Carbonylation of o-Phenylenediamine and o-Aminophenol with Dimethyl Carbonate using Lead Compounds as Catalysts

摘要

Lead compounds are active catalysts for carbonylation and carbonylation/methylation of o-phenylenediamine and o-aminophenol with dimethyl carbonate (DMC).2-Benzimidazolone was obtained in 84% yield by the reaction of o-phenylenediamine with DMC for 1 h at 443K in the presence of Pb(NO_3)_2.In the presence of Pb(OAc)_2,the reaction quantitatively gave 1,3-dimethyl-2-benzimidazolone,which was formed by methylation of the primary product,2-bezimidazolone,at 473K.The effects of reaction variables ont he yields of 2-benzimidazolone were examined.The reaction of o-aminophneol with DMC selectively gave a carbonylation product,3-methyl-2-benzoxazolone,depending on the reaction conditions in the presence of Pb(OAc)_2.