Collect. Czech. Chem. Commun. 2003, 68, 792-800

Cyclization of Semicarbazide Derivatives of 3-Methyl-5-thioxo-4,5-dihydro-1H-1,2,4-triazole-4-acetic Acid

Maria Dobosza,*, Monika Pituchaa, Izabela Dybalab and Anna E. Koziołb

a Department of Organic Chemistry, Faculty of Pharmacy, Medical University, Staszica Str. 6, 20-081 Lublin, Poland
b Department of Crystallography, Faculty of Chemistry, Maria Curie-Sklodowska University, 20-031 Lublin, Poland


By the reaction of hydrazide of 3-methyl-5-thioxo-4,5-dihydro-1H-1,2,4-triazole-4-acetic acid (1) with isocyanates, 3-methyl-5-thioxo-4,5-dihydro-1H-1,2,4-triazole-4-acetosemicarbazide derivatives 2 were obtained. Cyclization of these compounds in the presence of 2% NaOH led to the formation of 4,5-dihydro-1H-1,2,4-triazol-5-one derivatives 3, which was confirmed by X-ray analysis of 3b.

Keywords: Triazolines; Triazoles; 1,2,4-Triazolin-5-one; Semicarbazides; Isocyanates; Hydrazides; Cyclizations; X-Ray diffraction.

References: 30 live references.