Field of the Invention:

The present invention provides a process for the preparation of (2S)-N-((S)-l-((S)-4-methyl-1 -((R)-2-methyloxiran-2-yl)-1 -oxopentan-2-ylcarbamoyl)-2-phenylethyl)-2-((S)-2-(2-morpholinoacetamido)-4-phenylbutanamido)-4-methylpentanamide represented by the following structural formula-1.
6 ^
Formula-1 Background of the Invention:
(2S)-N-((S)-1 -((S)-4-methyl-1 -((R)-2-methyloxiran-2-yl)-1 -oxopentan-2-yl carbamoyl)-2-phenylethyl)-2-((S)-2-(2-morpholinoacetamido)-4-phenylbutanamido)-4-methylpentanamide, commonly known as Carfilzomib is an anti-cancer drug acting as a selective proteasome inhibitor which is indicated for the treatment of patients with multiple myeloma who have received at least two prior therapies including Bortezomib and an immunomodulatory agent. It is a tetrapeptide epoxyketone and an analog of Epoxomicin.
US7417042B2 has described Carfilzomib, its analogous compounds and also process for their preparation.

Brief description of the invention:

The first aspect of the present invention is to provide process for the preparation of (2S)-N-((S)-1 -((S)-4-methy 1-1 -((R)-2-methyloxiran-2-yl)-1 -oxopentan-2-ylcarbamoyl)-2-phenylethyl)-2-((S)-2-(2-morpholinoacetamido)-4-phenylbutanamido)-4-methylpentanamide
compound of formula-1.
The second aspect of the present invention is to provide novel intermediate compounds which are useful in the preparation of compound of formula-

1. The third aspect of the present invention is to provide a process for the preparation of (2S)-N-((S)-1 -((S)-4-methyl-1 -((R)-2-methyloxiran-2-yl)-1 -oxopentan-2-ylcarbamoyl)-2-phenylethyl)-2-((S)-2-(2-morpholinoacetamido)-4-phenylbutanamido)-4-methylpentanamide
compound of formula-1.
Detailed description of the Invention:
The term "suitable solvent" used in the present invention refers to "hydrocarbon solvents" such as n-pentane, n-hexane, n-heptane, cyclohexane, pet ether, benzene, toluene, xylene and the like; "ether solvents" such as dimethyl ether, diethyl ether, diisopropyl ether, methyl tert-butyl ether, 1,2-dimethoxyethane, tetrahydrofuran, 1,4-dioxane and the like; "ester solvents" such as methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, tert-butyl acetate and the like; "polar-aprotic solvents" such as dimethylacetamide, dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone (NMP) and the like; "chloro solvents" such as dichloromethane, dichloroethane, chloroform, carbon tetrachloride and the like; "ketone solvents" such as acetone, methyl ethyl ketone, methyl isobutyl ketone and the like; "nitrile solvents" such as acetonitrile, propionitrile, isobutyronitrile and the like; "alcohol solvents" such as methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, t-butanbl, ethane-1,2-diol, propane-1,2-diol and the like; "polar solvents" such as water; formic acid, acetic acid or mixture of any of the aforementioned solvents.

The term "suitable base" used in the present invention refers to "inorganic bases" selected from "alkali metal carbonates" such as sodium carbonate, potassium carbonate, lithium carbonate, cesium carbonate and the like; "alkali metal bicarbonates" such as sodium bicarbonate, potassium bicarbonate, lithium bicarbonate, cesium bicarbonate and the like; "alkali metal hydroxides" such as sodium hydroxide, potassium hydroxide, lithium hydroxide and the like; "alkali metal alkoxides" such as sodium methoxide, sodium ethoxide, potassium methoxide, potassium ethoxide, sodium tert.butoxide, potassium tertbutoxide, lithium tert.butoxide and the like; "alkali metal hydrides" such as sodium hydride, potassium hydride, lithium hydride and the like; "alkali metal amides" such as sodium amide, potassium amide, lithium amide and the like; alkali metal and alkali earth metal salts of acetic acid such as sodium acetate, potassium acetate, magnesium acetate, calcium acetate and the like; ammonia; "organic bases" like dimethylamine, diethylamine, diisopropyl mine, diisopropylethylamine, diisobutylamine, triethylamine, triisopropyl amine, tributylamine, tert.butyl amine, pyridine, 4-dimethylaminopyridine (DMAP), imidazole, N-methylimidazole, l,8-diazabicyclo[5.4.0]undec-7-ene (DBU), l,5-diazabicyclo[4.3.0]non-5-ene (DBN), N-methylmorpholine (NMM), l,4-diazabicyclo[2.2.2]octane (DABCO), 2,6-lutidine and the like; "organolithium bases" such as methyl lithium, n-butyl lithium, lithium diisopropylamide (LDA) and the like; "organosilicon bases" such as lithium hexamethyldisilazide (LiHMDS), sodium hexamethyldisilazide (NaHMDS), potassium hexamethyldisilazide (KHMDS) and the like or their mixtures.

