2,4-Dihydro-5-methoxy-4-methyl-3H-1,2,4-triazol-3-one → Thiencarbazone-methyl

Participants

Reaction Conditions

Reaction Steps

12.9 g of 5-methoxy-4-methyl-2,4-dihydro-3H-1,2,4-triazol-3-one (3) (100 mmol) were initially charged in 200 ml of xylene and heated to 70° C. At this temperature, 119 g of a 22% solution of methyl 4-(isocyanatosulfonyl)-5-methylthiophene-3-carboxylate (2) (100 mmol) in dry xylene were metered in. The mixture was stirred at 70° C. for a further 5.8 h. Subsequently, workup was effected at room temperature by filtering the precipitated product. After washing with 50 ml of xylene and subsequently drying, 36.4 g of methyl 4-({[(3-methoxy-4-methyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl)carbonyl]amino}-sulfonyl)-5-methylthiophene-3-carboxylate (4) (91% of theory, content relative to standard: 97.5%) of melting point 201° C. were obtained.

Provenance & Evidence