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Abiedalla Y, Clark CR. Electron ionization fragmentation studies for a series of 4-methoxymethylene benzoate esters. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2023; 37:e9654. [PMID: 37953540 DOI: 10.1002/rcm.9654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 09/29/2023] [Accepted: 10/02/2023] [Indexed: 11/14/2023]
Abstract
RATIONALE Product ion studies and stable isotope deuterium labeling experiments provide useful data for understanding the electron ionization (EI)-mass spectroscopy (MS) fragmentation of methoxymethylene substituted benzoate esters. The methoxymethylene ether is regioisomeric with the ethoxy group and represents the two possible ether substituents of a benzene ring of C2 H5 O. Structural confirmation of these synthetic precursor materials via gas chromatography (GC)-EI-MS revealed unexpected fragment ions. The synthesis and EI-MS evaluation of some homologs and deuterated derivatives allowed for the characterization of these unique ions and their fragmentation pathways. The relative effects of the position of the oxygen of the ether side chain are the subject of this investigation. METHODS The desired compounds were prepared from 4-chloromethylbenzoyl chloride by alkoxide displacement followed by transesterifications and the deuterated analogs were prepared similarly. The compounds were separated by capillary GC and their MS fragmentation evaluated in EI, MS/MS and chemical ionization experiments. RESULTS The methoxymethylene-substituted benzoate esters yield major fragment ions from the loss of the alkyl group from the ether as well as alkoxy group loss from the ester or ether portion of the molecule. The loss of the alkyl group from the ether followed by loss of the ester alkoxy group as the corresponding alcohol yielded the unique cation at m/z 133 for all compounds. The identity of the major ions was confirmed by product ion and deuterium labeling studies and possible mechanisms of fragment ion formation are described. CONCLUSIONS The aliphatic oxygen of the alkoxymethylene group plays a much more active role in the EI-MS fragment formation profile than the direct aromatic ring linked oxygen of the ethoxy group. Thus, yielding a greater variety of characteristic fragments. The m/z 133 ion is unique to this class of compounds and does not have an equivalent pathway for the regioisomeric ethoxy series.
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Affiliation(s)
- Younis Abiedalla
- Department of Drug Discovery and Development, Harrison College of Pharmacy, Auburn University, Auburn, Alabama, USA
- Department of Medicinal Chemistry, Faculty of Pharmacy, Omar Al-Mukhtar University, El-Beida, Al Bayda', Libya
| | - C Randall Clark
- Department of Drug Discovery and Development, Harrison College of Pharmacy, Auburn University, Auburn, Alabama, USA
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2
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Abdel-Hay KM, Belal TS, Abiedalla Y, Thaxton-Weissenfluh A, DeRuiter J, Smith F, Clark CR. Gas Chromatography-Mass Spectrometry (GC-MS) and Gas Chromatography-Infrared (GC-IR) Analyses of the Chloro-1- n-pentyl-3-(1-naphthoyl)-Indoles: Regioisomeric Cannabinoids. APPLIED SPECTROSCOPY 2019; 73:433-443. [PMID: 30347999 DOI: 10.1177/0003702818809998] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The analytical differentiation of the indole ring regioisomeric chloro-1- n-pentyl-3-(1-naphthoyl)-indoles is described in this report. The regioisomeric chloroindole precursor compounds, N- n-pentyl chloroindole synthetic intermediates, and the target chloro-substituted naphthoylindoles showed the equivalent gas chromatographic elution order based on the position of chlorine substitution on the indole ring. The regioisomeric chloro-1- n-pentyl-3-(1-naphthoyl)-indoles yield electron ionization mass spectra having equivalent major fragments resulting from cleavage of the groups attached to the central indole nucleus. Fragment ions occur at m/z 127 and 155 for the naphthyl and naphthoyl cations common to all indoles having the naphthoyl group substituted at the indole-3 position. Fragments resulting from the loss of the naphthoyl and/or n-pentyl groups from the molecular radical cation yield the cations at m/z 318, 304, 248, and 178. The characteristic (M-17)+ fragment ion at m/z 358 resulting from the loss of OH radical is significant in the mass spectra of all these compounds with 1-naphthoyl groups substituted at the indole-3 position. The vapor phase infrared spectra provide a number of characteristic absorption bands to identify the individual isomers.