The term "suitable acid" used in the present invention refers to hydrochloric acid, hydrobromic acid, nitric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, trifluoroacetic acid, alkyl/aryl sulfonic acids such as methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, malic acid, maleic acid, fumaric acid, tartaric acid, mandelic acid, acetyl mandelic acid, oxalic acid, citric acid, succinic acid and the like.
The first aspect of the present invention provides a process for the preparation of (2S)-N-((S)-1 -((S)-4-methy 1-1 -((R)-2-methyloxiran-2-yl)-1 -oxopentan-2-ylcarbamoyl)-2-phenylethyl)-2-((S)-2-(2-morpholinoacetamido)-4-phenylbutanamido)-4-methylpentanamide
compound of formula-1, comprising of;
a) Reacting the (S)-2-((S)-4-methyl-2-((S)-2-(2-morpholinoacetamido)-4-phenyl
butanamido)pentanamido)-3-phenylpropanoic acid compound of formula-2


with compound of general formula Ri-OH in a suitable solvent in presence of a suitable coupling agent and/or a suitable base to provide compound of general formula-3,

b) optionally isolating the compound of general formula-3 as a solid,
c) reacting the compound of general fomula-3 with (S)-2-amino-4-methyl-l-((R)-2-methyloxiran-2-yl)pentan-l-one compound of formula-4 or its acid-addition salt
O
Y
Formula-4 in a suitable solvent optionally in presence of a suitable base to provide compound of formula-1.
Wherein, 'Ri' is selected from the following groups;

In step-a) the suitable coupling agent is selected from but not limited to U'-carbonyldiimidazole (CDI), N,N'-dicyclohexylcarbodiimide (DCC), N,N'-diisopropyl carbodiimide (DIC), 1 -ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC.HC1), l-[bis(dimethylamino)methylene]-lH-l,2,3-triazolo[4,5-b]pyridinium 3-oxid hexafluoro phosphate (HATU), 2-( 1 H-benzotriazol-1 -yl)-1,1,3,3 -tetramethy luronium hexafluoro phosphate (HBTU), lH-benzotriazolium l-[bis(dimethylamino)methylene]-5chloro-hexafluorophosphate( 1 -)3 -oxide (HCTU), 0-(benzotriazol-1 -yl)-N,N,N',N'-

tetramethyl uronium tetrafluoroborate (TBTU), alkyl/aryl haloformates selected from but not
limited to ethyl chloroformate, benzylchloroformate; diphenylphosphoroazidate (DPPA),
thionyl chloride, oxalyl chloride, phosphorous oxychloride, phosphorous pentachloride,
4-methyl-2-oxopentanoyl chloride (i-BuCOCOCl), (benzotriazol-1 -yloxy)
tris(dimethylamino)phosphonium hexafluorophosphate (BOP), benzotriazol-1 -yl-oxytripyrrolidinophosphonium hexafluorophosphate (PyBOP), methanesulfonyl chloride, p-toluenesulfonyl chloride and the like.
In step-a) & step-c) the suitable base is selected from organic bases, inorganic bases, organolithium bases and organosilicon bases or their mixtures; and the suitable solvent is selected from hydrocarbon solvents, ether solvents, ester solvents, polar-aprotic solvents, chloro solvents, ketone solvents, nitrile solvents, alcohol solvents, polar solvents or their mixtures.
A preferred embodiment of the present invention provides a process for preparation of (2S)-N-((S)-1 -((S)-4-methy 1-1 -((R)-2-methyloxiran-2-yl)-1 -oxopentan-2-ylcarbamoyl)-2-phenylethyl)-2-((S)-2-(2-morpholinoacetamido)-4-phenylbutanamido)-4-methylpentanamide
compound of formula-1, comprising of;
a) Reacting the (S)-2-((S)-4-methyl-2-((S)-2-(2-morpholinoacetamido)-4-phenyl
butanamido)pentanamido)-3-phenylpropanoic acid compound of formula-2 with
. N-hydroxysuccinimide in a suitable solvent in presence of a suitable coupling agent
and/or a suitable base to provide (S)-2,5-dioxopyrrolidin-l-yl 2-((S)-4-methyl-2-((S)-2-
(2-morpholinoacetamido)-4-phenylbutanamido)pentanamido)-3-phenyl propanoate
compound of formula-3 a,
■


b) optionally isolating the compound of formula-3a as solid,
c) reacting the compound of fomula-3a with (S)-2-amino-4-methyl-l-((R)-2-methyloxiran-2-yl)pentan-l-one compound of formula-4 or its acid-addition salt in a suitable solvent optionally in presence of a suitable base to provide compound of formula-1.
Wherein, the suitable coupling agent, the suitable base and the suitable solvent are same as defined in the first aspect of the present invention.
The S)-2-amino-4-methyl-l-((R)-2-methyloxiran-2-yl)pentan-l-one compound of formula-4 or its acid-addition salt and (S)-2-((S)-4-methyl-2-((S)-2-(2-morpholino acetamido)-4-phenylbutanamido)pentanamido)-3-phenylpropanoic acid compound of formula-2 utilized in the above aspect can be manufactured by any of the known processes or it can be synthesized by the process as illustrated in the present application!
The second aspect of the present invention provides novel intermediate compounds which are useful in the preparation of compound of formula-1. The said novel intermediate compounds are represented by the below mentioned structural formula


A preferred embodiment of the present invention provides (S)-2,5-dioxopyrrolidin-l-yl2-((S)-4-methyl-2-((S)-2-(2-morpholinoacetamido)-4-phenylbutanamido)pentanamido)-3-
phenyl propanoate compound of formula-3a, which is an useful intermediate in the synthesis
of compound of formula-1.

