AN IMPROVED METHOD FOR BENZIMIDAZOLE SYNTHESIS FROM 2-HALOANILINE, DIHALOMETHANE AND SODIUM AZIDE IN PRESENCE OF COPPER COMPLEX CATALYST

摘要

Present invention gives an improved method for the synthesis of benzimidazole using sodium azide and dihalomethane. This invention reports highly efficient one step, three component process for the synthesis of benzimidazole from 2-haloanilines, dihalomethane and sodium azide in presence of copper complex. The Copper salt was used as a catalyst which binds with nitrogen donating bidentate ligand, at 100-150°C for 12-36 h and in the presence of dimethyl sulphoxide as a solvent. The process uses dihalomethane as a novel source of carbon and sodium azide as a source of nitrogen elements. The process is novel as it uses first time dihalomethane as a carbon source for the benzimidazole synthesis. This method gives 50-80% yield of corresponding benzimidazoles with different carbon sources.