Mukaiyama reagents in the synthesis of (E)-2-(1H-benzo[d]imidazol-2-yl)-2-[1-alkylpyridin-2(1H)ylidene]acetonitriles and their further electronic rearrangements effected by the action of acids and alkylating agents

Reactions of N-alkyl-2-chloropyridinium salts with benzimidazolylacetonitriles result in (E)-2-(1Hbenzod]imidazol-2-yl)-2-1-alkylpyridin-2(1H)-ylidene]acetonitriles. The alkylation of the latter with ω-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-benzod]-imidazol-2(3H)-ylidene(cyano)methyl)-1-methylpyridinium bromide due to the dearoylmethylation. The structure of the latter was proved by the XRD analysis.