Sodium Methoxide → 1-Methylethyl 2-chloro-4-fluoro-5-(2-methoxy-6-oxo-4-(pentafluoroethyl)-1(6H)-pyrimidinyl)benzoate

Participants

Reaction Conditions

Reaction Steps

The residue, a mixture of isopropyl 2-chloro-5-[2-chloro-6-oxo-4-pentafluoroethyl -1(6H)-pyrimidinyl]-4-fluorobenzoate and isopropyl 2-chloro-5-[6-chloro-2-oxo-4-pentafluoroethyl -1(2H)-pyrimidinyl]-4-fluorobenzoate, is dissolved in 20 ml of methanol and 3.8 ml of a 2N sodium methylate solution are added to the solution while stirring at 25° C. The temperature of the reaction mixture rises to 30° C. The mixture is subsequently stirred for 30 minutes and evaporated to dryness under reduced pressure. The residue is separated by chromatography on a silica gel column using n-hexane/diethyl ether (3:1). The first fraction, which still contains some diethylaniline, is dissolved in diethyl ether and the solution is extracted with 2N hydrochloric acid, washed to neutrality with water and dried over anhydrous sodium sulphate. The organic phase is evaporated to dryness under reduced pressure and the residue is recrystallized from n-hexane. There is obtained isopropyl 2-chloro-4-fluoro-5-[2-methoxy-6-oxo-4-pentafluoroethyl-1(6H)-pyrimidinyl]-benzoate, m.p. 82°-84° C. By further elution of the column with n-hexane/diethyl ether (1:2) there is obtained a second fraction which is recrystallized from diethyl ether/n-hexane. In this manner there is also obtained isopropyl 2-chloro-4-fluoro-5-[6-methoxy-2-oxo-4-pentafluoroethyl -1(2H)-pyrimidinyl]-benzoate, m.p. 127°-129° C.

Provenance & Evidence