 g. of (i) -N- (3- (benzoylamino) -2-oxo-4 -phenylbutyl) N-me thy Iglycine, 1,1-dimethy lethyl ester. - 22 d) _(i)-N-(3- (Benzoylamino)-2-oxo-4-phcnylbutyl]N-methylglycine, monohydrochloride The ester produdt from part (c) (4.51 g., mmole) is treated with 2N hydrochloric acid/ acetic acid (20 ml.)· After stirring for 2.5 hours at room temperature, the reaction mixture is concentrated under reduced pressure and the oily residue is tritOrated with ether to give 3.3 g. of (±) -N-(3- (benzoylamino) -2-oxo-4-pheny Ibutyl) 10 N-methyIglycine, monohydrochloride as an off-white solid. e) N-Cyclohexylglycine, Ι,Χ-dimethylethyl ester Cyclohexylamine (70.35 ml.) and sodium bicarbonate (x2.9 g.) are suspended with stirring in 200 ml. of absolute ethanol while stirring in an ice-bath. To this is' added bromoacetic acid, 1,1-dimethylethyl ester (20.78 ml.) dropwise· The ice-bath is removed. After 24 hours at room temperature, the reaction mixture is concentrated to dryness, taken into chloroform and washed with water. The crude product (42 g.) is chromatographed on silica gel eluting with ethyl acetate: hexane (2:1) to give 27.4 g. of N-cyclohexylglycine, 1,1-dimethylethyl ester.

(W-13 (Benzoylamino) -2—oxo-4-phenylbutyl) -Nmethylglycyl] -N-cyclohexylglycine, 1,1-dimcthylethyl ester To a solution of (i)~N-( 3-(benzoylamino) -2oxo-4,-phenyIbutylJ -N-methylglycine, hydrochloride (1.0 g., 2.6 mmole) in distilled tetrahydrofuran (50 ml.) is added* N-cyclohexylglycine, 1,1-dimethylethyl ester (0.55 g., 2.6 mmole), prepared as set forth in (e) above, hydroxybenzotriazole hydrate (0.39 g., 2.6 mmole) ,arid dicyclohexyl35 carbodiimide (0.55 g., 2.6 mmole). The reaction mixture Is stirred overnight, the precipitated - 23 dicyclohexylurea is filtered off, and the filtrate is concentrated· The residue is dissolved in ethyl acetate (50 ml.) and washed with saturated sodium bicarbonate (twice), 10% potassium bisulfate (twice), and water (twice), dried (Na^SO^) and concentrated Into an oily residue (1-5 g-). Flash chromatography (100 g·, Merck silica gel 60) gives 0.49 g. of N-[N-[3-(benzoylamino)-2-oxo'-4-phenylbutyl) “N-methylglycyl) -N-cyclohexylglycine ,1,1dimethylethyl ester as a foam. a) N-[N-(3- (Benzoylamino) -2-oxo-4-phenylbutyl)N-methylglycyl 1 -N-cyclohexylglycine, monohydrochloride The ester product from part (f) (0.48 g., 0.87 mmole) is treated with 2N hydrochloric acid/acetic acid (10 ml.K After stirring for 2 hours at room temperature, the reaction mixture is concentrated under reduced pressure and the oily residue is triturated with ether overnight to give 0.32 g. of N- (N- ( 3- (benzoylamino) -2-oxo-4-phenylbutyl] -Nmethylglycyl]-N-cyclohexylglycine, monohydrochloride as an off-white solid; m.p. 131-145®.

Rg 0.36 (silica gel, n-butanol/acetic acid/water; 4:1:1).

Anal, calc'd. for C28835N3°5 * Hcl ’ ®·7 H2°: C, 61.95; H, 6.95; N, 7.74; Cl, 6.53 Found: C, 61.95; H, 6.74; N, 7.71; Cl, 6.23. - 24 • Example 2 (S)-7-(ί [ (i)-3-(Benzoylamino) -2-oxo-4-phcnylbutyl?methylamino) acetyl 1 -1,4-di thia-7-azaspiro(4.4)nonane-8-carboxyllc acid, methyl ester TO a solution of (±)-N-[3-(benzoylamino)-2oxo’-4-phenylbutyl] -N-me thy Iglyclne, monohydrochlorlde (1.0 g.-, 2.5 mmole), prepared as set. forth In Example 1(d), ln distilled tetrahydrofuran (50 ml.) Is added (S) -1,4-dithia-7-azaspiro(4.4]nonane-8« carboxylic acid, methyl ester, monohydrochloride (0.66 g., 2.5 mmole), dicyclohexylcarbodiimide (0.54 g., 2.5 mmole), hydroxybenzotriazole hydrate I · (0.39 g., 2.5 mmole) and diisopropylethylamine (0.9 ml., 5· mmole). The reaction mixture is stirred overnight, the precipitated dicyclohexylurea is filtered off, and the filtrate is concentrated.

