An approach to shortening the timeframe between the emergence of new compounds on the drugs market and the availability of reference standards: The microscale syntheses of nitrazolam and clonazolam for use as reference materials, utilizing polymer-supported reagents.

Nitrazolam and clonazolam are 2 designer benzodiazepines available from Internet retailers. There is growing evidence suggesting that such compounds have the potential to cause severe adverse events. Information about tolerability in humans is scarce but typically, low doses can be difficult to administer for users when handling bulk material. Variability of the active ingredient in tablet formulations can also be of a concern. Customs, toxicology and forensic laboratories are increasingly encountering designer benzodiazepines, both in tablet and powdered form. The unavailability of reference standards can impact on the ability to identify these compounds. Therefore, the need arises for exploring in-house approaches to the preparation of new psychoactive substances (NPS) that can be carried out in a timely manner. The present study was triggered when samples of clonazolam were received in powdered and tablet form at a time when reference material for this drug was commercially unavailable. Therefore, microscale syntheses of clonazolam and its deschloro analog nitrazolam were developed utilizing polymer-supported reagents starting from 2-amino-2'-chloro-5-nitrobenzophenone (clonazolam) and 2-amino-5-nitrobenzophenone (nitrazolam). The final reaction step forming the 1,2,4-triazole ring moiety was performed within a gas chromatography-mass spectrometry (GC-MS) injector. A comparison with a preparative scale synthesis of both benzodiazepine derivatives showed that microscale synthesis might be an attractive option for a forensic laboratory in terms of time and cost savings when compared with traditional methods of synthesis and when qualitative identifications are needed to direct forensic casework. The reaction by-product profiles for both the micro and the preparative scale syntheses are also presented.

[1]  G. Høiseth,et al.  Blood concentrations of new designer benzodiazepines in forensic cases. , 2016, Forensic science international.

[2]  A. Hassner,et al.  Synthesis of Alkyl Azides with a Polymeric Reagent , 1986 .

[3]  H. Schiebel,et al.  Loss of atomic nitrogen from even-electron ions? A study on benzodiazepines. , 2015, Journal of mass spectrometry : JMS.

[4]  G. Sheldrick.  A short history of SHELX. , 2008, Acta crystallographica. Section A, Foundations of crystallography.

[5]  V. Auwärter,et al.  Characterization of the designer benzodiazepine diclazepam and preliminary data on its metabolism and pharmacokinetics. , 2014, Drug testing and analysis.

[6]  H. Miyano,et al.  Heterocycles. VI. Syntheses of 4H-s-Triazolo [4,3-a] [1,4] benzodiazepines, Novel Tricyclic Psychosedatives , 1973 .

[7]  G. Desiraju,et al.  Molecular complexes of alprazolam with carboxylic acids, boric acid, boronic acids, and phenols. Evaluation of supramolecular heterosynthons mediated by a triazole ring. , 2010, Journal of pharmaceutical sciences.

[8]  L. King,et al.  Designer benzodiazepines: A new challenge , 2015, World psychiatry : official journal of the World Psychiatric Association.

[9]  Madeleine Pettersson Bergstrand,et al.  Identification of main human urinary metabolites of the designer nitrobenzodiazepines clonazolam, meclonazepam, and nifoxipam by nano-liquid chromatography-high-resolution mass spectrometry for drug testing purposes , 2016, Analytical and Bioanalytical Chemistry.

[10]  R. Ardrey,et al.  The decomposition of benzodiazepines during analysis by capillary gas chromatography/mass spectrometry. , 1984, Biomedical mass spectrometry.

[11]  G. Van den Mooter,et al.  Polymorphism of Alprazolam (Xanax): a review of its crystalline phases and identification, crystallographic characterization, and crystal structure of a new polymorph (form III). , 2007, Journal of pharmaceutical sciences.

[12]  Richard J. Gildea,et al.  OLEX2: a complete structure solution, refinement and analysis program , 2009 .

[13]  V. Auwärter,et al.  Detection and identification of the designer benzodiazepine flubromazepam and preliminary data on its metabolism and pharmacokinetics. , 2013, Journal of mass spectrometry : JMS.

[14]  V. Auwärter,et al.  Characterization and in vitro phase I microsomal metabolism of designer benzodiazepines - an update comprising adinazolam, cloniprazepam, fonazepam, 3-hydroxyphenazepam, metizolam and nitrazolam. , 2016, Journal of mass spectrometry : JMS.

[15]  G. Desiraju,et al.  Phenylboronic acids in crystal engineering: Utility of the energetically unfavorable syn,syn-conformation in co-crystal design , 2011 .

[16]  T. Shinozuka,et al.  Case report: Etizolam and its major metabolites in two unnatural death cases. , 2008, Forensic science international.

[17]  G. Sheldrick.  Crystal structure refinement with SHELXL , 2015, Acta crystallographica. Section C, Structural chemistry.

[18]  K. K. Hii,et al.  Applications of phosphine-functionalised polymers in organic synthesis. , 2007, Chemical Society reviews.

[19]  L. Waters,et al.  The emergence of new psychoactive substance (NPS) benzodiazepines: A review. , 2018, Drug testing and analysis.

[20]  F. Vane,et al.  The m/z 91 rearrangement ion in the mass spectra of some 1,4‐benzodiazepines , 1979 .

[21]  V. Auwärter,et al.  Characterization of the four designer benzodiazepines clonazolam, deschloroetizolam, flubromazolam, and meclonazepam, and identification of their in vitro metabolites , 2015, Forensic Toxicology.

[22]  L. Orsolini,et al.  Novel psychoactive substances of interest for psychiatry , 2015, World psychiatry : official journal of the World Psychiatric Association.

[23]  H. Mahdavi,et al.  Staudinger/aza-Wittig reactions utilizing a novel linear polymer-supported triphenylphosphine as a modified liquid-phase reagent , 2009 .

[24]  D. Cech,et al.  A facile solid phase synthesis of 2′- and 3′-aminonucleoside triphosphates , 1996 .

[25]  C. O'brien.  Benzodiazepine use, abuse, and dependence. , 2005, The Journal of clinical psychiatry.

[26]  C. Chidester,et al.  A synthetic approach to new 1,4-benzodiazepine derivatives , 1971 .

[27]  J. Hester,et al.  6-phenyl-4H-s-triazolo[4,3-a][1,4]benzodiazepines which have central nervous system depressant activity. , 1971, Journal of medicinal chemistry.