Gas Chromatographic-Mass Spectrometric and High-Performance Liquid Chromatographic Analyses of the Bromination Products of the Regioisomeric Dimethoxyphenethylamines: Differentiation of Nexus from Five Positional Isomers

Abstract

The brominated products from all six positional isomers of dimethoxyphenethylamine are prepared, and their analytical properties are evaluated. The major bromination product from 3,5-dimethoxyphenethylamine is the 2,6-dibromo isomer; all other regioisomers of dimethoxyphenethylamine yield a monobromo species as the major product. The mass spectra divide these compounds into two distinct groups: one group showing a strong m/z 180 ion via loss of bromine from the molecular ion (M-Br)+ and a second group showing no significant m/z 180 ion. The three compounds that do not show the m/z 180 ion in their electron-impact mass spectra are brominated 2,4-; 2,5-; and 2,6-dimethoxyphenethylamine. These compounds are well-resolved by reversed-phase liquid chromatographic methods using a Hypersil Elite C18 stationary phase and a mobile phase of phosphate buffer (pH 3) and methanol-acetonitrile.