Dimethyl Sulfate → HCID 19745820, compound

Participants

Reaction Steps

A mixture of 27.50 g of 3-[6-fluoro-2-oxo-3-(2-propynyl)-5-benzothiazolinyl]-6-trifluoromethyl-2,4(1H,3H)-pyrimidinedione (see Example 1), 10.80 g of dimethyl sulphate and 9.08 g of sodium carbonate in 250 ml of acetone is heated at the boiling temperature while stirring for 1.5 hours. After cooling the solid constituent is filtered off under suction and washed with acetone. The filtrate is then evaporated to dryness under reduced pressure, the residue is dissolved in 350 ml of ethyl acetate and the solution is washed three times with 300 ml of water each time. Subsequently, the organic phase is dried over anhydrous sodium sulphate and evaporated to dryness under reduced pressure, and the resinous residue is purified by chromatography on 1.5 g of silica gel using ethyl acetate/n-hexane (1:3) as the eluent. The first fraction is recrystallized from ethyl acetate/diethyl ether (1:1), whereby there is obtained 6-fluoro-5-[2-methoxy-6-oxo-4-trifluoromethyl-1(6H)-pyrimidinyl]-3-(2-propynyl)-2-benzothiazolinone, m.p. 191°-192° C. The 2nd fraction is recrystallized from diethyl ether/n-hexane (1:1) and there is thus obtained 3-[6-fluoro-2-oxo-3-(2-propynyl)-5-benzothiazolinyl]-1-methyl-6-trifluoromethyl-2,4(1H,3H)-pyrimidinedione, m.p. 190°-192° C.

Provenance & Evidence