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Affiliation(s)
- Karim M Abdel-Hay
- 1 Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL, USA
- 2 Department of Chemistry, College of Science, Eastern Kentucky University, Richmond, KY, USA
- 3 Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Tarek S Belal
- 3 Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Younis Abiedalla
- 1 Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL, USA
- 4 Department of Medicinal Chemistry, Faculty of Pharmacy, Omar Al-Mukhtar University, El-Beida, Libya
| | - Amber Thaxton-Weissenfluh
- 1 Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL, USA
| | - Jack DeRuiter
- 1 Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL, USA
| | - Forrest Smith
- 1 Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL, USA
| | - C Randall Clark
- 1 Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL, USA
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3
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Spectroscopic differentiation and chromatographic separation of regioisomeric indole aldehydes: Synthetic cannabinoids precursors. Forensic Chem 2019. [DOI: 10.1016/j.forc.2018.12.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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4
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Thaxton-Weissenfluh A, Belal TS, DeRuiter J, Smith F, Abiedalla Y, Neel L, Abdel-Hay KM, Clark CR. GC-MS and GC-IR Analyses of the Methoxy-1-n-pentyl-3-(1-naphthoyl)-indoles: Regioisomeric Designer Cannabinoids. J Chromatogr Sci 2018; 56:779-788. [PMID: 29920587 DOI: 10.1093/chromsci/bmy059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 05/23/2018] [Indexed: 11/13/2022]
Abstract
The indole ring regioisomeric methoxy-1-n-pentyl-3-(1-naphthoyl)-indoles represent indole ring-substituted analogs of the synthetic cannabinoid JWH-018. The electron ionization mass spectra show 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 a number of 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.
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Affiliation(s)
- Amber Thaxton-Weissenfluh
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL, USA
| | - Tarek S Belal
- Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Jack DeRuiter
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL, USA
| | - Forrest Smith
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL, USA
| | - Younis Abiedalla
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL, USA.,Department of Medicinal Chemistry, Faculty of Pharmacy, Omar Al-Mukhtar University, El-Beida, Libya
| | - Logan Neel
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL, USA
| | - Karim M Abdel-Hay
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL, USA.,Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - C Randall Clark
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL, USA
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5
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Chikumoto T, Furukawa R, Kohyama E, Suenami K, Nagai H, Tada H, Kawashima H, Kadomura N, Soda M, Kitaichi K, Ito T. Liquid chromatography–mass spectrometry studies on the isomeric 1-fluorobenzyl-3-naphthoyl-indoles: FUB-JWH-018 and five isomers. Forensic Toxicol 2018. [DOI: 10.1007/s11419-018-0442-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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6
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Belal TS, Thaxton-Weissenfluh A, DeRuiter J, Smith F, Abiedalla Y, Abdel-Hay KM, Clark CR. Differentiation of methylated indole ring regioisomers of JWH-007: GC–MS and GC–IR studies. Forensic Chem 2018. [DOI: 10.1016/j.forc.2017.11.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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7
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Thaxton-Weissenfluh A, Alsegiani AS, Abiedalla Y, DeRuiter J, Smith F, Clark CR. Analytical studies on the 2-naphthoyl substituted-1-n-pentylindoles: Regioisomeric synthetic cannabinoids. J Chromatogr B Analyt Technol Biomed Life Sci 2018; 1077-1078:77-84. [PMID: 29413581 DOI: 10.1016/j.jchromb.2018.01.036] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 01/23/2018] [Accepted: 01/27/2018] [Indexed: 11/29/2022]
Abstract
The six 1-n-pentyl-2-, 3-, 4-, 5-, 6- and 7-(2-naphthoyl)-indoles each have the same substituents attached to the indole ring, identical elemental composition (C24H23NO) yielding identical nominal and accurate masses. The electron ionization mass spectra of the 2-naphthoyl substituted isomers share equivalent major fragment ions resulting from cleavage of the groups attached to the central indole nucleus with some differences in relative abundances. These six regioisomers were successfully resolved on an Rtx-5 and Rxi-17Sil MS stationary phases and the molecules having both substituent groups on the same side of the indole ring (1,2- and 1,7-substituents) show the least retention. The more linear molecules have higher relative retention properties. A comparison of the GC properties of the 1-naphthoyl- and 2-naphthoyl groups attached at identical positions of the indole ring showed higher GC retention for the 2-naphthoyl substituted isomer in all cases evaluated. The amide inverse isomers (1-naphthoyl-3-n-pentylindoles) were separated from the 1-n-pentyl-3-naphthoyl-indoles on an Rtx-200 stationary phase. The two inverse amide isomers having the 1- and 2-naphthoyl groups substituted at the 1-position of the indole ring elute before either of the N-alkyl-indole isomers having the 1- and 2-naphthoyl groups substituted at the 3-position of the indole ring. The amide inverse isomers yield EI mass spectra easily distinguishing these amides from the ketone isomers having the naphthoyl groups at the indole 3-position.