Another embodiment of the present invention provides solid state form of (S)-2,5-
dioxopyrrolidin-1-yl 2-((S)-4-methyl-2-((S)-2-(2-morpholinoacetamido)-4-phenyl
butanamido)pentanamido)-3-phenylpropanoate compound of formula-3a.
The third aspect of the present invention provides a process for the preparation of (2S)-N-((S)-1 -((S)-4-methyl-1 -((R)-2-methyloxiran-2-yl)-1 -oxopentan-2-ylcarbamoyl) -2-phenylethyl)-2-((S)-2-(2-morpholinoacetamido)-4-phenylbutanamido)-4-methylpentanamide
compound of formula-1, comprising of reacting the compound of general formula-3,

wherein, cRi' is as defined above;
with (S)-2-amino-4-methyl-1 -((R)-2-methyloxiran-2-yl)pentan-1 -one compound of i formula-4 or its salt in a suitable solvent optionally in presence of a suitable base to provide compound of formula-1.

Wherein, the suitable base and the suitable solvent are same as defined in step-c) of the first aspect of the present invention.
The (2S)-N-((S)-1 -((S)-4-methyl-1 -((R)-2-methyloxiran-2-yl)-1 -oxopentan-2-yl
carbamoyl)-2-phenylethyl)-2-((S)-2-(2-morpholinoacetamido)-4-phenylbutanamido)-4-methylpentanamide compound of formula-1 of the present invention is purified by flash chromatography under the following conditions;
Apparatus: Grace Reveleris X.2 Flash chromatography system equipped with variable wavelength UV-detector; Cartridge: Silica 120 grams 100A° lOum (Phenomenex silica); Wavelength: 210 nm; Mobile phase-A: n-hexane; Mobile phase-B: 1% water in isopropyl alcohol; Diluent: dichloromethane.
The compound of formula-1 is purified by preparative HPLC under the following conditions;
Apparatus: Hanbon Sci & Tech preparative HPLC system equipped with variable wavelength UV-detector; Column: dynamic axial compression column CI8 400 * 50 mm, 10 urn; Wavelength: 210 nm; Injection volume: 40 mL; Diluent: mobile phase A:B (40:60 v/v); Elution: Isocratic; Pump-A: water; Pump-B: acetonitrile; Mobile phase: Pump-A : pump-B (40:60 v/v).
The compound of formula-1 obtained by the process of the present invention was analyzed y HPLC under the following conditions;
Column: Purospher STAR-RP 18 endcapped, 150 x 4.6 mm, 3 urn; Wavelength: 210 nm; Injection volume: 10 |imL; Column temperature: 35°C; Diluent: Milli-Q-water:acetonitrile (1:1 v/v); Elution: gradient; Buffer: Weigh accurately about 1.36 gm of potassium dihydrogen phosphate and 3.0 grams of 1-octanesulfonic acid anhydrous in 1000 mL of milli-Q-water and adjust the pH to 3.0 with dilute ortho phosphoric acid and filter the solution through 0.22 urn Nylon membrane filter paper; Mobile phase-A: Buffer: acetonitrile (70:30 v/v); Mobile phase-B: Acetonitrile : buffer (70:30 v/v).

The present invention is schematically represented as follows. Scheme-1:

Wherein, 'Rf is same as defined in the specification.
The best mode of carrying out the present invention is illustrated by the below provided examples. These examples are provided as illustration only and hence should not be construed as limitation to the scope of the invention.

