New 3-(2'-Benzimidazolyl)imidazopyridinium Mesomeric Betaines. Synthesis and Structure

Article abstract of DOI:10.1021/jo00074a033

Reaction of N-<(2'-benzimidazolyl)methyl>pyridinium salts 2 with isothiocyanates results in a series of 3-(2'-benzimidazolyl)imidazo<1,2-a>pyridinium 2-thiolate derivatives 3 classified as conjugated mesomeric betaines.S-Methylation followed by deprotonation easily converts 3 into a new family of conjugated betaines 5.Semiempirical molecular orbital calculations provide complementary information to the X-ray analysis and experimental dipole moments of both betaines.