5-(2-METHOXYPHENYL)-4-(4-METHOXYPHENYL)-4H-1,2,4-TRIAZOLE-3-THIOL synthesis

Yield:-

Reaction Conditions:

in ethanol; for 8 h;Reflux;

Steps:

1.a

2-methoxybenzoyl hydrazide (Lancaster; 0.2 mol) was dissolved in ethanol (100 mL). 4-methoxyphenyl isothiocyanate (Acros; 0.22 mol) was added to this solution. The mixture was maintained under reflux stirring for 8 hours. A control TLC performed after this time showed the formation of the thioureido intermediate. A 15% aqueous solution of KOH (0.24 mol.) was added at this point. The resulting mixture was reflux heated under stirring for 20 h. On completion of the reaction (TLC control) the reaction mixture was concentrated at low pressure. The residue obtained was diluted with water (200 mL) and acidified at pH 4.5 with 2N HC1. The precipitate formed was separated by filtration, washed with water and dried. The crude product was crystallised with dimethylformamide, giving 4-(4-mefhoxyphenyl)-5-(2- methoxyphenyl)-4H-[l,2,4]triazol-3 -thiol (46 g, 74%).

References:

WO2012/59869,2012,A1 Location in patent:Page/Page column 11-12