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Affiliation(s)
- Amber Thaxton-Weissenfluh
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL 36849, USA
| | - Amsha S Alsegiani
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL 36849, USA
| | - Younis Abiedalla
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL 36849, USA; Department of Medicinal Chemistry, Faculty of Pharmacy, Omar Al-Mukhtar University, El-Beida, Libya
| | - Jack DeRuiter
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL 36849, USA
| | - Forrest Smith
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL 36849, USA
| | - C Randall Clark
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL 36849, USA.
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8
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Regioisomeric differentiation of synthetic cannabinoids with an N-fluorobenzyl indole core by gas chromatography–tandem mass spectrometry. Forensic Chem 2017. [DOI: 10.1016/j.forc.2017.09.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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9
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Kohyama E, Chikumoto T, Tada H, Kitaichi K, Ito T. Analytical differentiation of quinolinyl- and isoquinolinyl-substituted 1-(5-fluoropentyl)-1 H-indole-3-carboxylates: 5F-PB-22 and its ten isomers. Forensic Toxicol 2016; 35:56-65. [PMID: 28127408 PMCID: PMC5215287 DOI: 10.1007/s11419-016-0334-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 07/27/2016] [Indexed: 12/01/2022]
Abstract
Differentiation among regioisomers of synthetic cannabinoids in forensic drug analysis is a crucial issue, since all isomers are not regulated by law. New equivalent analogs obtained via minor modification of their preexisting molecules keep on emerging. Isomers formed via substitutional exchange are also a cause for concern. This study is focused on the isomeric molecules that stem from minor modifications of 5F-PB-22. The analytical properties of these molecules and methods of differentiation are reported. Scan mode analysis using gas chromatography-electron ionization-mass spectrometry (GC-EI-MS) was performed using the authentic 5F-PB-22 standard, five regioisomeric quinolinyl ester indoles, and five regioisomeric isoquinolinyl ester indoles. Because it was not possible to separate 5F-PB-22 from the 5-hydroxyquinoline isomer using GC and all analytes showed similar EI mass spectra, liquid chromatography (LC)-tandem mass spectrometry analysis was performed. Using LC, a successful separation of 5F-PB-22 from all isomers could be achieved. Based on the electrospray ionization-mass spectra, the protonated molecular ion at m/z 377.2 was selected as the precursor ion for the regioisomeric and structural isomeric differentiation. Collision-induced dissociation provides relative intensity differences in the product ions among the isomers, enabling mass spectrometric differentiation of the isomers. To our knowledge, this is the first report on mass spectrometric differentiation of 5F-PB-22 and its ten isomers.
