56653-44-2Relevant articles and documents
One-pot synthesis of 2-(1-alkyl/aralkyl-1H-benzimidazole-2-yl)-quinoxaline derivatives using molecular iodine
Dubey,Reddy, P. V. V. Prasada,Srinivas
, p. 613 - 618 (2008)
The title compound (5) has been prepared in one pot by refluxing 1-(1-alkyl/aralkyl-1H-benzimidazole-2-yl)-ethanone (1) with substituted o-phenylenediamine (2) in ethanol in the presence of iodine. Alternatively, 5 could also be prepared by treating 2-bromo-1-(1- alkyl/aralkyl-1H-benzimidazole- 2-yl)-ethanone (3A) with 2 in refluxing ethanol. The formation of 5 from 1 and 2 probably occurs through the intermediacy of 3B (i.e., 3, X=I) and 4. Copyright Taylor & Francis Group, LLC.
An unusual resistance to α-bromination by arylacetyl compound: Studies on bromination of 2-acetylbenzimidazoles and their subsequent reactions with sulphur nucleophiles - Synthesis of novel β-ketosulphone derivatives of benzimidazoles
Ramaiah,Dubey,Ramanatham,Grossert,Hooper
, p. 302 - 307 (2007/10/03)
Condensation of o-phenylenediamine with lactic acid under Phillips' conditions gave the known 2(α-hydroxyethyl)benzimidazole 1 which on oxidation with acid dichromate furnishes 2-acetylbenzimidazole 2. Reaction of 2 with bromine in acetic acid at room temp. give a novel product 3 but not the expected 2-(α-bromoacetyl)benzimidazole 4. Rational explanation is offered for this anamolous behaviour of 2. Compound 2 on alkylation, give 1- alkyl derivatives which undergo smooth bromination with bromine in acetic acid to give the corresponding 1-alkyl-2(α-bromoacetyl)benzimidazoles. Reactions of latter with sulphur nucleophiles such as PhS-, ArSO2- etc., resulting in substitution of bromine, leading to novel β-ketosulphone derivatives of benzimidazoles, are reported. Products have been characterised by IR, NMR (1H and 13C) and mass spectral data.
