Reaction #82343

Reaction equation

dicyclohexylcarbodiimide

hydroxybenzotriazole

N-ethylmorpholine

N2 [3(S)-amino-2(R)-hydroxy-4-phenylbutyl]-N1 -phenyl-L-prolinamide

N-(benzyloxycarbonyl)-L-asparagine

→

N2 [3(S)-[[N-(benzyloxycarbonyl)-L-asparaginyl]amino]-2(R)-hydroxy-4-phenylbutyl]-N1 -phenyl-L-prolinamide

Yield 42.3%

Solvents

ethyl acetate

tetrahydrofuran

Conditions

Workup

1. 1
   Filtrationfiltered
2. 2
   WashThe filtrate was washed with sodium bicarbonate solution and sodium chloride solution
3. 3
   Otherthe solvent was then removed by evaporation
4. 4
   OtherThe residue was chromatographed on silica gel
5. 5
   Washfor the elution

Procedure

0.208 g of dicyclohexylcarbodiimide, 0.124 g of hydroxybenzotriazole and 0.106 g of N-ethylmorpholine were added to a stirred solution of 0.315 g of N2 -[3(S)-amino-2(R)-hydroxy-4-phenylbutyl]-N1 -phenyl-L-prolinamide and 0.244 g of N-(benzyloxycarbonyl)-L-asparagine in 10 ml of tetrahydrofuran at 0° C. The mixture was stirred for 16 hours, then diluted with ethyl acetate and filtered. The filtrate was washed with sodium bicarbonate solution and sodium chloride solution and the solvent was then removed by evaporation. The residue was chromatographed on silica gel using dichloromethane/methanol (9:1) for the elution to give 0.22 g of N2 -[3(S)-[[N-(benzyloxycarbonyl)-L-asparaginyl]amino]-2(R)-hydroxy-4-phenylbutyl]-N1 -phenyl-L-prolinamide in the form of a white solid of melting point 169°-171° C. (from methanol).

Source