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Affiliation(s)
- Erina Kohyama
- Gifu Prefectural Research Institute for Health and Environmental Sciences, 1-1 Naka-fudogaoka, Kakamigahara, Gifu, 504-0838 Japan
| | - Takao Chikumoto
- Gifu Prefectural Research Institute for Health and Environmental Sciences, 1-1 Naka-fudogaoka, Kakamigahara, Gifu, 504-0838 Japan
| | - Hiroyuki Tada
- Gifu Prefectural Research Institute for Health and Environmental Sciences, 1-1 Naka-fudogaoka, Kakamigahara, Gifu, 504-0838 Japan
| | - Kiyoyuki Kitaichi
- Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu, 501-1196 Japan
| | - Tetsuro Ito
- Gifu Prefectural Research Institute for Health and Environmental Sciences, 1-1 Naka-fudogaoka, Kakamigahara, Gifu, 504-0838 Japan ; Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu, 501-1196 Japan
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10
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Abdel-Hay KM, De Ruiter J, Smith F, Alsegiani AS, Thaxton-Weissenfluh A, Clark CR. GC–MS differentiation of the six regioisomeric dimethoxybenzoyl-1-pentylindoles: Isomeric cannabinoid substances. J Pharm Biomed Anal 2016; 125:360-8. [DOI: 10.1016/j.jpba.2016.04.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 04/07/2016] [Accepted: 04/10/2016] [Indexed: 11/27/2022]
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11
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Longworth M, Banister SD, Mack JBC, Glass M, Connor M, Kassiou M. The 2-alkyl-2 H-indazole regioisomers of synthetic cannabinoids AB-CHMINACA, AB-FUBINACA, AB-PINACA, and 5F-AB-PINACA are possible manufacturing impurities with cannabimimetic activities. Forensic Toxicol 2016; 34:286-303. [PMID: 27547266 PMCID: PMC4971050 DOI: 10.1007/s11419-016-0316-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 04/01/2016] [Indexed: 01/14/2023]
Abstract
Indazole-derived synthetic cannabinoids (SCs) featuring an alkyl substituent at the 1-position and l-valinamide at the 3-carboxamide position (e.g., AB-CHMINACA) have been identified by forensic chemists around the world, and are associated with serious adverse health effects. Regioisomerism is possible for indazole SCs, with the 2-alkyl-2H-indazole regioisomer of AB-CHMINACA recently identified in SC products in Japan. It is unknown whether this regiosiomer represents a manufacturing impurity arising as a synthetic byproduct, or was intentionally synthesized as a cannabimimetic agent. This study reports the synthesis, analytical characterization, and pharmacological evaluation of commonly encountered indazole SCs AB-CHMINACA, AB-FUBINACA, AB-PINACA, 5F-AB-PINACA and their corresponding 2-alkyl-2H-indazole regioisomers. Both regioisomers of each SC were prepared from a common precursor, and the physical properties, 1H and 13C nuclear magnetic resonance spectroscopy, gas chromatography-mass spectrometry, and ultraviolet-visible spectroscopy of all SC compounds are described. Additionally, AB-CHMINACA, AB-FUBINACA, AB-PINACA, and 5F-AB-PINACA were found to act as high potency agonists at CB1 (EC50 = 2.1-11.6 nM) and CB2 (EC50 = 5.6-21.1 nM) receptors in fluorometric assays, while the corresponding 2-alkyl-2H-indazole regioisomers demonstrated low potency (micromolar) agonist activities at both receptors. Taken together, these data suggest that 2-alkyl-2H-indazole regioisomers of AB-CHMINACA, AB-FUBINACA, AB-PINACA, and 5F-AB-PINACA are likely to be encountered by forensic chemists and toxicologists as the result of improper purification during the clandestine synthesis of 1-alkyl-1H-indazole regioisomers, and can be distinguished by differences in gas chromatography-mass spectrometry fragmentation pattern.
