17625-81-9Relevant academic research and scientific papers
Synthesis of Asymmetrically Substituted Aminohalogenobenzimidazoles
Camarasa, Maria-Jose,Coe, Paul L.,Jones, A. Stanley,Walker, Richard T.
, p. 2317 - 2320 (2007/10/02)
2-Fluoroacetanilide (1) upon treatment with HNO3-H2SO4 at -5 to 0 deg C gave 6-fluoro-4-nitroacetanilide (3) whereas at -20 to -10 deg C the product was 6-fluoro-3,4-dinitroacetanilide (5).Although the formation of compound (5) could be accounted for by a conventional nitration mechanism, the fact that (3) could not be nitrated to give (5) and that (5) was formed at a lower temperature than was (3) suggested that the reaction might proceed via an ipso δ intermediate (2).Deacetylation of (5) followed by reduction and condensation with formic acid in the presence of HCl gave 6(5)-fluoro-5(6)-formylaminobenzimidazole (11), 5(6)-amino-6(5)-fluorobenzimidazole (12) and 5-amino-4-chloro-6-fluorobenzimidazole (13).Reduction of (5) with tin followed by condensation with acetic acid gave 5(6)-amino-6(5)-fluoro-2-methylbenzimidazole (14).Concomitant reduction and cyclisation of 6-chloro-2,4-dinitroaniline with formic acid and HCl gave a mixture of 7(4)-chloro-5(6)-formylaminobenzimidazole (15) and 5-amino-4,7-dichlorobenzimidazole (16).
