Aromatization reaction of dihydrofuranones

Abstract

Dihydrobenzofuranones(2) were prepared from 2-alky carbonyl cyclohexanones(1) and butyl pyruvate in the presence of acid catalyst and N-benzyl dihydro-5-azabenzofuranones(5) were prepared from 3-alkyl carbonylbenzyl-4-piperidones(4) and butyl pyruvate in the presence of acid catalyst. The aromatization of dihydrobenzofuranones(2) in the presence of anhydrous pyridin hydrochloride yielded the corresponding acids(3). N-benzyl dihydro-5-azabezofuranones(5) were converted into N-carbomethoxy-5-azabenzofuranones(6). Contrast to dihydrobenzofuranones, the aromatization of 6 gave the corresponding 3-alkyl carbony15-ethyl pyridines(7). ##