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

Abstract

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.

Ficus benghalensisleaf extract in biosynthesis of Fe3O4for Fe3O4@Ag‐S‐CH2‐COOH: A novel catalyst for synthesis of new 3,4‐dihydropyrimidin‐2(1H)‐ones and their anticancer evaluation

“…Further, model reaction without catalyst was continued for a further 8 h. We observed no improvement in the yield of the product beyond 50% even after the next 8 h, confirming catalytic role of Fe 3 O 4 @Ag‐S‐CH 2 ‐COOH MNPs. Separation and recyclability of catalysts [ 40 ] used in organic transformations are momentous in viewpoint of commercialization. The Fe 3 O 4 @Ag‐S‐CH 2 ‐COOH MNPs were separated using external magnet and washed with diethyl ether.…”

“…Separation and recyclability of catalysts [40] used in organic transformations are momentous in viewpoint of commercialization. The Fe 3 O 4 @Ag-S-CH 2 -COOH MNPs were separated using external magnet and washed with diethyl ether.…”

Recent Advances of Thiamine in Organic Synthesis

“…In 2019, Sankpal and colleagues first developed an efficient and green VB 1 ‐catalyzed methodology for the synthesis of 1,2,4‐triazolidine‐3‐thiones from thiosemicarbazides with various substrates such as aryl aldehydes, cyclic ketones, aryl ketones and isatins (Scheme 9). [27] The recovery of VB 1 could be achieved by removal of water under reduced pressure and washed with absolute ethanol, after the reaction finished. The catalyst VB 1 could then be reused four times with the product yield from 96 to 92%.…”

“…Plausible reaction mechanism for the formation of 1,2,4-triazolidine-3-thiones promoted by VB 1 . Reproduced with permission from Ref [27]…”