The residue is dissolved In ethyl acetate (100 ml.) and washed with saturated sodium bicarbonate (twice) and water (twice), dried (NagSOg), and concentrated into a yellow oily residue (1.3 g.). Flash chromatography- (Merck silica gel, 25* ethyl acetate/methylene chloride, 1* methanol/methylene chloride) affords 0.53 g. of (5)-7-((((2)-3(benzoylamino) -2-oxo-4-phonylbutyl]methylaaino]25 acetyl]-1,4-dithia-7-azaspiro (4.4] nonane-8carboxy lie acid, methyl ester as a white foam; m.p. 60 τ 62*. Rg 0.52' (silica gel, 5* methanol/ methylene chloride)· Axial, calc’d. for c2aH33N3°5S2 * °*33 H20i - 25 C, 59.87; Η, 6.04; N, 7.48; S, 11.42 Found: C, 59.87; H, 5.94; M, 7.56; S, 11.36.

Example 3 (S)-7- (11 (*) 3- (Benzoylamino) -2-oxo-4-phenylbutyl) 5 methy lamino] acetyl]-1,4-dithia-7-azaspiro( 4.4] nonane8-carboxyllc acid, methyl ester, monohydrochloride The methyl ester product from Example 2 (0.26 g., 0.46 mmole) is treated with 2N hydrochloric acid/acetic acid until homogeneous (2 minutes), concentrated under reduced pressure, and the oily residue is triturated with ether (twice) to give 0.26 g. of (5)-7-((((1)-3(benzoylamino) -2-oxo-4-phenylbutyl]methylamino] acetyl]-l,4-dithia-7-azaspiro(4.4] nonane-815 carboxylic acid, methyl ester, monohydrochloride as a white solid; m.p. 79-85*. Rf 0.53 (silica gel, 51 methanol/methylene chloride).

Anal, calc’d. for C28H33N3°5S2 * HC3 * ®·56 H^O: C, 55.84; H, 5.88; R, 6.98; S, 10.64; Cl,5.88 Founds C, 55.84; H, 5.95; N, 6.78; S, 10.43; Cl, 5.66. Example 4 (4S)-1-(Ν-Γ3-(Benzoylamino) -2-oxo-4-phenylbutyl]-NmethyIglycyl]-4-(4-fluorophenoxy)-L-;prollne, methyl ester, monohydrochloride a) (4S)-4-(fluorophenoxy)-L-prollne, methyl ester,' monohydrochloride TO a suspension of (4S)-4- (fluorophenoxy)L-proline (2.5 ‘g., XI mmole) in methanol at -3.0* under an argon atmosphere is* added thionyl chloride' (8.09 ml., 11 mmole). The reaction mixture · _______ - 26 is stirred at -20® for 2 hours, then at room temperature for 16 hours· Solvent Is removed at reduced pressure and the residue is redissolved in methylene chloride (150 ml.) and washed with* IN sodium carbonate (twice) and water (twice).

After drying (MgSOg) , excess hydrochloric acid/ methanol is added and solvent is removed at reduced pressure. Addition of ether gives a light brown solid (2.6 g·). Recrystallization from methanol/ ether gives 1.49 g. of (45) -4.- (fluorophenoxy) -Lproline, methyl ester, monohydrochloride as & light brown solid'; m.p. 147-148®; (α]θ “ +6.96® (c w 1.55, methanol). b) (4S)-l~-(N-[3- (Benzoylamino) -2-oxo-4-phenylbutyl) 15 N-methylglycyl] -4- (4-f luorophenoxy) -L-proline, methyl ester TP & solution of (±)-1(-[3-(benzoylamino)-2oxo-4-pheny Ibutyl] -N-methylglycine, monohydrochloride (1.17 g., 3 mmole), prepared as set forth in Example 1(d), in distilled tetrahydrofuran (20 ml.) is added (4S)-4-(fluorophenoxy)-L-proline, methyl ester, monohydrochloride (0.82 g., 3 mmole), hydroxybenzotriazole hydrate (0.46 g., 3 mmole) and dicyclohexylcarbodiimide (0.62 g., 3 mmole).