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Affiliation(s)
- Mitchell Longworth
- School of Chemistry, The University of Sydney, Sydney, NSW 2006 Australia
| | - Samuel D Banister
- School of Chemistry, The University of Sydney, Sydney, NSW 2006 Australia.,Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA USA
| | - James B C Mack
- Department of Chemistry, Stanford University, Stanford, CA USA
| | - Michelle Glass
- School of Medical Sciences, The University of Auckland, Auckland, New Zealand
| | - Mark Connor
- Department of Biomedical Sciences, Macquarie University, Sydney, Australia
| | - Michael Kassiou
- School of Chemistry, The University of Sydney, Sydney, NSW 2006 Australia.,Faculty of Health Sciences, The University of Sydney, Sydney, Australia
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12
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Diao X, Scheidweiler KB, Wohlfarth A, Zhu M, Pang S, Huestis MA. Strategies to distinguish new synthetic cannabinoid FUBIMINA (BIM-2201) intake from its isomer THJ-2201: metabolism of FUBIMINA in human hepatocytes. Forensic Toxicol 2016; 34:256-267. [PMID: 27547265 PMCID: PMC4971051 DOI: 10.1007/s11419-016-0312-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 03/09/2016] [Indexed: 12/26/2022]
Abstract
Since 2013, a new drugs-of-abuse trend attempts to bypass drug legislation by marketing isomers of scheduled synthetic cannabinoids (SCs), e.g., FUBIMINA (BIM-2201) and THJ-2201. It is much more challenging to confirm a specific isomer’s intake and distinguish it from its structural analog because the isomers and their major metabolites usually have identical molecular weights and display the same product ions. Here, we investigated isomers FUBIMINA and THJ-2201 and propose strategies to distinguish their consumption. THJ-2201 was scheduled in the US, Japan, and Europe; however, FUBIMINA is easily available on the Internet. We previously investigated THJ-2201 metabolism in human hepatocytes, but human FUBIMINA metabolism is unknown. We aim to characterize FUBIMINA metabolism in human hepatocytes, recommend optimal metabolites to confirm its consumption, and propose strategies to distinguish between intakes of FUBIMINA and THJ-2201. FUBIMINA (10 μM) was incubated in human hepatocytes for 3 h, and metabolites were characterized with high-resolution mass spectrometry (HR-MS). We identified 35 metabolites generated by oxidative defluorination, further carboxylation, hydroxylation, dihydrodiol formation, glucuronidation, and their combinations. We recommend 5′-OH-BIM-018 (M34), BIM-018 pentanoic acid (M33), and BIM-018 pentanoic acid dihydrodiol (M7) as FUBIMINA specific metabolites. THJ-2201 produced specific metabolite markers 5′-OH-THJ-018 (F26), THJ-018 pentanoic acid (F25), and hydroxylated THJ-2201 (F13). Optimized chromatographic conditions to achieve different retention times and careful selection of specific product ion spectra enabled differentiation of isomeric metabolites, in this case FUBIMINA from THJ-2201. Our HR-MS approach should be applicable for differentiating future isomeric SCs, which is especially important when different isomers have different legal status.
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Affiliation(s)
- Xingxing Diao
- Chemistry and Drug Metabolism, IRP, National Institute on Drug Abuse, National Institutes of Health, 251 Bayview Blvd, Suite 200 Room 05A721, Baltimore, MD 21224 USA
| | - Karl B. Scheidweiler
- Chemistry and Drug Metabolism, IRP, National Institute on Drug Abuse, National Institutes of Health, 251 Bayview Blvd, Suite 200 Room 05A721, Baltimore, MD 21224 USA
| | - Ariane Wohlfarth
- Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine, 58758 Linköping, Sweden
- Department of Drug Research, University of Linköping, 58185 Linköping, Sweden
| | - Mingshe Zhu
- Department of Biotransformation, Bristol-Myers Squibb, Research and Development, Princeton, NJ 08543 USA
| | | | - Marilyn A. Huestis
- Chemistry and Drug Metabolism, IRP, National Institute on Drug Abuse, National Institutes of Health, 251 Bayview Blvd, Suite 200 Room 05A721, Baltimore, MD 21224 USA
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13
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Thaxton A, Belal TS, Smith F, DeRuiter J, Abdel-Hay KM, Clark CR. Mass spectral studies on 1-n-pentyl-3-(1-naphthoyl)indole (JWH-018), three deuterium-labeled analogues and the inverse isomer 1-naphthoyl-3-n-pentylindole. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2015; 29:871-877. [PMID: 26377015 DOI: 10.1002/rcm.7171] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 01/23/2015] [Accepted: 02/13/2015] [Indexed: 06/05/2023]
Abstract
