Facile and Green Chemistry Access to 5‐aryl‐1,2,4‐Triazolidine‐3‐thiones in Aqueous Medium

Abstract

A clean, cost-effective and very practical approach has been disclosed for the one-pot, cyclo condensation of aromatic aldehydes with different thiosemicarbazides in aqueous ethanol leading to pharmaceutically diverse 5-aryl-1,2,4-triazolidine-3thiones in good yields under neutral reaction conditions. Simple operational procedure, high product yield, rapid and use of green solvent system make this protocol economical as well as environmentally benevolent.

Transalkylidation reaction: green, catalyst-free synthesis of thiosemicarbazones and solving the NMR conflict between their acyclic structure and intramolecular cycloaddition products

“…Cyclocondensation of thiosemicarbazide with aldehydes could afford either 1,2,4-triazolidine-3-thiones or 2-amino-1,3,4-thiadiazoline using different reaction conditions (45)(46)(47)(48)(49)(50)(51)(52)(53)(54)(55)(56). We observed that there is a structural elucidation confusion between the open structure of thiosemicarbazone and their cycloaddition product with aldehyde.…”

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

“…General experimental procedure for the synthesis of 1,2,4triazolidine-3-thiones and structure elucidation of novel 1,2,4triazolidine-3-thiones using IR, 1 H and 13 C NMR and Mass is provided in the supporting information. Sulfamic acid [23] (20) EtOH Reflux 30 92 2 [C 16 MPy]AlCl 3 Br [25] (10) H 2 O RT 10 96 3 Catalyst free [31] EtOH 80 15 94 4 N,N-dimethylpyridine-4-amine [24] (20) H 2 O RT 20 95 5 Catalyst free [29] PEG Catalyst free [30] Glycerol 40 96 95 9…”

“…Amongst these, the simplest approach for the synthesis of 1,2,4‐triazolidine‐3‐thiones involves the reaction of aldehydes or ketones with thiosemicarbazides in the presence of catalysts such as sulfamic acid, N,N‐dimethylpyridine‐4‐amine, [C 16 MPy]AlCl 3 Br, [(Py) 2 SO][HSO 4 ], [HMPBSA]HSO 4 , glycine nitrate . Moreover, organic solvents like PEG‐400, glycerol and ethanol endorsing catalyst free conditions have also been reported. However, many of the reported methods suffer from drawbacks like use of toxic catalysts, high reaction temperature, prolong reaction time, expensive precursors, limited substrates etc.…”

Synthesis, Biological Activity, and Molecular Docking Studies of Novel 5‐Substituted‐1,2,4‐Triazole‐3‐thione Derivatives

“…Triazole‐thione compounds show excellent antifungal properties and tend to have environment‐friendly synthesis routes . Several researchers, for example, have obtained triazole‐thionesin high yields by using green solvent systems featuring simple steps and short reaction times …”

“…[4][5][6] Several researchers, for example, have obtained triazole-thionesin high yields by using green solvent systems featuring simple steps and short reaction times. [7] Schiff base compounds are a class of compounds containing the imine (À C=NÀ ) group, which is formed by the condensation of amine and active carbonyl groups through nucleophilic reaction. [8][9][10] Schiff base compounds have a wide range of biological properties, such as antifungal, [11] antibacterial, [12,13] anticancer, [14] anti-inflammation, [15] and anticonvulsant [16] activities.…”