The reaction mixture is stirred overnight, the' precipitated dicyclohexylurea is filtered off, and the 'filtrate is concentrated. The residue is • · · dissolved in ethyl acetate (50 ml.) and washed with saturated sodium bicarbonate (twice) and water (twice) , dried (Na2SOg) ,* and concentrated into an - 27oily residue (l.l g,). Flash chromatography (200 g., Merck silica gel 60; 3t methanol/chloroforra) gives 0.15 g. ol (4S)-l-(M-(3-(bensoylamino)-2oxo-4-phenylbutylJ-H-methylglycylJ-4-(4-fluoro5 phenoxy)-L-proline, methyl ester as a foam, c) 14 S -1- (8- (3- (Bensoylamino) -2-oxo-4 -phenylbutyl] -W-methylqlycyl) -4-(4-fluorophenoxy) -2prollne, methyl ester, monohydrochloride The methyl ester product from part (b) (0.15 g., 0.26 mmole) is treated with 28 hydrochloric acid/acetic acid until homogeneous (2 minutes), concentrated under reduced pressure, and the oily residue is triturated with ether (twice) to afford 0.14 g. of (45)-1-(8-(315 (benzoylamino)-2-oxo-4-phenylbutyl]-K-raethylglycyl]-4-(.4-fluorophenoxy)-L-proline, methyl ester, monohydrochloride as an off-white solid; m.p. 105-125·. Rg 0.27 (silica gel, 54 methanol/ chloroform).

