Thiamine Hydrochloride Catalyzed Synthesis of 1,2,4‐Triazolidine‐3‐thiones in Aqueous Medium

In the present work, the catalytic potential of natural organocatalyst thiamine hydrochloride is explored for the synthesis of 1,2,4‐triazolidine‐3‐thiones in aqueous medium. The reaction of thiosemicarbazides with various substrates viz aryl/ heteroaryl aldehydes, isatins, cyclic and aromatic ketones to obtain corresponding 1,2,4‐triazolidine‐3‐thiones have been successfully demonstrated for the first time. The method proposed in this work addresses the green chemistry principles such as biodegradable catalyst, ambient reaction condition, shorter reaction time, high yield of the products, recyclability of catalyst and high atom economy. Catalytic potential of natural organocatalyst thiamine hydrochloride in the reactions of thiosemicarbazides with various substrates viz aryl/heteroaryl aldehydes, isatins, cyclic and aromatic ketones in aqueous medium using greener approach to obtain corresponding 1,2,4‐triazolidine‐3‐thiones is successfully demonstrated for the first time.