Diethyl 2-(n-propyl)1 H-imidazole-4,5-dicarboxylate (4) is an intermediate in the synthesis of olmesartan, a non-peptide angiotensin I1 receptor antagonist.'-2 Yanagisawa et reported using diaminomaleonitrile and trimethyl orthobutyrate as starting materials. Thus, diaminomaleonitrile was treated with trimethyl orthobutyrate in acetonitrile to provide the 2(npropy1)1 H-imidazole-4,5-dicarbonitrile (96% yield) which was then hydrolyzed under acidic conditions to afford 3 (80%). Esterification of 3 in ethanol in the presence of hydrogen chloride gave 4 in 86% yield (Scheme I). ... 111 ii HOOC

This study improved the synthesis of 2-n-(n-propyl)-1H-imidazole-4,5-dicarboxylic acid diethanol ester using diaminomaleonitrile and trimethyl orthobutyrate, leading to a more efficient intermediate in the synthesis of olmes

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AN IMPROVED SYNTHESIS OF 2-n-(PROPYL)-1H-IMIDAZOLE-4,5-DICARBOXYLIC ACID DIETHYL ESTER

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