Synthesis Of Benzoazoles In Water

Benzoazoles have gained considerable attention in the past few years, due to their ever-increasing and undeniable roles in the fields of drugs and natural products. Thus, constant efforts have been devoted to develop new methods for the synthesis of their frameworks. Although numerous methods have been reported in the literature, the reported methodologies usually require catalysts and toxic organic solvents, which potentially introduce serious hazardous materials into the ecosystem Therefore, it is crucial to develop a more efficient, economic and eco-friendly synthetic method for benzoazoles. Water is cheap, abundant, noninflammable and environmentally benign and has received considerable attention as an essential component of the development of Green Chemistry.The main content of this paper includes the following two parts:1. A simple one-pot reaction system for the synthesis of benzoazoles containing aminophenyl group in water has been developed. The reaction was performed between nitrobenzaldehyde and 2-aminothiophenols,2-aminoanilines or 2-aminophenols respectively, in the presence of SnCl2·2H2O as the reductant under air, providing 12 products efficiently with the highest yield up to 83%.2. An efficient, environmentally benign and economical synthetic method for benzoazoles has been successfully developed using water as the sole reaction medium in the absence of catalyst. The reaction was performed between ?-diketone derivatives and 2-aminothiophenols or 2-aminoanilines in water at 100 ?.14 benzoazoles were prepared with the highest yield up to 98%. The method can be used in the synthesis of 2-methyl benzimidazole and the product can be separated by filtering, the yield up to 92%.