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GC-MS and GC-IR Analyses of the Methoxy-1-n-pentyl-3-(1-naphthoyl)-indoles: Regioisomeric Designer Cannabinoids

NCJ Number
Journal of Chromatographic Science Volume: 56 Issue: 9 Dated: 2018 Pages: 779-788
Date Published
10 pages

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)

Date Published: January 1, 2018