Acetonitrile → Dicyclohexylcarbodiimide

Participants

Reaction Steps

Prolinamide hydrochloride (6 g.) and N-t-butyloxycarbonyl-Nim -benzylhistidine (13.8 g.) were reacted in 200 ml. acetonitrile in the presence of 4.04 g. triethylamine and 10.3 g N,N'-dicyclohexylcarbodiimide to give N-t-butyloxycarbonyl-Nim -benzyl-histidyl-prolinamide as an oily residue. The oil was dissolved in 150 ml. of 2N hydrobromic acid solution in glacial acetic acid. The solution was kept at room temperature for 1 hour in a stoppered flask and then poured into 1500 ml. anhydrous ether. The solid precipitate was redissolved in methanol and precipitated again with ether to give 13.2 g (65.6%) of crystalline Nim -benzyl-histidyl-prolinamide dihydrobromide melting at 196- 8°C after recrystallization from methanol-ether.

Provenance & Evidence