Examples:
Example-1: Preparation of (S)-methyl 2-amino-3-phenylpropanoate hydrochloride
Thionyl chloride (216 gm) was slowly added to a mixture of (S)-2-amino-3-
phenylpropanoic acid (200 gm) and methanol (1000 ml) at 25-30°C and the obtained reaction
mixture was stirred for 8 hrs at 45-50°C. Distilled off the solvent and excess thionyl chloride
from the reaction mixture under reduced pressure. Cooled the reaction mixture to 25-30°C,
methyl tert.butyl ether (800 ml) was added and stirred for 1 hr at the same temperature.
Filtered the solid, washed with methyl tert.butyl ether and dried to get the title compound.
Yield: 256.5 gm; M.R: 151-157°C; Purity by HPLC: 99.9%.
Example-2: Preparation of (S)-methyl 2-((S)-2-amino-4-methylpentanamido)-3-
phenylpropanoate hydrochloride
Hydroxybenzotriazole (10.8 gm) followed by N-methylmorpholine (81.2 gm) were added to a pre-cooled mixture of (S)-methyl 2-amino-3-phenylpropanoate hydrochloride (86.2 gm), (S)-2-(tert-butoxycarbonylamino)-4-methylpentanoic acid (100 gm) and dichloromethane (700 ml) at 0-5°C under nitrogen atmosphere. A solution of dicyclohexylcarbodiimide (99.2 gm) in dichloromethane (300 ml) was slowly added to the reaction mixture at 0-5°C. Raised the temperature of the reaction mixture to 25-30°C and stirred for 2 hrs at the same temperature. Filtered the reaction mixture and cooled the filtrate to 10-15°C. Washed the filtrate with aqueous sodium bicarbonate solution followed by with water. Distilled off the solvent completely from the reaction mixture under reduced pressure. Isopropyl alcohol (200 ml) was added to the obtained compound at 25-30°C. Isopropyl alcohol-HCl (1300 ml) was added to the reaction mixture at 25-30°C and stirred the reaction mixture for 2 hrs at the same temperature. Filtered the precipitated solid, washed with methyl tert.butyl ether and dried the material to get the title compound. Yield: 81.0 gm; M.R: 190-196°C.
Example-3: Preparation of (S)-methyl 2-((S)-2-((S)-2-amino-4-phenylbutanamido)-4-methylpentanamido)-3-phenylpropanoate hydrochloride
Hydroxybenzotriazole (4.5 gm) followed by N-methylmorpholine (33.8 gm) were added to a pre-cooled mixture of (S)-methyl.2-((S)-2-amino-4-methylpentanamido)-3-phenyl

propanoate hydrochloride (55 gm), (S)-2-(tert-butoxycarbonylamino)-4-phenylbutanoic acid (51.3 gm) and dichloromethane (385 ml) at 0-5°C under nitrogen atmosphere. A solution of dicyclohexylcarbodiimide (41.3 gm) in dichloromethane (165 ml) was slowly added to the reaction mixture at 0-5°C. Raised the temperature of the reaction mixture to 25-30°C and stirred for 2 hrs at the same temperature. Filtered the reaction mixture and cooled the filtrate to 10-15°C. Washed the filtrate with aqueous sodium bicarbonate solution followed by with water. Distilled off the solvent completely from the reaction mixture under reduced pressure. Isopropyl alcohol (825 ml) was added to the obtained compound at 25-30°C. Heated the reaction mixture to 80-85°C and stirred for 1 hr at the same temperature. Cooled the reaction mixture to 25-30°C and stirred the reaction mixture for 1 hr at the same temperature. Filtered the solid, washed with methyl tert.butyl ether. Ethyl acetate (220 ml) was added to the obtained solid at 25-30°C. Ethyl acetate-HCl (715 ml) was slowly added to the reaction mixture at 25-30°C and stirred the reaction mixture for 2 hrs at the same temperature. Filtered the precipitated solid, washed with methyl tert.butyl ether and then dried to get the title compound. Yield: 58.0 gm; M.R: 235-241°C.
Example-4: Preparation of (S)-2-((S)-4-methyl-2-((S)-2-(2-morpholinoacetamido)-4-phenylbutanamido)pentanamido)-3-phenylpropanoic acid (Formula-2)
Hydroxybenzotriazole (4.1 gm) followed by N-methylmorpholine (31 gm) were added to a pre-cooled mixture of (S)-methyl 2-((S)-2-((S)-2-amino-4-phenylbutanamido)-4-methylpentanamido)-3-phenylpropanoate hydrochloride (75 gm), 2-morpholinoacetic acid hydrochloride (30.4 gm) and dichloromethane (525 ml) at 0-5°C under nitrogen atmosphere. A solution of dicyclohexylcarbodiimide (37.9 gm) in dichloromethane (225 ml) was slowly added to the reaction mixture at 0-5°C. Slowly raised the temperature of the reaction mixture to 25-30°C and stirred for 2 hrs at the same temperature. Filtered the reaction mixture and cooled the filtrate to 10-15°C. Washed the filtrate with aqueous sodium bicarbonate solution followed by with aqueous hydrochloric acid solution and then with water. Distilled off the solvent completely from the reaction mixture under reduced pressure. Tetrahydrofuran (750 ml) followed by water (375 ml) were added to the obtained compound at 25-30°C and cooled the reaction mixture to 10-15°C. A solution of lithium hydroxide monohydrate (12.9 gm) in

