A facile phase-transfer catalysed N-methylation of 2-substituted benzimidazoles

Citation
Pk. Dubey et al., A facile phase-transfer catalysed N-methylation of 2-substituted benzimidazoles, I J CHEM B, 39(11), 2000, pp. 867-871
Citations number
14
Categorie Soggetti
Organic Chemistry/Polymer Science
Journal title
INDIAN JOURNAL OF CHEMISTRY SECTION B-ORGANIC CHEMISTRY INCLUDING MEDICINAL CHEMISTRY
ISSN journal
03764699 → ACNP
Volume
39
Issue
11
Year of publication
2000
Pages
867 - 871
Database
ISI
SICI code
0376-4699(200011)39:11<867:AFPCNO>2.0.ZU;2-M
Abstract
N-Alkyl-2-acetylbenzimidazoles have been obtained by alkylating 2-acetylben zimidazole in CH3CN at RT for 30 min in over 90 yield using triethylbenzyla mmonium chloride as phase-transfer catalyst and anhyd. K2CO3 as base. When the same conditions are used to methylate simple 2-alkylbenzimidazoles, poo rer results were obtained. Optimum conditions have been worked out for the methylation of simple 2-alkylbenzimidazoles by changing (a) the solvent, (b ) the phase-transfer catalyst, (c) the concentration of the phase-transfer catalyst and (d) the type of phase-transfer catalysis itself. Using the opt imised conditions, a number of 1-methyl-2-alkylbenzimidazoles have been syn thesised in a facile manner.