Correlation of vapor phase infrared spectra and regioisomeric structure in synthetic cannabinoids
| Autor: | Lewis W. Smith, C. Randall Clark, Younis Abiedalla, Amber Thaxton-Weissenfluh, Jack DeRuiter, Forrest Smith |
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| Rok vydání: | 2018 |
| Předmět: |
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Molecular Indoles Spectrophotometry Infrared Substituent Infrared spectroscopy Ring (chemistry) 01 natural sciences Designer Drugs Analytical Chemistry 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Structural isomer Moiety 030216 legal & forensic medicine Benzene Instrumentation Spectroscopy Pyrrole Indole test Cannabinoids Chemistry 010401 analytical chemistry Stereoisomerism Atomic and Molecular Physics and Optics 0104 chemical sciences Crystallography Gases |
| Zdroj: | Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. 196:375-384 |
| ISSN: | 1386-1425 |
| DOI: | 10.1016/j.saa.2018.02.052 |
| Popis: | The twelve 1-n-pentyl-2-, 3-, 4-, 5-, 6- and 7-(1- and 2-naphthoyl)-indoles each have the same substituents attached to the indole ring, identical elemental composition (C24H23NO) yielding identical nominal and accurate masses. These twelve isomers cover all possible positions of carbonyl bridge substitution for both indole (positons 2–7) and naphthalene rings (positions 1 and 2). Regioisomeric compounds can represent significant challenges for mass based analytical methods however, infrared spectroscopy is a powerful tool for the identification of positional isomers in organic compounds. The vapor phase infrared spectra of these twelve uniquely similar compounds were evaluated in GC-IR experiments. These spectra show the bridge position on the indole ring is a dominating influence over the carbonyl absorption frequency observed for these compounds. Substitution on the pyrrole moiety of the indole ring yields the lowest C O frequency values for position 2 and 3 giving a narrow range from 1656 to 1654 cm−1. Carbonyl absorption frequencies are higher when the naphthoyl group is attached to the benzene portion of the indole ring yielding absorption values from 1674 to 1671 cm−1. The aliphatic stretching bands in the 2900 cm−1 region yield a consistent triplet pattern because the N-alkyl substituent tail group remains unchanged for all twelve regioisomers. The asymmetric CH2 stretch is the most intense of these three bands. Changes in positional bonding for both the indole and naphthalene ring systems results in unique patterns within the 700 wavenumber out-of-plane region and these absorption bands are different for all 12 regioisomers. |
| Databáze: | OpenAIRE |
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