RATIONALE A number of synthetic cannabinoids such as the 1-alkyl-3-acylindoles are the target of significant designer drug activity. One of the first waves of these compounds identified in clandestine samples was 1-n-pentyl-3-(1-naphthoyl)indole, JWH-018. These totally synthetic molecules can be prepared in a number of regioisomeric forms. METHODS The electron ionization mass spectrometric (EI-MS) fragmentation of the 1-n-pentyl-3-(1-naphthoyl)indole is compared to its inverse isomer 1-naphthoyl-3-n-pentylindole. These two substances are directly available from indole using identical precursor reagents and similar reaction conditions. Stable isotope deuterium labeling of the three major regions of the JWH-018 molecule allows confirmation of the structures of the major fragment ions. The spectra for the 1-n-pentyl-3-(1-naphthoyl)-d(5) -indole, 1-n-pentyl-3-(1-d(7) -naphthoyl)indole and 1-d(11) -n-pentyl-3-(1-naphthoyl)indole provide significant assistance in elucidating the structures for the major fragment ions in JWH-018. RESULTS The EI mass spectra for these isomers show a number of unique ions which allow for the differentiation of the 1-alkyl-3-acylindole compounds from the inverse regioisomeric 1-acyl-3-alkylindoles. The fragment ion [M-17](+) at m/z 324 for JWH-018 was formed by the elimination of a hydroxyl radical and the spectra of the three deuterium-labeled derivatives indicated the loss of hydrogen from the naphthalene ring. Further structural analogues suggest the hydrogen to come from the 8-position of the naphthalene ring. CONCLUSIONS The three deuterium-labeled analogues provide significant assistance in confirming the structures for the major fragment ions in the mass spectrum of the traditional synthetic cannabinoid compound, 1-n-pentyl-3-(1-naphthoyl)indole, JWH-018. The 1-naphthoyl-3-n-pentylindole inverse regioisomer can be easily differentiated from the traditional synthetic cannabinoid compound.
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Affiliation(s)
- Amber Thaxton
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL, 36849, USA
| | - Tarek S Belal
- Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Alexandria University, Alexandria, 21521, Egypt
| | - Forrest Smith
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL, 36849, USA
| | - Jack DeRuiter
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL, 36849, USA
| | - Karim M Abdel-Hay
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL, 36849, USA
- Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Alexandria University, Alexandria, 21521, Egypt
| | - C Randall Clark
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL, 36849, USA
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14
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GC-MS studies on the six naphthoyl-substituted 1-n-pentyl-indoles: JWH-018 and five regioisomeric equivalents. Forensic Sci Int 2015; 252:107-13. [PMID: 25965306 DOI: 10.1016/j.forsciint.2015.04.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 04/07/2015] [Accepted: 04/20/2015] [Indexed: 11/24/2022]
Abstract
The GC-MS properties of the synthetic cannabinoid drug of abuse 3-(1-naphthoyl)-1-pentylindole (JWH-018) and all 5 of its' regioisomeric 1-naphthoyl substituted 1-n-pentylindoles are compared in this report. These compounds have the 1-naphthoyl-group attached at each of the possible substituent positions of the indole ring. The six compounds have the same elemental composition C24H23NO and the same substituents attached to the indole ring. The electron ionization mass spectra showed equivalent regioisomeric major fragment ions resulting from cleavage of the groups attached to the central indole nucleus. The characteristic (M-17)(+) fragment ion at m/z 324 resulting from the loss of an OH group was significant in the EI-MS of 3-, 4-, 5- and 6-(1-naphthoyl)-1-pentylindole. Fragment ions occurred at m/z 127 and 155 for the naphthyl and naphthoyl cations common to all six regioisomeric substances. Indole containing fragments produced the cations at m/z 284, 270, 214 and 186. The unique fragment at m/z 141 observed in the 1,2- and 1,7-isomers resulted from a rearrangement involving the two indole substituents to yield the C10H7CH2(+) cation. The major points of EI-MS differentiation of the synthetic cannabinoid JWH-018 from the other five isomers are the high relative abundance of both the m/z 144 ion and the m/z 324 ion in the JWH-018 spectrum. GC separations on a capillary column containing a trifluoropropyl methyl polysiloxane (Rtx-200) stationary phase provided excellent resolution of these six compounds. The elution order appears related to the relative distance between the two indole substituents with the lowest retention associated with minimum distance between the groups attached to the indole nucleus.
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15
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Abdel-Hay KM, DeRuiter J, Smith F, Belal TS, Clark CR. GC-MS analysis of the regioisomeric methoxy- and methyl-benzoyl-1-pentylindoles: Isomeric synthetic cannabinoids. Sci Justice 2015; 55:291-8. [PMID: 26385710 DOI: 10.1016/j.scijus.2015.02.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 02/20/2015] [Accepted: 02/26/2015] [Indexed: 11/30/2022]
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.
