Study On The Synthesis Of Novel Benzoimidazoles And Indenones

This paper consists of two parts. In the first part, we gave a novel way to synthesizea series of new benzoimidazoles.Benzoimidazole has been found a wide range of applications not only inagrochemical, biological and pharmacological fields, but also in polymer and dyestuffs.This part focused on the reaction of o-phenylenediamine with ketone. We found thatwhen those ketone substituted with electron-withdrawing groups, such as 1,3-dichloroacetone, 1,3-dihydroxyacetone and 1,3-dimethoxyacetone, the reaction couldefficiently proceed in a solvent and catalyst free conditions at ambient temperature,which helped explore an eff icient and green method to synthesize new benzoimidazoles.In the second part, we studied the synthesis of new indenones.Here we initated a comprehensive study on the reaction of propynone withdimethyl phosphonate and diphenylphosphane oxide promoted by Mn(OAc)₃·2H₂O.And the result presented us an addition and cyclization mechanism in the correspondingreactions under the promotion of Mn(OAc)₃·2H₂O to efficiently yield the expectedbioactive indenones. The typical mechanism of this reaction includes a selective attackon theα-position of propynone and then a follwing attack happened between the newradical in-situ and the benzene skeleton with formation of indenone as the ultimateproduct. It is the first example of tandem reaction to give phosphonyl radical promotedby manganese (III) acetate which regioselectively attacked propynone to yield novelindenones.