1,3-Propanediamine, N'-(ethylcarbonimidoyl)-N,N-dimethyl-, monohydrochloride → 2(R)-[1(S)-(tert-butoxycarbonyl)-4-phenyl-3-butenyl]-4-methyl-N-(4-benzyloxycarbonyl-2,6-dioxo-1-piperazinyl)valeramide

Participants

Reaction Steps

A solution of 0.7 g of 2,6-dioxo-4-morpholine carboxylic acid benzyl ester in 20 ml of dichloromethane was treated with 1.0 g of (E)-2(R)-[1(S)-(tert-butoxycarbonyl)-4-phenyl-3-butenyl]-4-methylvalerohydrazide (prepared as described in Example 1). The mixture was stirred for 1 hour at room temperature and then treated with 0.53 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride. The mixture was stirred for a further 3 hours at room temperature and then washed in sequence with 2M aqueous hydrogen chloride, 5% aqueous sodium hydrogen carbonate and saturated aqueous sodium chloride. Drying of the organic phase over anhydrous magnesium sulphate and evaporation gave a residue which was purified by column chromatography on silica gel using ethyl acetate/ hexane (3:7) for the elution to give 1.16 g of 2(R)-[1(S)-(tert-butoxycarbonyl)-4-phenyl-3-butenyl]-4-methyl-N-(4-benzyloxycarbonyl-2,6-dioxo-1-piperazinyl)valeramide in the form of a white solid.

Provenance & Evidence