Mukaiyama Reagents in the Synthesis of (^)-2-(1^-Benzo[^]imidazol-2-yl)-2-[1-alkylpyridin-2(1^)-ylidene]acetonitriles and Their Further Electronic Rearrangements Effected by the Action of Acids and Alkylating Agents.

Abstract

Reactions of N-alkyl-2-chloropyridinium salts with benzimidazolylacetonitriles result in (£)-2-(1Я-benzo[^imidazol-2-yl)-2-[1-alkylpyridin-2(1H)-ylidene]acetonitriles. The alkylation of the latter with co-bromoacetophenones in boiling acetone may gives rise to the N-alkylated salts, which are stabilized in two configurations, Z and E. The heating of the salts in acetonitrile causes their transformation into 2-({1H-benzo[d]-imidazol-2(3H)-ylidene}(cyano)methyl)-1-methylpyridinium bromide due to the dearoylmethylation. The structure of the latter was proved by the XRD analysis.