Methyl Lactate → 2-[4-(4-Chloro-2-fluorophenoxy)phenoxy]propionic acid methyl ester

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Reaction Steps

A mixture of 4-(4-chloro-2-fluorophenoxy)phenol (2.23 g; 0.01 mole), the methanesulfonate of S methyl lactate (18.22 g; 0.1 mole, minimum of 90% optical purity), and potassium carbonate (1.4 g; 0.01 mole) in DMSO (75 ml) was stirred at room temperature for 18 hours. After this period, the mixture was poured into water (500 ml) then extracted into ether (3×100 ml). The ether extracts were dried (MgSO4), and the solvent evaporated. The residue was purified by preparative HPLC using 8:2 hexane-ethylacetate as the eluent. The first peak to elute (after the solvent front) was collected and the solvent evaporated. This gave 2.3 g (17%) of a light yellow oil whose 1H and 19F NMR (CDCl3) were consistent with the assigned structure. This material possessed an optical rotation of +24.68° as measured at 25° C. The refractive index was 1.5466. Attempts to measure the optical purity using the optically active NMR shift reagent tris-[3-(trifluoromethylhydroxymethylene)-d-camphorateo]europium (III) were not successful. Based upon the optical purity of the starting lactate the optical purity is estimated to be between 75 and 95%.

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