201749-03-3Relevant academic research and scientific papers
New Heterocyclization Reaction via the Opening of Benzimidazole Heterocycle: Formation of Pyrazoles in the Acylation of Arylhydrazones of (2-Benzimidazolylmethyl)ketones
Dzvinchuk,Vypirailenko,Lozinskii
, p. 103 - 107 (2007/10/03)
Heterocyclization that takes place upon the acylation of arylhydrazones of 2-acetonyl- and 2-phenacylbenzimidazoles via the opening of the benzimidazole ring to form 5-(o-acylaminophenyl)aminopyrazoles was studied. The transformation readily proceeds upon treatment with aroyl chlorides or acetic anhydride in pyridine. The heterocyclizalion is facilitated by substituents that increase the nucleophilicity of the sp3 -hybridized nitrogen atom of the hydrazone moiety and the electrophilicity of the acylating reagent. The arylhydrazones of 2-phenacylbenzimidazole produce pyrazoles more readily than the corresponding acetonyl derivatives do.