water (75 ml) was added to the reaction mixture at 10-15°C. Raised the temperature of the reaction mixture to 25-30°C and stirred for 3 hrs at the same temperature. Water and dichloromethane were added to the reaction mixture at 25-30°C and stirred for 5 min. Both the organic and aqueous layers were separated and washed the aqueous layer with dichloromethane. Acidified the aqueous layer with aqueous hydrochloric acid solution at 25-30°C and stirred the reaction mixture for 1 hr at the same temperature. Filtered the precipitated solid and washed with water. Methanol (450 ml) was added to the obtained solid at 25-30°C. Heated the reaction mixture to 55-60°C and stirred for 45 min at the same temperature. Cooled the reaction mixture to 25-30°C and stirred for 1 hr at the same temperature. Filtered the solid, washed with methanol and dried to get the title compound. Yield: 47.6 gm; MR: 209-210°C.
Example-5: Preparation of (S)-2,5-dioxopyrrolidin-l-yl 2-((S)-4-methyl-2-((S)-2-(2-morpholinoacetamido)-4-phenylbutanamido)pentanamido)-3-phenylpropanoate
(Formula-3a)
A solution of diisopropyl carbodiimide (6.12 gm) in dichloromethane (75 ml) was slowly added to a mixture of (S)-2-((S)-4-methyl-2-((S)-2-(2-morpholinoacetamido)-4-phenylbutanamido)pentanamido)-3-phenylpropanoic acid compound of formula-2 (25 gm), N-hydroxy succinimide (5.6 gm) and dichloromethane (250 ml) at 25-30°C under nitrogen atmosphere and stirred the reaction mixture for 4 hrs at the same temperature. Cooled the reaction mixture to 0-5°C and stirred for 2 hrs at the same temperature. Filtered the reaction mixture and distilled off the solvent completely from the filtrate under reduced pressure to get the title compound as a solid. Yield: 26.5 gm.
Example-6: Preparation of (S)-2-(tert-butoxycarbonylamino)-4-methylpentanoic acid
monohydrate
(S)-2-Amino-4-methyl pentanoic acid (100 gm) was added to a solution of sodium hydroxide (36.6 gm) in water (800 ml) at 25-30°C and stirred the reaction mixture for 15 min at the same temperature. Di-tert-butyl dicarbpnate (200 gm) was slowly added to the reaction mixture lot wise at 25-30°C and stirred the reaction mixture for 20 hrs at the same

temperature. Acidified the reaction mixture using aqueous hydrochloric acid solution at 25-30°C and stirred for 30 min at the same temperature. Filtered the precipitated solid and washed with water. Methanol (300 ml) was added to the obtained solid at 25-30°C and stirred the reaction mixture for 15 min at the same temperature. Water (500 ml) was slowly added to the reaction mixture at 25-30°C and stirred for 1 hr at the same temperature. Filtered the precipitated solid, washed with water and dried to get the title compound. Yield: 155.0 gm.
Example-7: Preparation of (S)-tert-butyl l-(methoxy(methyl)amino)-4-methyl-l-oxopentan-2-ylcarbamate
N-Methylmorpholine (55.1 ml) was added to a pre-cooled solution of (S)-2-(tert-butoxycarbonylamino)-4-methylpentanoic acid monohydrate (50 gm) in dichloromethane (350 ml) at -10°C to -15°C under nitrogen atmosphere. Ethyl chloroformate (22.9 ml) was slowly added to the reaction mixture at -10°C to -15°C and stirred for 20 min at the same temperature. N,0-dimethylhydroxylamine hydrochloride (23.5 gm) was slowly added to the reaction mixture at -10°C to -15°C and stirred for 2 hrs at the same temperature. Raised the temperature of the reaction mixture to 0-5°C, quenched the reaction mixture with water and stirred for 15 min at the same temperature. Both the organic and aqueous layers were separated and washed the organic layer with 10% aqueous sodium bicarbonate solution. Distilled off the solvent completely from the organic layer under reduced pressure to get the title compound. Yield: 48.0 gm.
Example-8: Preparation of (S)-tert-butyl 2,6-dimethyl-3-oxohept-l-en-4-ylcarbamate
A mixture of magnesium (24 gm), iodine (0.5 gm) and tetrahydrofuran (1000 ml) was heated to 50-55°C under nitrogen atmosphere. A solution of 2-bromo propene (123.5 gm) in tetrahydrofuran (250 ml) was slowly added lot wise to the reaction mixture at 50-55°C and stirred the reaction mixture for 2 hrs 30 min at the same temperature. Cooled the reaction mixture to 25-30°C and the resulting reaction mixture was added to a pre-cooled mixture of (S)-tert-butyl l-(methoxy(methyl)amino)-4-methyl-l-oxopentan-2-ylcarbamate (50 gm) and tetrahydrofuran at 0-5 °C and stirred the reaction mixture for 15 min at the same temperature.

