title: GC-MS, MS/MS and GC-IR Analysis of a Series of Methylenedioxyphenyl-Aminoketones: Precursors, Ring Regioisomers and Side-Chain Homologs of 3,4-Methylenedioxypyrovalerone.
abstract: A combination of GC-MS, MS/MS and GC-IR techniques were used to characterize the ring substitution pattern, the alkyl side-chain and the cyclic tertiary amine portions of a series of six homologous and regioisomeric methylenedioxyphenyl-aminoketones related to the designer drug, 3,4-methylenedioxypyrovalerone (MDPV). Chromatographic retention increases with the hydrocarbon content of the alkyl side-chain and the 3,4-methylenedioxy substitution pattern shows higher retention than the corresponding 2,3-methylenedioxy isomer. The aminoketones show major peaks in their mass spectra corresponding to the homologous series of iminium cation fragments from the loss of the regioisomeric methylenedioxybenzoyl radical species. Deuterium labeling experiments confirm the iminium cation base peaks to undergo the loss of a hydrocarbon molecular fragment to yield product ions characteristic of the side-chain and pyrrolidine ring portion of the parent cathinone derivative. The mass spectra for the designer drug MDPV and its regioisomeric 2,3-methylenedioxy isomer show equivalent fragments including the base peak at m/z 126 and major product ion fragments at m/z 84. The ring substitution pattern for these two isomers was differentiated by characteristic absorption bands in the 1,500 -1,200 cm-1range in their vapor phase IR. These characteristic bands can also be used to identify the aromatic ring substitution pattern in the regioisomeric precursor ketones.
authors.affiliation: 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, Elbeida, Libya.
authors.forename: Younis F Hamad
authors.initials: YF
authors.lastname: Abiedalla
authors.affiliation: 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.
authors.forename: Karim
authors.initials: K
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 clarkcr@auburn.edu.
authors.forename: C Randall
authors.initials: CR
authors.lastname: Clark
mesh_terms: D052117:Benzodioxoles / Q000032:analysis / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D007659:Ketones / Q000032:analysis / Q000737:chemistry*; D011759:Pyrrolidines / Q000032:analysis / Q000737:chemistry*; D013237:Stereoisomerism; D053719:Tandem Mass Spectrometry / Q000379:methods*; D000094982:Synthetic Cathinone
chemical_list: D052117:Benzodioxoles; D007659:Ketones; D011759:Pyrrolidines; D000094982:Synthetic Cathinone