3,5-Dimethylpyridine → Penoxsulam

Participants

Reaction Steps

2-Amino-5,8-dimethoxy[1,2,4]triazolo[1,5-c]pyrimidine (7.8 g, 0.040 mol) and 2-(2,2-difluoroethoxy)-6-(trifluoromethyl)benzenesulfonyl chloride (13 g, 0.040 mol) were combined in 3,5-lutidine (31 g, 0.29 mol). The slurry was treated with DMSO (0.040 g, 0.012 eq) and stirred at ambient conditions for 8.5 hours, with a slight rise in temperature noted in the first hours resulting from a reaction exotherm. The reaction slurry was filtered, and the wet cake solids were transferred to a separate vessel and slurried in a mixture of 15% sulfuric acid (80 mL) and acetonitrile (20 mL). The mixture was stirred for 25 minutes, then filtered and the solids washed with water. After drying under vacuum at 55° C., 18 g of product was obtained as a white solid assaying at 97 wt % (90% yield).

Provenance & Evidence