Studies on Pyrazine Derivatives, XLVI: The Synthesis of New Pyrazine Derivatives with N′-(Pyrazine-2-carbonyl)-hydrazinecarbodithioic Acid Methyl Ester Usage

Abstract

4-Ω-alkylsubstituted derivatives of 1,2,4-triazole-2-thiones 2–7 were obtained using the high reactivity of N′-(pyrazine-2-carbonyl)-hydrazinecarbodithioic acid methyl ester 1 towards amines. In the reaction with cysteamine 1,3-thiazaethylene-1,2,4-triazole 8 formed. Aromatic amines and N-aminocycloalkylamines gave thiosemicarbazide derivatives 9–12 under the same conditions. The solution of sodium hydroxide caused the decomposition of compounds 11 and 12 and resulted in 4-piperidino- and 4-morpholino-thiosemicarbazides 13 and 14. Compounds 11 and 12 were cyclized to appropriate 4-substituted 1,2,4-triazole-2-thiones 16 and 17 under the influence of DBU or potassium carbonate solution. The heating of derivative 12 with sulfuric acid led to disubstituted 1,3,4-thiadiazole 18.

Keywords:

• 1,2,4-triazoles
• 4-N-cycloakylamino-thiosemicarbazides
• dithiocarboxylic cid esters
• pyrazine derivatives
• tuberculostatic activity