反应详情

To a stirred solution of [(R)-1-(N-Benzyl-carbamimidoyl)-2-methyl-propyl]-carbamic acid t-butyl ester (14.16 g, 46 mMol) in EtOH (50 mL) was added Ethyl 2-ethoxyethylidene-cyanoacetate (8.4 g, 46 mMol). The reaction was refluxed for 18 h, cooled to RT and concentrated under vacuum. Purification by flash chromatography on silica gel (5% EtOAc, CH2Cl2) followed by crystallization from EtOAc, hexane and Et2O, pet. ether gave the title compound (8.03 g, 44%) as a white solid: MS (ES) m/e 397.2 (M+H)+.

1. temperatureThe reaction was refluxed for 18 h
2. concentrationconcentrated under vacuum
3. customPurification by flash chromatography on silica gel (5% EtOAc, CH2Cl2)
4. customfollowed by crystallization from EtOAc, hexane and Et2O, pet. ether