Synthesis 1988; 1988(9): 690-693
DOI: 10.1055/s-1988-27672
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Alkyl 2-Methyldithiocarbazates in Heterocyclic Synthesis: Preparation of 2-Alkylthio-1,3,4-thiadiazolium Cations and 2-Thioxo-2,3-dihydro-1,3,4-Oxadiazole Derivatives

P. Molina* , A. Tárraga, A. Espinosa
  • *Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Murcia, E-30001 Murcia, Spain
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Publication History

Publication Date:
18 September 2002 (online)

Alkyl 3-acyl-2-methyldithiocarbazates 2, available from alkyl 2-methyldithiocarbazates and acyl chlorides, undergo ring closure by the action of perchloric acid/acetic anhydride to give 2-alkylthio 3-methyl-1,3,4-thiadiazolium salts 4. Compounds 2 also undergo base-catalyzed cyclization to give 4-methyl-2-thioxo-2,3-dihydro-1,3,4-oxadiazoles 3, which react with trimethyloxonium tetrafluoroborate to give 3-methyl-2-methylthio-1,3, 4-oxadiazolium cations 5. 1-Aroyl-2-ethoxyoxalyl-1-phenylhydrazines 6 undergo cyclization by action of trifluoromethanesulfonic acid/acetic anhydride to yield 2-aryl-5-ethoxycarbonyl-3-phenyl-1,3,4-oxadiazolium salts 7.

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