Andrew Allen

Identification of Fentanyl Derivatives

An interpretative approach to the identification of fentanyl homologs and analogs is presented. The techniques employed are liquid/liquid extractions; capillary gas chromatography; and infrared, mass, and nuclear magnetic resonance spectral characterization. Spectral data are presented for eight fentanyl derivatives of clandestine origin.

Methamphetamine from Ephedrine: I. Chloroephedrines and Aziridines

Illicit methamphetamine clandestinely synthesized from ephedrine via reduction of chloroephedrine is discussed. The stereochemistry, mechanism, synthetic impurities, and analysis of clandestine methamphetamine samples is addressed. Stereochemical relation of (+)methamphetamine to its initial precursor (−)ephedrine or (+)pseudoephedrine is achieved by detection of (+)chloropseudoephedrine or cis-1,2-dimethyl-3-phenylaziridine, in the case of the first, and (-)chloroephedrine or trans-1,2-dimethyl-3-phenylaziridine in the case of the latter.

Reversed-phase high-performance liquid chromatographic separation of fentanyl homologues and analogues. II: Variables affecting hydrophobic group contribution

Abstract The effects of organic modifier, stationary phase, hydrophobic substitution, and temperature on the group contribution values for 26 homologues and analogues of the drug fentanyl were studied. Using equations relating group contribution to molecular connectivity, it was found that hydrophobic selectivity is approximately independent of mobile phase composition for mixtures commonly employed in solvent optimization schemes based on overlapping resolution mapping. Similarly, hydrophobic selectivity was also found to be almost identical on both a silica-based Partisil 10-ODS-3 column and a polymer-based PRP-1 column under normalized time conditions. In contrast, hydrophobic selectivity was found to depend on the position of methylene substitution on the parent fentanyl molecule and the type of substituent. For all mobile phases studied there is a small decrease in group contribution values with increases in temperature.

The Cocaine Diastereoisomers

In the past, it has been argued in court, from a theoretical basis, that the techniques available to the forensic chemist would differentiate the “cocaines.” This work has moved that argument from the realm of the theoretical into that of experimental fact. The techniques of infrared spectroscopy (IR), nuclear magnetic resonance (NMR), and mass spectrometry (MS) will unequivocally identify the racemic cocaine diastereoisomer. In addition, this work shows that the enantiomeric form of cocaine can be assigned by crystal tests, IR, and melting point techniques. The pure enantiomers of allococaine and pseudoallococaine were not isolated. This does not create a problem because the techniques of NMR and MS, as performed in this study, will not differentiate enantiomers. Therefore, the logical sequence of first identifying the diastereoisomer (via IR, MNR, or MS) and then determining the chirality by crystal tests, IR, melting points, or optical rotation measurements is valid.

Reversed-Phase High-Performance Liquid Chromatographic Separation of Fentanyl Homologues and Analogues. I. An Optimized Isocratic Chromatographic System Utilizing Absorbance Ratioing

Abstract An optimized isocratic chromatographic system was developed using overlapping resolution mapping for the reversed-phase separation of 26 fentanyl homologues and analogues. The system consisted of a Partisil 10-ODS-3 column with a quaternary mobile phase consisting of phosphate buffer, methanol, acetonitrile and tetrahydrofuran. All 26 compounds were distinguished when UV detection at 215nm was employed in series with UV detection at 230nm.

Isolation, separation and detection via high-performance liquid chromatography of acidic and neutral acetylated rearrangement products of opium alkaloids

Abstract The isolation, separation and detection of acidic and neutral acetylated rearrangement products of opium alkaloids, which are major sources of heroin processing impurities, are described. Preparative reversed-phase high-performance liquid chromatography with the aid of a micro-computer has been utilized for the isolation of product obtained from the action of acetic anhydride on thebaine and noscapine alkaloids. Results obtained show that a high-speed C 18 analytical column (3 μm particle size, 3.0 cm × 4.6 mm I.D.) containing a monomeric bonded phase can be used to develop separations for a polymeric bonded-phase preparative column (10 μm particle size, 25 cm × 22 mm I.D.). An optimized reversed-phase separation was developed for the acetylated thebaine and noscapine compounds and for acetylated rearrangement products from three other opium alkaloids: morphine, codeine and norlaudanosine. Ultraviolet, fluorescence and electrochemical detection were compared for these compounds. A detection system optimized in terms of sensitivity and selectivity was developed utilizing two variable-wavelength UV detectors, programmable fluorescence detector, and an electrochemical detector in series.

.DELTA.16,17-Dehydroheroinium chloride: synthesis and characterization of a novel impurity detected in illicit heroin

Synthese de la deshydro-15 heroine et des chlorure et acetate de deshydro-16 heroinium par acetylation du N-oxyde de morphine. Etude des spectres IR, RMN 1 H, RMN 13 C et de masse

Synthetic Cocaine Impurities

The compounds 3-aminomethyl-2-methoxycarbonyl-8-methyl-8-azabicyclo(3.2.1.) oct-2-ene (1), 3-benzoyloxy-2-methoxycarbonyl-8-methyl-8-azabicyclo(3.2.1)oct-2-ene (2), and 3-benzoyloxy-8-methyl-8-azabicyclo(3.2.1)oct-2-ene (3) have been detected in clandestine synthetic cocaine samples. Synthetic rationalization, chromatographic separation (gas liquid chromatography), and spectroscopic information (infrared, 1H nuclear magnetic resonance. 13C nuclear magnetic resonance, and mass spectrometry) of these compounds are provided.

1H Nuclear Magnetic Resonance of Heroin's D Ring

The 1H nuclear magnetic resonance (NMR) chemical shifts and coupling constants of heroins D ring H-15 alpha, H-15 beta, and H-16 alpha, and H-16 beta are presented. These assignments were accessible through the introduction of a double bond (delta 15,16) in heroin. The resulting compound, delta 15,16 didehydroheroin, was subjected to deuterium exchange or stereoselective reduction or both. Reduced products d1-16 alpha heroin d2-15 alpha, 15 beta-heroin, and d3-15 alpha, 15 beta, 16 alpha-heroin are presented. Heroin with deuterated acetyls is also presented for 1H NMR spectral clarity in the D ring area.