Carbamoylimidazolium and thiocarbamoylimidazolium salts: novel reagents for the synthesis of ureas, thioureas, carbamates, thiocarbamates and amides
作者:Justyna A. Grzyb、Ming Shen、Chiaki Yoshina-Ishii、W. Chi、R.Stanley Brown、Robert A. Batey
DOI:10.1016/j.tet.2005.05.056
日期:2005.7
Carbamoylimidazolium salts act as efficient N,N-disubstituted carbamoylating reagents. These salts are readily prepared by the sequential treatment of secondary amines with N,N′-carbonyldiimidazole (CDI) and iodomethane. The carbamoylimidazolium salts are more efficient carbamoyl transfer reagents than the intermediate carbamoylimidazoles, as a result of the ‘imidazolium’ effect. Kinetic studies on
氨基甲酰咪唑鎓盐可作为有效的N,N-二取代的氨基甲酰化试剂。这些盐很容易通过用N,N依次处理仲胺来制备′-羰基二咪唑(CDI)和碘甲烷。由于“咪唑鎓”效应,因此氨基甲酰咪唑鎓盐是比中间氨基甲酰咪唑更有效的氨基甲酰转移试剂。对氨基甲酰咪唑盐和氨基甲酰咪唑鎓盐的碱促进水解的动力学研究表明,其加速百倍。该盐与胺,硫醇,酚/醇和羧酸以高收率反应,而无需对产物进行后续色谱纯化,分别生产尿素,硫代氨基甲酸酯,氨基甲酸酯和酰胺。还从仲胺和N,N′-硫代羰基二咪唑(TCDI)合成类似的硫代氨基甲酰咪唑鎓盐,然后用碘代甲烷甲基化。