Anal, calc'd. for CjgRjgVOg - BCl C, 62.79; H, 5.76; 8, 6.86; F, 3.10; Cl,5.79 Found: C, 62.78; H, 5.73; N, 6.87; F, 2.83; Cl,5.33. - 28 •Example 5 (4S) -1-TNt (S)-3- (Benzoylamino) -2-oxo-4-phcnylbutyl]L-aianyl]-4-<4-fluorophenoxyj-L-prollne, monohydrochloride a) (S) -N- [3- (Benzoylamino) -2-oxo-4-phenylbutyl )L-alanine, 1,1-dlmethylethyl ester To a stirring solution of (S)-N-(3-chloro2-oxo-1-(phenylmethyllpropyl]benzamide (10.0 g., 33.1 mmole) In dimethylformamide (80 ml.) is added L-alanine, 1,1-dlmethylethyl ester, hydrochloride (6.0 g., 33.1 mmole), sodium bicarbonate e (6.1 g·, 72 mmole) and sodium iodide (4.9 g·, 33.1 mmole)· The resulting solution is stirred overnight at room temperature, poured into ether and washed with water (twice) and 10% sodium bicarbonate. The ether solution is extracted with IN hydrochloric acid (3x), the combined extracts are made basic by the addition of solid sodium* bicarbonate and extracted with ethyl acetate (4x). 2q The organic extracts are combined, dried (HgSOg) and concentrated to give 8.9 g. of pale yellow solid, λ portion of this material is recrystallised from ethyl acetate to give (S)-N-(3(benzoylamino) -2-oxo-4-phehylbutylJ -L-alanine, 1,1-dimethylethyl ester as a white solid; m.p. 106.5 - 110·. - 29 b) (S)-N-[3- (Borizoylamino)-2-oxo-4-phenylbutyl)L-alanine, monohydrochlonide A solution of the ester product from part a (a) (2.95 g., 5.4 mmole) in 1.4 N hydrochloric acid in acetic acid* (39 ml.) ia stirred at room temperature for 2 hours. The resulting white precipitate Is collected, rinsed with ether and dried to give 2.27 g. of (S)-N-£3-(benzoylamino)-2oxo-4-phenylbutyl]-L-a.lanine, monohydrochlorlde; m.p. 208-209* (dec.); [β]^ = -71* (c » 0.38% in methanol). Rg 0.51 (silica gel; chloroform/ methanol/acetic Acid; 4:1:1).’ Anal, calc'd. for C20H22M2°4 ’ HCIS C, 61.64; H, 5.93;. N, 7.17; Cl, 9.07 Founds C, 61.33; H, 5.97; K, 7.17; Cl, 8.79. cj_(S) -Μ- [N- (Benzoylamino) -2-oxo-4-phdhy Ibutyl) N- [ (phenylmethoxy) carbonyl j -L-alanine Triethylamine (2.1 ml., 15 mmole)' is added to a mixture of . (S)-N-(.3- (benzoylamino)2-oxo-4-pheny Ibutyl ] -L-alanine , monohydrochlorlde (2.0 g., 5.1 mmole), benzyl chloroformate (730 μ1·, .1 mmole) , water* (7 ml .J and dioxane* (7 ml.) at 25· · The resulting mixture is stirred at 25· for 3 hours, after which it* is* poured into 5% aqueous, sodium bicarbonate solution and ' washed with ether. The aqueous layer is' acidified (HClland.extracted, into ethyl acetate (3x). The extract is* dried* (MgSO*) and concentrated to give a colorless oil*. ' Trituration with ether * produces a white granular solid* · (150 mg.’) 'which - 30 is collected and discarded. The mother liquor Is concentrated in vacuo to give 1.7.5 g. of (S)-N(N- (benzoylamino) -2-oxo-4-pheny Ibutyl] -ΜΙ (phenylmethoxy) carbonyl]-L-alanine as a white glass. d) (4S)-l-(N-( (5)-3-(Benzoylamino)-2-oxo-4phenyIbutyl]-N- ((phenylmethoxy)carbonyl] -Lalanyl] -4- (4-fluorophenoxy) -L-proline, phenylmethyl ester A mixture of (S)-N-(N-(benzoylamino)-2oxo-4-pheny Ibutyl] -N- ('(phenylmethoxy) carbonyl] -Lalanine (300 mg., 0.62 mmole), (4S)-4-(4-fluorophenoxy)-L-proline, phenylmethyl ester, pfoluenesulfonic acid salt (300 mg., 0.62 mmole), triethylamine (90 pi., 0.62 mmole), dicyclohexylcarbodiimide (130 mg·, 0.62 mmole), and hydroxybenzotriazole hydrate (90 mg., 0.62 mmole) in tetrahydrofuran (7 ml.) is stirred at 25* for 20 hours. The mixture is then filtered and diluted with ethyl acetate. The resulting solution is washed sequentially with IN hydrochloric acid and 10% aqueous sodium bicarbonate solution, dried (MgSO^) , filtered, and concentrated to give 500 mg. of (4S)-l-(N-((S)-3-(benzoylamino)-2-oxo-425 pheny Ibutyl] -N- ((phenylmethoxy) carbonyl] -Lalanyl] -4- (4-fluorophenoxy) -L-proline, phenylmethyl ester as a pale yellow oil. - 31 e) (4S)-1-(8-((5)-3-(Benzoylamino)-2-oxo-4phcnylbutyl)-L-alanyl)-4-(4-fluorophenoxy) -Lprollne, monohydrochloride A mixture of the ester product from part(d) (500 mg., 0.6 mmole), palladium on carbon catalyst (10%, 100 mg·), absolute ethanol (15 ml.), and 1.0 N aqueous hydrochloric acid (800 vl., 0.8 mmole) is hydrogenated at 1 atmosphere and 25° for 17 hours, after which it is filtered and concentrated.

The residue is chromatographed on HP-20 a linear gradient from (9:1, 0.01N aqueous hydrochloric acidsmethanol) tp (1:1, 0.01N aqueous hydrochloric acid:methanol]. Fractions containing the desired product (TLC) are combined and concentrated. The X5 residue is dissolved in a minimum amount of methanol. Ether is added, resulting in a white precipitate which is collected and dried ln vacuo to give 200 mg. of (4S)-1-[N-[(S)-3-(benzoylamino)2-oxo-4-pheny lbutyl] -L-alanyl]-4- (4-f luorophenoxy) 20 L-proline, monohydrochloride; m.p. 152-153° (dec·); (a] J5 “ -50° (c 0.5, methanol).

Rg 0.75 (silica gel, chloroform/methanol/acetic acid, 4:1:1).

