A versatile way for the synthesis of monomethylamines by reduction of N-substituted carbonylimidazolides with NaBH4/I2 system

An economical and versatile protocol for the one-pot synthesis of monomethylamines by reduction of the N -substituted carbonylimidazolides with NaBH 4 /I 2 in THF at reflux was described. By this method, no special catalyst is used and various monomethylamines can be easily obtained in a moderate to good yield from a wide range of raw materials including amines (primary amines and secondary amines), carboxylic acids and isocyanates. Besides, interesting reduction selectivity was demostrated. Exploration of the reaction process shows that it undergoes a two-step pathway via the formamide intermediate and the reduction of the formamide intermediate to monomethylamine is the rate-determining step. This work can contribute significantly to better expanding the application of the N-substituted carbonylimidazolides.