A Novel Rearrangement in the System 3-[Aryl(chloro)methyl]quinoxalin-2(1H)-one—α-Picoline as a Simple and Efficient Route to Indolizin-2-ylbenzimidazoles.

A reaction of 3-(α-chlorobenzyl)quinoxalin-2(1 H)-one with α-picoline gives 2-(3-phenyl-indolizin-2-yl)benzimidazole as a result of a ring-contracting rearrangement involving the fragment C(2)—C(3)—C(Cl)Ph of the quinoxaline system and the fragment N=CH—Me of the α-picoline system. Possible pathways of this reaction are discussed.