Anal, calc'd. for CjjHjjFNjOg - HCl * 1.5 HjO: C, 59.57; H, 5.80; N, 6.72; Cl*, 5.67 Found: C, 59.68; H, 5.56; N, 6.67; Cl, 5.99. - 32 Example 6 - ~ (1 (S),4R]-1-[N-[3-(Benzoylamino)-2-ΟΧΟ-4-pheny Ibuty 1)L-alanyl]-4-phenyl-L-prollne, monohydrochloride a) _(S)-N-[N-(Benzoylamino)-2-oxo-4-phenyIbuty1j-N5 ((phenylmethoxy).carbonyl)-L-alanlne, succinimido ester A mixture of (S)-N-[N-(benzoylamino)-2-oxo4-phenylbutyl)-N-((phenylmethoxy)carbonyl]-Lalanine .(800 mg·, 1.6 mmole), prepared as set forth in Example 5 (c), dicyclohexylcarbodiimide (340 mg., 1.6 mmole), and N-hydroxysuccinimide (190 mg., 1.6 mmole) in tetrahydrofuran (5 ml.) is stirred at 25? for 18 hours. After this time it is filtered and concentrated'to give 950 mg. of (S)-N-(N-(benzoylamino)-2~oxo-4-phenylbutyl)15 (phenylmethoxy)carbonyl]-L-alanine, succinimido ester. b) (1(8).4R]-l-(N-[3-(Benzoylamino]-2-oxo-4phenylbutyl) -N-( (phenylmethoxy) carbonyl] -Lalanyl]-4-phenyl-L-proline To a solution of (S)-N-(N-(benzoylamino)-2oxo-4-phenylbutyl] -N- ((phenylmethoxy) carbonyl] -Lalanine, succinimido ester (950 mg., 1.6 mmole) in dimethylformamide (5 ml.) is added (4R)-4phcnyl-L-proline, hydrochloride (375 mg., 1.7 mmole) and triethylamine (40 yl·, 3.2 mmole). The resulting mixture is .stirred at 25s for 24 hours, after which it is poured into excess.IN hydrochloric acid and extracted with ethyl acetate (3x) · The extracts are combined, dried (MgSO*) , filtered, and concentrated to give 1.1 g. of - 33 [1(S),4R] -Ι-(Ν-[3- (benzoylamino) -2-oxo-4-phenylbutyl] -N- ((phenylmethoxy) carbonyl] -L-alonyl] -4phenyl-L-proline. c) [1(5),4Rj-l-[N-[3-(Benzoylamino)-2-oxo-45 phenylbutyl] -L-alanyl]-4-phenyl-L-proline, mono- . hydrochloride The product from part (b) (1.0 g., 1.5 mmole), ethanol (20 ml.)^ water (5 ml·), 1.0 N hydrochloric acid (1.5 ml·, 1.5 mmole), and palladium on carbon catalyst (10%, 100 mg.) is hydrogenated at one atmosphere and 25s for 18 hours, after which it is filtered and concentrated. The residue is chromatographed on HP-20 -using a linear gradient (0.01 N aqueous hydrochloric acid imethanol, 40:60 to 10:90]· Fractions containing the desired product (TLC) are combined and concentrated. The residue is dissolved in minimum amount of methanol. Ether is added and the resulting white a precipitate is collected and dried to give 300 mg. of* (1 (S) ,4R]-1-(N-(3- (benzoylamino) -2-oxo-4-phenylbutyl] -L-alanyl}-4-phenyl-L-proline f monohydrochloride; m.p. 160-162* (dec.); (nJ** “ -57* (c 1.5., methanol). Rg 0.8 (silica gel; chloroform/methanol/acetic acid; 4:1:1).

Anal, calc’d.* for £3^33 ' I·35 HgO: C, 63.27; H, 6.29; N, 7.14; Cl, 6.02* Found: C, 63.27; H, 6.17; N, 7.19; Cl, 5.97. - 34 Example 7./ (l(S) ,4S]-1- [N-[3- (Benzoylamino) -2-oxo-4-phenylbutyl] -L-alanyl]-4-phenyl-L-proline, monohydrochloride Following the procedure of Example 6 but employing (45)-4-phenyl-L-prolinej hydrochloride in part (b), one obtains (1 (S),4S]-1-[N-(3-(benzoyl amino) -2-oxo-4-pheny Ibutyl) -L-alanyl-4-phenyl-Lprollne, monohydrochloride; m.p. 138-143°; (σΙρ -61* (c w 0.3% in methanol). Rg 0.84 (silica gel, chloroform/methanol/acetic acid, 4x1x1).

