title: GC-MS analysis of the regioisomeric methoxy- and methyl-benzoyl-1-pentylindoles: Isomeric synthetic cannabinoids.
abstract: The regioisomeric 1-n-pentyl-3-(methoxybenzoyl)indoles and the 1-n-pentyl-3-(methylbenzoyl)indoles represent potential designer modifications in the synthetic cannabinoid drug category. These six compounds were prepared by a two-step synthetic method. The analytical properties and methods of regioisomeric differentiation were developed in this study. The molecular ion represents the base peak in the EI mass spectra for most of the compounds in this group. The meta- and para-isomers in each series display fragment ions at equivalent masses with some differences in relative abundance of these ions. The ortho-substituted isomers for both the methoxybenzoyl and methylbenzoyl series show a unique fragment ion occurring at M-17. Deuterium labeling for the methoxy group in the ortho-methoxybenzoyl isomer (ortho-OCD3) confirmed the ortho-substituent as the source of the hydrogen in OH (M-17) elimination. The two sets of regioisomers were well resolved by capillary gas chromatography and the elution order reflected increasing molecular linearity. In both sets of compounds the ortho-isomer eluted first and the para-isomer showed the highest retention time. The HPLC separation showed the ortho-isomer eluting first and the meta-isomer eluting last in both sets of regioisomers.
authors.affiliation: Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL 36849, USA; Dept. of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Alexandria University, Alexandria 21521, Egypt.
authors.forename: Karim M
authors.initials: KM
authors.lastname: Abdel-Hay
authors.affiliation: Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL 36849, USA.
authors.forename: Jack
authors.initials: J
authors.lastname: DeRuiter
authors.affiliation: Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL 36849, USA.
authors.forename: Forrest
authors.initials: F
authors.lastname: Smith
authors.affiliation: Dept. of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Alexandria University, Alexandria 21521, Egypt.
authors.forename: Tarek S
authors.initials: TS
authors.lastname: Belal
authors.affiliation: Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL 36849, USA. Electronic address: clarkcr@auburn.edu.
authors.forename: C Randall
authors.initials: CR
authors.lastname: Clark
mesh_terms: D002186:Cannabinoids / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007536:Isomerism; D015394:Molecular Structure
chemical_list: D002186:Cannabinoids
keywords: Forensic chemistry; GC–MS; Indole derivatives; Regioisomers; Synthetic cannabinoids