New Synthetic Pathways for Thiocarbohydrazide and Salicylaldehyde Azine Compounds

Thiocarbohydrazide synthesis is an important intermediate step for many hydrazine organic synthetic reactions. Synthesis of thiocarbohydrazide can be done by reaction of carbon disulfide with hydrazine (hydrazinolysis) in water at 0°C giving 25% yield (based on [hydrazine]). However, in this article, we achieve a 96% yield (based on [hydrazine]) by carrying out the reaction in methanol at 24°C. The thiocarbohydrazide is then used to synthesize 1,5-bis (2-hydroxybenzaldehyde) dithiocarbohydrazone. By refluxing the latter compound in pyridine at 80°C, it decomposes and rearranges to give salicylaldehyde azine.