Characterization of (2R,4S)- and (2R,4R)-2-Methylfentanyl and their differentiation from cis- and trans-3-Methylfentanyl

United Nations Office on Drugs and Crime (UNODC). Global Smart Update. Fentanyl and its analogues – 50 years on. Available at: http://www.unodc.org/documents/scientific/Global_SMART_Update_Vol.17_web.pdf. Accessed November 8, 2017. Noble, 2017, Application of a screening method for fentanyl and its analogues using UHPLC-QTOF-MS with data-independent acquisition (DIA) in MSE mode and retrospective analysis of authentic forensic blood samples, Drug Test. Anal. Vardanyan, 2014, Fentanyl-related compounds and derivatives: Current status and future prospects for pharmaceutical applications, Future Med. Chem., 6, 385, 10.4155/fmc.13.215 Grishina, 1994, Chiral 4-piperidones and their bicyclic analogs. Strategy of stereoselective synthesis (Review), Chem. Heterocycl. Compd., 30, 1619 T.C. Kram D.A. Cooper A.C. Allen Behind the identification of China White Anal. Chem. 53 1981 1379A 1368A Cooper, 1986, Identification of fentanyl derivatives, J. Forensic. Sci., 31, 511, 10.1520/JFS12283J Heagy, 1986, TLC of fentanyl and 3-methylfentanyl mixtures, Microgram, 19, 91 Esposito, 1991, The synthetic drug 3-methylfentanyl: Identification and quantitation of powdered samples, J. Forensic Sci., 36, 86, 10.1520/JFS13009J Kanamori, 2017, Characterization and differentiation of geometric isomers of 3-methylfentanyl analogs by gas chromatograph/mass spectrometry, liquid chromatography/mass spectrometry, and nuclear magnetic resonance spectroscopy, J. Forensic Sci., 10.1111/1556-4029.13395 Cheng, 1982, Structural information from tandem mass spectrometry for China White and related fentanyl derivatives, Anal. Chem., 54, 2204, 10.1021/ac00250a016