Raised the temperature of the reaction mixture to 25-30°C and stirred for 8 hrs at the same temperature. The obtained reaction mixture was slowly added to pre-cooled aqueous ammonium chloride solution at 0-5°C and stirred for 30 min at the same temperature. Neutralized the reaction mixture using aqueous hydrochloric acid solution and stirred the reaction mixture for 15 min. Both the organic and aqueous layers were separated and the aqueous layer was extracted with ethyl acetate. Combined the organic layers and distilled off the solvent completely under reduced pressure. Dichloromethane was added to the obtained compound at 25-30°C and stirred for 5 min. Silica gel was added to the reaction mixture and distilled off the solvent completely from the reaction mixture. Cooled the obtained compound to 25-30°C, cyclohexane (247.5 ml) and ethyl acetate (2.5 ml) were added and stirred the reaction mixture for 45 min at the same temperature. Filtered the reaction mixture and distilled off solvent completely from filtrate under reduced pressure to get title compound. Yield: 38.5 gm.
Example-9: Preparation of tert-butyl (S)-4-methyl-l-((R)-2-methyloxiran-2-yl)-l-oxopentan-2-ylcarbamate(Formula-5)
A mixture of (S)-tert-butyl 2,6-dimethyl-3-oxohept-l-en-4-ylcarbamate (50 gm), methanol (1250 ml) and potassium carbonate (13.5 gm) was stirred for 15 min at 25-30°C. Benzonitrile (10.1 gm) was added to the reaction mixture and cooled to 0-5°C. 50% hydrogen peroxide (1.6 gm) was slowly added to the reaction mixture at 0-5°C and raised the temperature of the reaction mixture to 25-30°C. Second lot of 50% hydrogen peroxide (25 gm) was slowly added to the reaction mixture at 25-30°C and stirred for 6 hrs at the same temperature. The obtained reaction mixture was slowly added to a pre-cooled mixture of sodium thiosulfate and water at 0-5°C and stirred the reaction mixture for 20 min at the same temperature. Raised the temperature of the reaction mixture to 25-30°C, dichloromethane was added and stirred for 15 min at the same temperature. Both the organic and aqueous layers were separated and the organic layer was washed with aqueous sodium thiosulfate solution. Distilled off the solvent completely from the organic layer under reduced pressure and the obtained compound was purified by column chromatography using ethyl acetate: cyclohexane as eluent. Yield: 16.5 gm.

Example-10: Preparation of (2S)-N-((S)-l-((S)-4-methyl-l-((R)-2-methyloxiran-2-yl)-l-oxopentan-2-ylcarbamoyl)-2-phenylethyl)-2-((S)-2-(2-morpholinoacetamido)-4-phenyl
butanamido)-4-methyIpentanamide (Formula-1)
Tert-butyl (S)-4-methyl-1 -((R)-2-methyloxiran-2-yl)-1 -oxopentan-2-ylcarbamate
compound of formula-5 (10 gm) was added to a solution of trifluoroacetic acid (30 ml) in dichloromethane (70 ml) at 5-10°C under nitrogen atmosphere and stirred the reaction mixture for 3 hrs at the same temperature. Distilled off the solvent completely from the reaction mixture and the residue obtained was dissolved in dichloromethane. Aqueous sodium carbonate solution was added to the reaction mixture at 25-30°C and stirred for 20 min at the same temperature. Filtered the reaction mixture and both the organic and aqueous layers were separated from the filtrate. (S)-2,5-dioxo pyrrblidin-1-yl 2-((S)-4-methyl-2-((S)-2-(2-morpholinoacetamido)-4-phenylbutanamido)pentanamido)-3-phenylpropanoate compound of formula-3a (25 gm) and dichloromethane (120 ml) were added to the above organic layer and stirred the reaction mixture for 60 min at the same temperature. Water was added to the reaction mixture and stirred for 5 min. Both the organic and aqueous layers were separated and the aqueous layer was extracted with dichloromethane. Combined the organic layers and washed with 5% aqueous sodium bicarbonate solution followed by with 5% aqueous sodium chloride solution. Distilled off the solvent completely from the organic layer under reduced pressure and purified the obtained compound by column chromatography using methanol:dichloromethane as eluent to get the title compound. The obtained compound was purified by preparative HPLC using acetonitrile:water as eluent. Yield: 19.0 gm.
Example-11: Preparation of (S)-perfluorophenyl 2-((S)-4-methyl-2-((S)-2-(2-morphoIino acetamido)-4-phenylbutanamido)pentanamido)-3-phenylpropanoate
14Bis(dime%lamino)methylene]-lH-l,2,3-triazolo[4,5-b]pyridinium 3-oxid
hexafluorophosphate (22.3 gm) and hydroxybenzotriazole (1.4 gm) were added to a pre-cooled mixture of (S)-2-((S)-4-methyl-2-((S)-2-(2-morpholinoacetamido)-4-phenyl butanamido)pentanamido)-3-phenylpropanoic acid (30 gm) and dichloromethane (300 ml) at 10-15°C under nitrogen atmosphere. A solution of 2,3,4,5,6-pentafluorophenol (11.7 gm) in dichloromethane (90 ml) was added to the reaction mixture at 10-15°C. A solution of

