The role of acetone solvent in the reaction of 3-chloropropionyl- and 2-chloropropionyl-isothiocyanate with hydrazine

Abstract

The reaction of 3-chloropropionylisothiocyanate with hydrazine did not give the expected bis(3-chloropropionylthioureido)hydrazine but instead 3-Chloro-N-[5,5-dimethyl-4-(4-oxo-5,6-dihydro-4H-[1,3]thiazin-2-yl)-4,5- dihydro-[1,3,4]thiadiazol-2-yl]-propionamide 2 was obtained with 23.56% yield. On the other hand 2-thiocyanatopropionylisothiocyanate undergoes crisscross cycloaddition leading to the formation of 3,3,7,7-Tetramethyl-tetrahydro-[1,2,4]triazolo[1,2-a][1,2,4]triazole-1,5-dithione 1 with 96.1% yield. The mechanisms involving the acetone solvent for both reactions are discussed. Both compounds were evaluated to their antioxidant activity using DPPH radical scavenging method. The results shows that compound 2 with EC50 > 1000 μM is less active than 1 (EC50 of 76 μM) may be due to the S-alkylated on the structure which eliminated its activity. Compound 1 showed higher activity than ascorbic acid (EC50 of 561.36 μM) so that it is potential as antioxidant agent.