This article reports on a project that involved the GC-MS and GC-IR analyses of the methoxy-1-n-pentyl-3-(1-naphthoyl)-indoles, which represent indole ring-substituted analogs of the synthetic cannabinoid JEH-018.
The electron ionization mass spectra showed equivalent regioisomeric major fragments resulting from cleavage of the groups attached to the central indole nucleus. The characteristic (M-17)+ fragment ion at m/z 354 resulting from the loss of OH group is significant in the mass spectra of all four compounds. Fragmentation of the naphthoyl and/or pentyl groups yields the cations at m/z 314, 300, 244 and 216. The vapor-phase infrared spectra provide some characteristic absorption bands to identify the individual isomers. Gas chromatographic separations on a capillary column containing a film of trifluoropropylmethyl polysiloxane (Rtx-200) provided excellent resolution of these compounds, their precursor indoles and intermediate pentylindoles. The elution order appears related to the degree of crowding of indole ring substituents. (publisher abstract modified)