Heterocyclic carbanions. Synthesis of 2-substituted imidazole and benzimidazoles and of 3-substituted pyrazoles by lithiation of N-(dialkylamino) methyl heterocycles

AR Katritzky, GW Rewcastle…

Index: Katritzky, Alan R.; Rewcastle, Gordon W.; Fan, Wei-Qiang Journal of Organic Chemistry, 1988 , vol. 53, # 24 p. 5685 - 5689

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Citation Number: 46

Abstract

The lithiation of N-(dialky1amino) methyl (aminal) derivatives of imidazole, benzimidazole, and pyrazole (themselves readily available from the parent heterocycles, formaldehyde, and a secondary amine) occurs smoothly at the 2-, 2-, and 5-positions, respectively, upon treatment with n-butyllithium in ether or tetrahydrofuran. Reaction with electrophiles, and subsequent facile acid-catalyzed hydrolysis of the protecting group, provides 2-substituted ...