Anal, calc'd. for C31H33N3O5 ’ HCI * 2.13 HjO: C, .61.80; H, 6.35; N, 6.98; Cl, 5.88 Found: C, 61.80; H, 6.06; N, 7.05; Cl, 5.65. Example 8 (1 (S) , 4R] -I-(Ν- (3- (Benzoylamino) -2-oxo-4-phenylbutyl] -L-alanyl] -4-cyclohexyl-L-prollne, monohydrochloride Following the procedure of Example 6 but employing (4R)-4-cyclohexyl-L-prollne, hydrochloride in part (b) , one obtains (1(S),4R]-1[N-(3- (benz0ylaminb-2-oxo-4-pheny Ibutyl] -Lalanyl] -4-cyclohexyl-L-proline, monohydrochloride; m.p. 140-154° (dec.); [i)D “ -83° (c - 0.36% in methanol). Rg 0.84 (silica gel; chloroform/ methanol/acetic acid; 4:1x1). 5Anal. calc'd. for ^-33^39^3% * HCl * 0.79 H^O: C, 63.71; H, 7.17; N, 7.19; Cl, 6.06 Found: C, 63.71; H, 7.21; N, 7.05; Cl, 5.82.

Example 9 (1 (S),4S]-1-[N-(3- (Benzoylamino) -2-oxo-4-phenyl-butyll -L-alanyl] -4-cyclohexyl-L-proline, monohydrochloride Following the procedure of Example 6 but employing (45)-4-cyclohexyl-L-proline, hydrochloride in part (b), one obtains [1 (S) ,4S]-l-[N-(.3(benzoylamino) -2-oxo-4-pheny Ibutyl ] -L-alanyl)-4cyclohexyl-L-proline, monohydrochloride; m.p. 139-141· (dec.); [a)0w 80· (c “ 0.21 in methanol). Rg 0.83 (silica gel; chloroform/methanol/ acetic acid; 4:1:1)., Anal, calc'd. for ^33^39^3^5 * HCl ‘ 1-5( ^0: C, 62.28; H, 7.26; N, 7.03; Cl, 5.93 Found: C, 62.28: H, 7.01; N, 7.02;.'Cl, 6.16.

Example iu (S)1-7-[ (S)r2-{(3— (BenzOylamino)-2-oxo-4-phenylbutyl]aminol-l-oxopropyl) -1,4-dithia-7-azaspirp(4.4] nonane8-carboxylic acid, monohydrochloride Following the procedure of Example 6 . but employing (S)-l,4-dithia-7-azaspiro[4.4)nonane-8carboxylic acid, hydrochloride in part (b) for the e L-proline reactant, one obtains (S)-7-[(5)-2-((3(benzoy lamino) -2-oxo-4-phehy Ibutyl] amino] -1oxopropy 1 ] -1,4-d.lthia-7.-az aspiro (4.4) nonane- 8carboxyliti acid*, monohydrochloride; m.p. 170-172°; - 36 ι I le]J8 -26° (c - 1.4% In methanol). Rg 0.78 (silica gel; chloroform/methanol/acetic acid; 6:1:1).

Anal, calc'd. for C27H31N3°5S2 ’ HC1 ’ °-7™2O: C, 54.77; H, 5.71; N, 7.10; S, 10.83; Cl, 5.99 Found: C, 54.77; H, 5.70; N, 6.94; S, 10.82; Cl, 6.07.

Example 11 [ 1(5) ,5S]-1—[N-(3—(Benzoylamino)-2-oxo-4— pheny lbutyl) -L-alanyi] -4,5-dihydro-3-phenyl-lHpyrazole-5-carboxyllc acid, monohydrochloride Following the procedure of Example 5 but employing (S] -4,5-dihydro-3-phenyl-lH-pyrazole-515 carboxylic acid for the L-proline reactant in part (b), one obtains the above named compound.

