Benzimidazole condensed ring systems. 2. New synthesis of substituted 1??oxo??1H, 5H??pyrido [1, 2??a] benzimidazole??4??carbonitriles and related derivatives

…, FSG Soliman, ESAM Badawey…

Index: Rida; Soliman; Badawey; Kappe Journal of Heterocyclic Chemistry, 1988 , vol. 25, # 6 p. 1725 - 1728

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Citation Number: 32

Abstract

Abstract The synthesis of some 3-substituted and 2, 3-disubstituted-1-oxo-1H, 5H-pyrido [1, 2-a] benzimidazole-4-carbo-nitriles 5, 6 by fusing 1H-benzimidazole-2-acetonitrile 1 with some β-keto esters 2, 4 in the presence of ammonium acetate or with ethyl β-aminocrotonate 3 is described. The tricyclic compounds were converted to their N-5 methyl of N-5 ethyl derivatives 8, 9. Vilsmeir-Haack formylation of 3-methyl-1-oxo-1H, 5H-pyrido [1, 2-a]- ...