Tetrahedron

Chemistry of biureas—II: Synthesis and cyclisation of thiobiureas derived from (thio) carbonohydrazides and ethoxycarbonyl isothiocyanate

R Esmail, F Kurzer

Index: Esmail,R.; Kurzer,F. Tetrahedron, 1977 , vol. 33, p. 2007 - 2012

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Citation Number: 10

Abstract

Carbonohydrazide and its thio-analogue undergo di-addition with ethoxycarbonyl isothiocyanate. The reaction terminates at the mono-addition stage when one of the hydrazine moieties of the (thio) carbonohydrazide is blocked. The resulting 6-(substiiuted) amino-1-ethoxycarbonyl-thiobiureas and bithioureas are cyclised to the appropriate 1- ethoxycarbonamido-1, 3, 4-thiadiazoles by acids, and to mercapto-1, 2, 4-triazoles by ...