• Thiophenes and thiapyrans - Part VIII. A new synthesis of dibenzothiophene and its derivatives; its scope and limitations

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      Permanent link:
      https://www.ias.ac.in/article/fulltext/seca/036/05/0411-0418

    • Keywords

       

      Thiophene; Phosphorus Pentoxide; Cyclohexanone; Bath Temp; Picrate

    • Abstract

       

      A new synthesis of dibenzothiophene (I) which has been extended to its substituted derivatives has been developed. It consists in the condensation of thiophenol with 2-bromocyclohexanone to give 2-phenylmercaptocyclohexanone (II), cyclization of (II) with phosphorus pentoxide to 1:2:3:4-tetrahydrodibenzothiophene and selenium dehydrogenation of the latter compound to give (I) (overall yield 52%).

      Starting with suitably substituted thiophenols, 2-methyl-, 3-methyl and 4-methyldibenzothiophenes and 4-methoxydibenzothiophene have been synthesized. The synthesis of 2-methoxydibenzothiophene could not be completed due to the low yield of 2-methoxy-6:7:8:9-tetrahydrodibenzothiophene. Attempts to cyclize 2-(4′-nitrophenylmercapto)cyclohexanone by means of phosphorus pentoxide by the usual method were unsuccessful.

      The scope and limitations of the new synthesis are discussed.

    • Author Affiliations

       

      K Rabindran1 B D Tilak1

      1. Department of Chemical Technology, University of Bombay, India
    • Dates

       
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