Sydnones as Masked Hydrazines for Heterocycle Formation: Reactions of 3-(2-Substituted Phenyl)sydnones with HCl

Article abstract of DOI:10.1002/hlca.19920750619

In general, reaction of 3-(2-substituted phenyl)sydnones with HCl gives products derived from cleavage of the sydnone ring to the corresponding hydrazine and subsequent cyclization to the side chain.In one case, 3-(2-aminophenyl)sydnone (43), the product obtained, 1-amino-1H-benzimidazole (47), apparently results from nucleophilic interception by the side chain prior to complete cleavage of the sydnone ring.