Deep eutectic solvent promoted highly efficient synthesis of N, N'-diarylamidines and formamides

摘要

A deep eutectic solvent was used as a dual catalyst and reaction medium for the efficient N-formylation of aromatic amines without hazardous organic solvent and catalyst. Treatment of aromatic amines with trimethyl orthoformate and formic acid in deep eutectic solvent at 70 °C gives the corresponding N-formyl derivatives in good to excellent yields. This simple ammonium deep eutectic solvent, easily synthesized from choline chloride and SnCl2, with 100% atom economy and making it applicable to industry and laboratory. Furthermore, j heating the trimethyl orthoformate and aromatic primary amines in the deep eutectic solvent results in formation of the corresponding N,N'-diarylamidines in high yields.