N-methylmorpholine (6.4 gm) in dichloromethane (60 ml) was slowly added to the reaction mixture at 10-15°C and stirred for 45 min at the same temperature. Aqueous sodium bicarbonate solution was added to the reaction mixture at 10-15»C and stirred for 5 min at the same temperature. Filtered the reaction mixture, both the organic and aqueous layers were separated and washed the organic layer with water. Silica was added to the organic layer and stirred for 10 min. Filtered the reaction mixture through hyflow bed and washed the hyflow bed with dichloromethane. Distilled off the solvent completely from the organic layer and co-distilled with methyl tert.butyl ether. 180 ml of methyl tert.butyl ether was added to the obtained solid at 25-30°C and stirred the reaction mixture for 40 min at the same temperature. Filtered the solid, washed with methyl tertbutyl ether and then dried the material to get title compound. Yield: 27.0 gm; M.R: 155-162°C.
Example-12: Preparation of (2S)-N-((S)-l-((S)-4-methyl-l-((R)-2-methyloxiran-2-yl)-l-oxopentan-2-ylcarbamoyl)-2-Phenylethyl)-2-((S)-2-(2-morpholinoacetamido)-4-phenyl
butanamido)-4-methylpentanamide(Formula-l)
Tert-butyl(S)-4-methyl-l-((R)-2-methyloxiran-2-yl)-l-oxopentan-2-ylcarbamate(37
gm) was added to a pre-cooled mixture of trifluoroacetic acid (92.3 gm) and dichloromethane
(300 ml) at 0-5°C and stirred the reaction mixture for 3 hrs at the same temperature. D.stilled
off the solvent completely from the reaction mixture under reduced pressure. The obtained
compound was dissolved in dichloromethane (300 ml) at 25-30°C. Cooled the reaction
mixture to 10-15°C, sodium carbonate (43.4 gm) was slowly added and stirred for 10 min at
the same temperature. Filtered the reaction mixture and the filtrate was added to a solution of
(S)-perfluorOPhenyl 2-((S)-4-methyl-2-((S)-2-(2-morpholinoacetamido)-4-phenyl
butanamido)pentanamido)-3-phenylprOPanoate (100 gm) in dichloromethane (300 ml) at 25-30°C and stirred the reaction mixture for 3 hrs at the same temperature. Water was added to the reaction mixture at 25-30°C and stirred for 10 min at the same temperature. Both the organic and aqueous layers were separated and distilled off 60% of solvent from the organic layer under reduced pressure. The obtained solution was charged into a column loaded with silica gel Run the column with dichloromethane and the product was eluted with dichloromethane:methanol (9:1) as eluent The pure fractions were collected and distilled off

the solvent under reduced pressure to get the title compound as solid. The obtained compound was purified by preparative HPLC using acetonitrile:water as eluent. Yield: 58.0 gm.
Example-13: Preparation of compound of formula-1
(S)-2-Amino-4-methyl-1 -((R)-2-methyloxiran-2-yl)pentan-1 -one trifluoroacetic acid salt (47 gm) was added to a pre-cooled solution of (S)-2-((S)-4-methyl-2-((S)-2-(2-morpholinoacetamido)-4-phenylbutanamido)pentanamido)-3-phenylpropanoic acid (100 gm) and N,N-dimethylformamide (1000 ml) at 0-5°C under nitrogen atmosphere. l-[bis(dimethylamino)methylene]-lH-l,253-triazolo[455-b]pyridinium 3-oxid hexafluoro phosphate (74 gm), hydroxybenzotriazole (4 gm) and N-methylmorpholine (38.4 ml) were added to the reaction mixture at 0-5°C and stirred for 3 hrs at the same temperature. Aqueous sodium bicarbonate solution and ethyl acetate were added to the reaction mixture at 10-15 °C and stirred for 10 min at the same temperature. Both the organic and aqueous layers were separated and extracted the aqueous layer with ethyl acetate. Combined the organic layers and washed with water. Distilled off the solvent completely from the organic layer under reduced pressure. Methanol (800 ml) was added to the obtained compound at 25-30°C. Heated the reaction mixture to 55-60°C and water (800 ml) was added at the same temperature. Cooled the reaction mixture to 25-3 0°C and stirred for 2 hrs at the same temperature. Filtered the precipitated solid, washed with water and then dried the material to get pure title compound. Yield: 100.0 gm.

We Claim:

1. A process for the preparation of (2S)-N-((S)-l-((S)-4-methyl-l-((R)-2-methyloxiran-2-yl)4-oxopentan-2-ylcarbamoyl)-2-phenyk phenylbutanamido)-4-methylpentanamide compound of formula-1, comprising of;
a) Reacting the (S)-2-((S)-4-methyl-2-((S)-2-(2-morpholinoacetamido)-4-phenyl
butanamido)pentanamido)-3-phenylpropanoic acid compound of formula-2 with
compound of general formula Ri-OH in a suitable solvent in presence of a suitable
coupling agent and/or a suitable base to provide compound of general formula-3

b) optionally isolating the compound of general formula-3 as a solid,
c) reacting the compound of general fomula-3 with (S)-2-amino-4-methyl-l-((R)-2-methyloxiran-2-yl)pentan-l-one compound of formula-4 or its acid-addition salt

in a suitable solvent optionally in presence of a suitable base to provide compound of formula-1.

