Tetrahedron

Ambident heterocyclic reactivity: Intramolecular alkylations of 2, 4-disubstituted benzimidazoles

MR Haque, M Rasmussen

文献索引：Haque, M. Rezaul; Rasmussen, Malcolm Tetrahedron, 1997 , vol. 53, # 20 p. 6937 - 6958

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被引用次数: 8

摘要

Alkali induced intramolecular cyclizations of 2-(3-chloropropyl)-and 2-(4-chlorobutyl)-4- substituted benzimidazoles bearing 4-nitro-, 4-amino-, and 4-methyl groups show enhanced N 3 N 1 regioselectivity compared to the corresponding intermolecular alkylations with 1- chlorobutane. The observed N1: N3 cyclization ratios vary from 94: 6 to 10: 90, with the largest preference for reaction at the 'congested'N3-site occurring in the 5-membered ring ...