Example 12^ (S) -2- (H- ( f 4-tetrahydro-3-isoquinoiinecarboxylic acid, monohydrochloride Following the procedure of Example 6 . but employing (S) -1,2,3,4-tetrahydro-3-isoguinolinecarboxylic acid, hydrochloride in part (b) in place of the proline reactant, one obtains (S)-2-(N-((S)25 3- (benzoylamino) -2.-oxo-4-phehy lbutyl] -L-alanyl] -1, 2,3,4-tetrahydro-3.-^isoquinblinecarboxylic acid, * monohydrochloride · 1— tM— t(5)-3γ(Benzoylamino)-2?-oxo-4-phenylbutyl]-Lalanyl]-2-(2-hydroxyphenyl)-4(R)-thiazolldinecar* a boxy11c acid, monohydrochlorlde Following the procedure of Example 6 but employing 2-((2-phenylmethoxy)phenyl]-4(R)-thiazolidinecarboxylic acid, hydrochloride in » part (b) in place of the proline reactant, one obtains after removal of the hydroxy protecting group l-(N-( (S)-3-(benzoylamino)-2.-oxo-4pheny Ibuty 1] -L-alanyl] -2- (2-hydroxyphenyl) 4 (R)-thiazolidinecarboxylic acid, monohydrochlorlde·

Claims (8)

1. CLAIMS λ compound of the formula Ο O R R. O ii ρ ι r ii R--C-NH-CH-C-CH--N - CH-C-OH ? , 2 R, wherein: R is hydrogen, Prot, lower alkyl, cycloalkyl, Η H - (CHj) 2 -H-Prot , - (CHj) j-N-Prot, -(CHjJj-O-Prot, -(CHj)j-O-Prot, -(CH 2 ) 4 -0-Prot , -(CH 2 ) 2 -S-Prot, -(CHjJj-S-Prot, or -(CHj) 4 -S-Protj - 39 Rj is hydrogen, lower alkyl, halo substituted lower alkyl, _ f ' (CH 2’F© -(CHjJj^^-O-Prot (CH.,) Prot , -(CH,) O-Prot (CH 2 , r^~^ ' -(CH 2 > r -S-P.rot ·, -(CH 2 ) r -S-lower alkyl. N I < Prot - CCH 2 ) r -0-Prot, - (CH 2 ) r -N-Prot, - (CH^-NH-CT ft . NH-Frot or - (CH 2 > r “C-NH 2 provided that Rj is hydrogen only when R is other than hydrogen; Prot is an easily removable protecting group; Rj is t Rg is hydrogen, lower alkyl. -«VsTjJ ' “‘«Pm-b j halo substituted lower a).kyl. -(CHj -cycloalkyl, a m -(¾ OH » OH -<·«2>£ , (CH 2 , r OR ’ I a , -(CHg, r -NHg, -(CHg) r -SH, -^ CH 2^ r “S-lower alkyl, -(CHg) r ~NH-C , or X NHg b -(CHg) r -C-NHg< f Rgg is hydrogen, lower alkyl of 1 to 4 carbons, lower alkoxy of 1 to 4 carbons, lower alkylthio of 1 to 4 carbons, chloro, bromo, fluoro, trifluoromethyl, or hydroxy; m is zero, one, two, three, or four; p is one, two or three provided that p is more than one only if Rgg is hydrogen, methyl, methoxy, chloro, or fluoro; and r is an integer from 1 to 4'·

2. A compound according to Claim 1 wherein R~ is Λ - 42 Rj iS m is zero, ore, or two; Rj 4 is hydrogen, methyl, methoxy, methylthio, chloro, .bromo, fluoro, or hydroxy; R is methyl; and Rj is hydrogen.

3. A compound according to Claim 2 wherein is phenyl and Rj is benzyl.

4. . A compound according to Claim 1 wherein: m is zero, one or two; Rj 4 is' hydrogen, methyl, methoxy,; methylthio', chloro, bromo, fluoro pr hydroxy;; R is an easily removable protecting 'group; and Rj is methyl.

5. . A compound according to Claim 4 wherein: »2 P hen y^/ Rj im' benzyl; and

6. A compound according to claim 1 as herein specifically disclosed.

7. A process for the preparation of a compound according to claim 1 which comprises reacting an aminoketone of formula 0 OR I I I C —NH-CH-C-CH,—NH- ♦ 2 I 2 (wherein R, Rj and haloacetic acid ester R^ are as defined in of formula claim 1) with a halo-CH-C-O-Prot (wherein R^ is as defined in claim 1; halo is Cl or Br; and Prot is an easily removable ester protecting group) to yield the ester of formula R R, Q K 2 —C-NH-CH-C-C^-NH-L-C-O-Prot followed by removal of the Prot group.

8. A process for the preparation of a compound according to claim 1 substantially as herein described.