2. A process according to claim 1, wherein
in step-a) the suitable coupling agent is selected from l,l'-carbonyldiimidazole, N,N'-dicyclohexylcarbodiimide, N,N'-diisopropyl carbodiimide, l-ethyl-3-(3-dimethyl aminopropyl)carbodiimide hydrochloride, 1 -[bis(dimethylamino)methylene] -1H-1,2,3 -triazolo[4,5-b]pyridinium 3-oxid hexafluorophosphate (HATU), 2-(lH-benzotriazol-l-yl)-1,1,3,3 -tetramethyluronium hexafluorophosphate (HBTU), 1 H-benzotriazolium 1 -[bis(dimethylamino)methylene]-5chloro-hexafluorophosphate(l -)3-oxide (HCTU), 0-(benzotriazol-1 -yl)-N,N,N*,N'-tetramethyl uronium tetrafluoroborate (TBTU), alkyl/aryl haloformates; diphenylphosphoroazidate, thionyl chloride, oxalyl chloride, phosphorous oxychloride, phosphorous pentachloride, 4-methyl-2-oxopentanoyl chloride (i*BuCOCOCl), (benzotriazol-1 -yloxy)tris(dimethylamino)phosphonium hexafluoro phosphate (BOP), benzotriazol-1-yl-oxytripyrrolidinophosphonium hexafluorophosphate (PyBOP), methanesulfonyl chloride, p-toluenesulfonyl chloride.
in step-a) & step-c) the suitable base is selected from organic bases, inorganic bases, prganolithium bases, organosilicon bases or their mixtures; suitable solvent is selected from hydrocarbon solvents, ether solvents, ester solvents, polar-aprotic solvents, chloro solvents, ketone solvents, nitrile solvents, alcohol solvents, polar solvents or their mixtures.

3. A process for the preparation of (2S)-N-((S)-l-((S)-4-methyl-l-((R)-2-methyloxiran-2-
yl)-l-oxopentan-2-ylcarbamoyl)-2-phenylethyl)-2-((S)-2-(2-morpholinoacetamido)-4-
phenylbutanamido)-4-methylpentanamide compound of formula-1, comprising of;
a) Reacting the (S)-2-((S)-4-methyl-2-((S)-2-(2-morpholinoacetamido)-4-phenyl butanamido)pentanamido)-3-phenylpropanoic acid compound of formula-2 with N-hydroxy succinimide in a suitable solvent in presence of a suitable coupling agent and/or a suitable base to provide (S)-2,5-dioxopyrrolidin-l-yl 2-((S)-4-methyl-2-((S)-2-(2-morpholinoacetamido)-4-phenylbutanamido)pentanamido)-3-phenyl propanoate
compound of formula-3 a,


b) optionally isolating the compound of formula-3a as solid,
c) reacting the compound of fomula-3a with (S)-2-amino-4-methyl-l-((R)-2-methyloxiran-2-yl)pentan-l-one compound of formula-4 or its acid-addition salt in a suitable solvent optionally in presence of a suitable base to provide compound of formula-1.

4. Compounds represented by the structural formula


6. A process for the preparation of compound of general formula-3 comprising of, reacting the (S)-2-((S)-4-methyl-2-((S)-2-(2-morpholinoacetamido)-4-phenyl butanamido)pentanamido)-3-phenylpropanoic acid compound of formula-2 with compound of general formula Ri-OH in a suitable solvent in presence of a suitable coupling agent and/or a suitable base to provide compound of general formula-3.
7. A process for the preparation of (2S)-N-((S)-l-((S)-4-methyl-l-((R)-2-methyloxiran-2-yl)-l-oxopentan-2-ylcarbamoyl)-2-phenylethyl)-2-((S)-2-(2-morpholinoacetamido)-4-phenylbutanamido)-4-methylpentanamide compound of formula-1, comprising of reacting the compound of general formula-3,with (S)-2-amino-4-methyl-l-((R)-2-methyloxiran-2-yl)pentan-l-one of formula-4 or its salt in a suitable solvent optionally in presence of a suitable base to provide compound of formula-1.

8. A process according to claim 7, wherein the suitable base is selected from organic bases, inorganic bases, organolithium bases and organosilicon bases or their mixtures; and the suitable solvent is selected from hydrocarbon solvents, ether solvents, ester solvents, polar-aprotic solvents, chloro solvents, ketone solvents, nitrile solvents, alcohol solvents, polar solvents or their mixtures.

9. A process for the preparation of (2S)-N-((S)-l-((S)-4-methyl-l-((R)-2-methyloxiran-2. yl)4-oxopentan-2-ylcarbamoyl)-2-phenylethyl)-2-((S)-2-(2-morpholinoacetamido)-4-
phenylbutanamido)-4-methylpentanamide compound of formula-1, comprising of reacting the (S)-2,5-dioxopyrrolidin-l-yl 2-((S)-4-methyl-2-((S)-2-(2-morpholino acetamido)-4-phenylbutanamido)pentanamido)-3-phenyl propanoate compound of formula-3 a with (S)-2-amino-4-methyl-1 -((R)-2-methyloxiran-2-yl)pentan-1 -one compound of formula-4 or its acid-addition salt in a suitable solvent optionally in presence of a suitable base to provide compound of formula-1.
10. Solid state form of (S)-2,5-dioxopyrrolidin-l-yl 2-((S)-4-methyl-2-((S)-2-(2-morpholinoacetamido)-4-phenylbutanamido)pentanamido)-3-phenylpropanoate.