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    • Fulltext

       

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      Permanent link:
      https://www.ias.ac.in/article/fulltext/jcsc/134/0017

    • Keywords

       

      Zolazepam; 1,3-dimethyl-5-pyrazolone; (5-hydroxy-1,3-dimethyl-1H-pyrazol-4-yl)(2- fluorophenyl) methanone; (5-chloro-1,3-dimethyl-1H-pyrazol-4-yl)(2-fluorophenyl) methanone; 1,3- dimethylchromeno[2,3-c]pyrazol-4(1H)-one.

    • Abstract

       

      The synthesis of (5-chloro-1,3-dimethyl-1H-pyrazol-4-yl)(2-fluorophenyl) methanone (IV) asthe key intermediate in the preparation of zolazepam is reconsidered. The previous report for the preparationof this compound consist of acylation of 5-chloro-1,3-dimethylpyrazole (prepared from chlorination of 1,3-dimethyl-5-pyrazolone) by 2-fluorobenzoyl chloride (II). Herein, the preparation of (IV) via chlorination of(5-hydroxy-1,3-dimethyl-1H-pyrazol-4-yl)(2-fluorophenyl) methanone (III) which was prepared by acylationof 1,3-dimethyl-5-pyrazolone (I) by II is investigated. Different aspects of each step (reaction conditions, sideproducts and workup procedure) were considered and the products and side products were characterized via 1H NMR, 13C NMR and GC-MS techniques.

    • Graphical Abstract

       

      The synthesis of (5-chloro-1,3-dimethyl-1H-pyrazol-4-yl)(2-fluorophenyl) methanone (IV), as the key intermediate in the preparation of zolazepam, via chlorination of (5-hydroxy-1,3-dimethyl-1H-pyrazol-4-yl)(2-fluorophenyl) methanone (III) which was prepared by acylation of 1,3-dimethyl-5-pyrazolone (I) by II is reconsidered. Different aspects of each step (reaction conditions, side products and workup procedure) were considered and the products and side products were characterized via 1H NMR, 13C NMR and GC-MS techniques.

    • Author Affiliations

       

      HOSSEIN FAKHRAIAN1 YASER NAFARI1 MOHAMMAD JAVAD TAGHIZADEH1 ESMAEIL CHAHARDOLI1

      1. Department of Chemistry, Imam Hossein University, Tehran, Iran

    • Dates

       
      Published
      27 January 2022
      Manuscript received
      28 June 2021
      Manuscript revised
      25 October 2021
      Accepted
      5 November 2021

    • Supplementary Material

       

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