Premium
Novel synthesis of pyrido[1,2‐ a ]benzimidazoles via reaction of N ‐acyl arylhydroxylamines with pyridine
Author(s) -
Anderson David J.,
Taylor Arlen J.
Publication year - 1986
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570230426
Subject(s) - chemistry , benzimidazole , pyridine , medicinal chemistry , diamine , catalysis , stereochemistry , combinatorial chemistry , organic chemistry
The reduction of 4‐chloro‐3,5‐dinitrobenzonitrile via catalytic hydrogenation and/or titanium trichloride produced three successive hydroxylamines 6,7 , and 8 that were fully characterized during complete reduction to the diamine 9. The nitrohydroxylamine 6 was acetylated to the mono‐N ‐acetyl and bis ‐acetyl derivatives 10 and 11 which reacted with pyridine to afford the pyrido[1,2‐ a ]benzimidazole 13 . An analoguous series of reactions was executed with 4‐chloro‐3,5‐dinitrobenzotrifluoride to afford the pyrido[1,2‐ a ]benzimidazole 21 . Structure confirmation of 21 was established via an x‐ray determination. The mechanism of the transformation is discussed.