- A New Facile Sulfenylation of 2-Acetylbenzimidazoles
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A facile sulfenylation of 2-acetylbenzimidazoles has been achieved by using N-(phenylthio)phthalimide in the presence of potassium tert-butoxide in DMSO. The latter gave N-alkyl-β-phenylsulfenyl-2-acetylbenzimidazole on reaction with alkylating agents in the presence of potassium carbonate in N,N-dimethylformamide.
- Kumar, P. Praveen,Dathu Reddy,Ramana Reddy, Ch. Venkata,Rama Devi,Dubey
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- 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
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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.
- Ramaiah,Dubey,Ramanatham,Grossert,Hooper
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p. 302 - 307
(2007/10/03)
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