Potassium Carbonate → Methyl (2R)‐2‐{4‐[(5‐chloro‐3‐fluoropyridin‐2‐ yl)oxy]phenoxy}propanoate

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Reaction Steps

A solution of 24 g (0.1 mol) of 4-(5-chloro-3-fluoropyridin-2-yloxy)-phenol in 80 ml of dimethylsulfoxide is added dropwise to a stirred solution of 13.8 g (0.1 mol) of potassium carbonate in 50 ml of dimethylsulfoxide. When everything is added, the mixture is stirred for 2 hours at room temperature and then 25.8 g (0.1 mol) of (S)(-)-lactic acid-methylester tosylate is added dropwise over 30 minutes. The mixture is heated to 60° and stirred at that temperature for 20 hours, then poured onto ice/water and the organic material is extracted three times with ether. The ether-layer is washed with water and saturated salt solution, dried over magnesium sulfate, filtered and evaporated. The residue is passed for purification through a silicagel column with a hexane/ethyl acetate 3:1 solvent. After distillation of the solvent, 26 g of a clear oil of the above ester is obtained ([α]D20 =+38.8±0.5° 2% in acetone).

Provenance & Evidence