Dimethyl Sulfoxide → N-(5,8-Dimethoxy[1,2,4]triazolo-[1,5-c]pyrimidin 2-yl)-2-methoxy-4-(trifluoromethyl)-3-pyridinesulfonamide

Participants

Reaction Steps

A mixture of 0.75 g (93.8 mmol) of 2-amino-5,8-dimethoxy[1,2,4]triazolo[1,5-c]pyrimidine, 2.1 g (7.6 mmol) of 2-methoxy-4-(trifluoromethyl)pyridine-3-sulfonyl chloride, and 10 mL of dry acetonitrile was prepared and to this was added at ambient temperature with stirring and means to exclude moisture from the system 0.61 mL (7.6 mmol) of dry pyridine, 43 microliters (0.6 mmol) of dry dimethyl sulfoxide, and a small quantity of dry 4A molecular sieves. The mixture was stirred for 5 days. Another 1.0 g (3.4 mmol) of 2-methoxy-4-(trifluoromethyl) pyridine-3-sulfonyl chloride and 0.30 mL (3.5 mmol) of dry pyridine were added and the mixture stirred another 2 days. Another 0.30 mL (3.5 mmol) of dry pyridine was added and stirring continued for 4 more days. The mixture was then diluted with 100 mL of dichloromethane and the resulting mixture was washed with 2×100 mL of 2N aqueous hydrochloric acid, dried over magnesium sulfate, and concentrated by evaporation under reduced pressure. The tan solid residue was chromatographed on silica gel eluting with a mixture of dichloromethane and ethanol to obtain 0.90 g (54 percent of theory) of the title compound as a white solid melting at 214°-216° C.

Provenance & Evidence