Structural elucidation of unusual police exhibits. I: Dimethpramide ('Dimetcarb')

Abstract Yellow tablets, seized by police as intact blister packs, were subjected to molecular spectroscopic examination to elucidate the principal agent when they could not be identified by conventional ‘street drug’ screening. Structural information obtained from 1 H- and 13 C-NMR examination together with molecular weight and fragmentation characteristics obtained from mass spectrometry led to deduction of the simplest formula C 16 H 26 N 4 O 4 . This formula together with deduced knowledge of four substituent groups and their two probable arrangements on the benzene nucleus enabled the correct structure to be found and identified by searching in Chemical Abstracts. The substance, apparently known only in Russia and sold in tablet form as ‘Dimetcarb’ is otherwise known as dimethpramide or, more specifically, as N -[2-(diethylamino)ethyl]-4-(dimethylamino)-2-methoxy-5-nitrobenzamide.