反应详情

0.122 g of N-(benzyloxycarbonyl)-3-cyano-L-alanine was dissolved in 2 ml of dry dimethylformamide. The solution was stirred and cooled in an ice/salt bath and treated with 0.066 g of hydroxybenzotriazole and 0.1 g of dicyclohexylcarbodiimide. The mixture was stirred for 5 minutes and then treated with 0.163 g of N2 -[3(S)-amino-2(R)-hydroxy-4-phenylbutyl]-N1 -tert.butyl-L-prolinamide in 2.5 ml of dry dichloromethane. The mixture was allowed to warm to room temperature and was then stirred overnight. The resulting dicyclohexylurea was filtered off and washed with methylene chloride. The combined filtrate and washings were evaporated at 40° C. in a vacuum to give an oil which was partitioned between ethyl acetate and water. The organic phase was washed in sequence with saturated aqueous sodium bicarbonate solution and saturated sodium chloride solution and then dried over sodium sulphate. The solvent was removed by evaporation to give an oil which was chromatographed on silica gel using 14% methanol in dichloromethane for the elution. There were thus obtained 50 mg of product which was recrystallized from diethyl ether/n-hexane to give 0.045 g of N2 -[3(S)-[[N-(benzyloxycarbonyl)-3-cyano-L-alanyl]amino]-2(R)-hydroxy-4-phenylbutyl]-N1 -tert.butyl-L-prolinamide hemihydrate as a solid of melting point 65°-70° C. (softening).

1. temperaturecooled in an ice/salt bath
2. stirringThe mixture was stirred for 5 minutes
3. stirringwas then stirred overnight
4. filtrationThe resulting dicyclohexylurea was filtered off
5. washwashed with methylene chloride
6. customThe combined filtrate and washings were evaporated at 40° C. in a vacuum
7. customto give an oil which
8. customwas partitioned between ethyl acetate and water
9. washThe organic phase was washed in sequence with saturated aqueous sodium bicarbonate solution and saturated sodium chloride solution
10. dry with materialdried over sodium sulphate
11. customThe solvent was removed by evaporation
12. customto give an oil which
13. customwas chromatographed on silica gel using 14% methanol in dichloromethane for the elution
14. customwas recrystallized from diethyl ether/n-hexane