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

Participants

Reaction Steps

354 mg (1.7 mmol) of 4-(2-methoxycarbonylethyl)benzoic acid (step b) and 500 mg (1.7 mmol) of tert-butyl (2S)-2-benzyloxycarbonylamino-3-aminopropionate were dissolved in 3 ml of dimethylformamide and treated with 557 mg (1.7 mmol) of O-((cyano(ethoxycarbonyl)methylene)amino)-1,1,3,3-tetramethyluronium tetrafluoroborate (TOTU) and 204 mg (1.7 mmol) of diisopropylethylamine and the solution was stirred at room temperature for 7 h. The solvent was evaporated in vacuo, the residue was dissolved in ethyl acetate and washed three times each with a solution of potassium hydrogen sulfate and a solution of sodium bicarbonate until neutral. The organic phase was separated off and dried, and the solvent was distilled off in vacuo. Yield: 770 mg (93%).

Provenance & Evidence