Mass Spectral, Infrared and Chromatographic Studies on Homologs and Regioisomers of 3,4-Methylenedioxypyrovalerone (MDPV)

Abstract

A series of 10 homologous and regioisomeric aminoketones related to the designer synthetic cathinone derivative MDPV were synthesized. These compounds were all prepared from a common precursor chemical, piperonal (3,4 methylenedioxybenzaldehyde). The analytical properties of these compounds were compared by GC-MS and GC-IR techniques. These aminoketones show major fragments in their mass spectra corresponding to the regioisomeric and homologous immonium cation fragments. All these compounds in this study show equivalent EI MS fragments for the 3,4-methylenedioxybenzoyl fragments (m/z 149) and the methylenedioxybenzene fragment )m/z 121). The vapor phase infrared spectra allow for the differentiation of the regioisomers of mass spectral equivalence.

The regioisomeric aminoketones yield equivalent mass spectra including mass equivalent regioisomeric immonium cation base peak which is identical to that of the designer drug MDPV. An evaluation of the effects of homologation on gas chromatographic retention showed that addition of a methylene (CH2) in the nitrogen-containing ring increases retention more than the equivalent group added to the alkyl side-chain.