Pyridine → isopropyl 2-chloro-5-[2-chloro-6-oxo-4-trifluoromethyl-1(6H)-pyrimidinyl]-4-fluorobenzoate

Participants

Reaction Steps

23.3 g of pyridine are added at room temperature while stirring and cooling to a suspension of 38.8 g of isopropyl 2-chloro-5-[3,6-dihydro-2,6-dioxo-4-trifluoromethyl-1(2H)-pyrimidinyl]-4-fluorobenzoate in 45.2 g of phosphorus oxychloride and 40 ml of toluene. A solution forms rapidly. The temperature is maintained between 30° to 35° C. and, after 15 minutes, a colourless precipitate begins to separate. The reaction mixture is stirred at 30°-35° C. for 45 minutes and is then poured onto 300 g of ice. The mixture is subsequently extracted with 200 ml of ethyl acetate and the organic phase is washed three times with 50 ml of water each time, dried over anhydrous sodium sulphate and evaporated to dryness under reduced pressure. The residue is recrystallized from n-hexane. There is obtained isopropyl 2-chloro-5-[2-chloro-6-oxo-4-trifluoromethyl-1(6H)-pyrimidinyl]-4-fluorobenzoate, m.p. 72°-75° C.

Provenance & Evidence