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Affiliation(s)
- Karim M Abdel-Hay
- 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
| | - Jack DeRuiter
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL 36849, USA
| | - Forrest Smith
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL 36849, USA
| | - Tarek S Belal
- Dept. of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Alexandria University, Alexandria 21521, Egypt
| | - C Randall Clark
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL 36849, USA.
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16
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Namera A, Kawamura M, Nakamoto A, Saito T, Nagao M. Comprehensive review of the detection methods for synthetic cannabinoids and cathinones. Forensic Toxicol 2015. [PMID: 26257831 DOI: 10.1007/211419-015-0270-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
A number of N-alkyl indole or indazole-3-carbonyl analogs, with modified chemical structures, are distributed throughout the world as synthetic cannabinoids. Like synthetic cannabinoids, cathinone analogs are also abused and cause serious problems worldwide. Acute deaths caused by overdoses of these drugs have been reported. Various analytical methods that can cope with the rapid changes in chemical structures are required for routine analysis and screening of these drugs in seized and biological materials for forensic and clinical purposes. Although many chromatographic methods to analyze each drug have been published, there are only a few articles summarizing these analytical methods. This review presents the various colorimetric detections, immunochemical assays, gas chromatographic-mass spectrometric methods, and liquid chromatographic-mass spectrometric methods proposed for the analysis of synthetic cannabinoids and cathinones.
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Affiliation(s)
- Akira Namera
- Department of Forensic Medicine, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553 Japan
| | - Maho Kawamura
- Forensic Science Laboratory, Hiroshima Prefectural Police Headquarters, Hiroshima, Japan
| | - Akihiro Nakamoto
- Forensic Science Laboratory, Hiroshima Prefectural Police Headquarters, Hiroshima, Japan
| | - Takeshi Saito
- Department of Emergency and Critical Care Medicine, Tokai University School of Medicine, Isehara, Japan
| | - Masataka Nagao
- Department of Forensic Medicine, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553 Japan
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17
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Namera A, Kawamura M, Nakamoto A, Saito T, Nagao M. Comprehensive review of the detection methods for synthetic cannabinoids and cathinones. Forensic Toxicol 2015; 33:175-194. [PMID: 26257831 PMCID: PMC4525208 DOI: 10.1007/s11419-015-0270-0] [Citation(s) in RCA: 133] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 01/29/2015] [Indexed: 12/26/2022]
Abstract
A number of N-alkyl indole or indazole-3-carbonyl analogs, with modified chemical structures, are distributed throughout the world as synthetic cannabinoids. Like synthetic cannabinoids, cathinone analogs are also abused and cause serious problems worldwide. Acute deaths caused by overdoses of these drugs have been reported. Various analytical methods that can cope with the rapid changes in chemical structures are required for routine analysis and screening of these drugs in seized and biological materials for forensic and clinical purposes. Although many chromatographic methods to analyze each drug have been published, there are only a few articles summarizing these analytical methods. This review presents the various colorimetric detections, immunochemical assays, gas chromatographic-mass spectrometric methods, and liquid chromatographic-mass spectrometric methods proposed for the analysis of synthetic cannabinoids and cathinones.
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Affiliation(s)
- Akira Namera
- Department of Forensic Medicine, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553 Japan
| | - Maho Kawamura
- Forensic Science Laboratory, Hiroshima Prefectural Police Headquarters, Hiroshima, Japan
| | - Akihiro Nakamoto
- Forensic Science Laboratory, Hiroshima Prefectural Police Headquarters, Hiroshima, Japan
| | - Takeshi Saito
- Department of Emergency and Critical Care Medicine, Tokai University School of Medicine, Isehara, Japan
| | - Masataka Nagao
- Department of Forensic Medicine, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553 Japan
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18
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Smith FT, DeRuiter J, Abdel-Hay K, Randall Clark C. GC–MS and FTIR evaluation of the six benzoyl-substituted-1-pentylindoles: Isomeric synthetic cannabinoids. Talanta 2014; 129:171-82. [DOI: 10.1016/j.talanta.2014.05.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 05/14/2014] [Accepted: 05/17/2014] [Indexed: 11/25/2022]
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