Diisopropylethylamine → tert-butyl (2S)-2-benzyloxycarbonylamino-3-(4-(2-methoxycarbonylethyl)benzoylamino)propionate

Participants

Reaction Steps

354 mg (1.7 mmol) of 4-(2-methoxycarbonyl-ethyl)benzoic acid and 500 mg (1.7 mmol) of tert-butyl (2S)-3-amino-2-benzyloxycarbonylaminopropionate were dissolved in 3 ml of dimethylformamide and treated with 557 mg (1.7 mmol) of O-((cyano-(ethoxycarbonyl)-methylidene)amino)-1,1,3,3-tetramethylu ronium tetrafluoroborate (TOTU) and 204 mg (1.7 mmol) of diisopropylethylamine, and the mixture was stirred at room temperature for 7 hours at pH 7-8. The solvent was removed in vacuo, the residue was dissolved in ethyl acetate and the solution was washed three times each with KHSO4 solution and NaHCO3 solution until neutral. The organic phase was separated off and dried and the solvent was removed by distillation in vacuo. Yield 770 mg. MS (ES+): m/e=485.2 (M+H+).

Provenance & Evidence