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- (n-propy1)-1 H-imidazole-4, 5-dicarbonitrile (96% yield) which was then hydrolyzed under ...
