Triphenylphosphine → 1-(2,6-difluorophenyl)-4-{[4-fluoro-2-(hydroxymethyl)benzyl]oxy}-6-methylpyridin-2(1H)-one

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Reaction Conditions

Reaction Steps

1-(2,6-Difluorophenyl)-4-hydroxy-6-methylpyridin-2(1H)-one (step 1) (3.0 g, 12.65 mmol) was dissolved in N,N-dimethylformamide and cooled to 0° C. Triphenylphosphine (3.98 g, 15.18 mmol) and diethyl azodicarboxylate (2.39 ml, 15.18 mmol) were added and stirred for 10 minutes. 1,2-Bis(hydroxymethyl)-4-fluorobenzene (2.57 g, 16.44 mmol) was added and stirred at 0° C. for 1 hour, then allowed to warm to room temperature and stirred overnight. LC-MS showed only 1 product, not a mixture of regioisomers, as expected. The reaction was added to water and extracted 3 times with ethyl acetate. The combined organic layers were dried over MgSO4 and evaporated. A Biotage silica column was done using 60% ethyl acetate/hexanes as an eluent. Desired product, with a substantial impurity was obtained. Another Biotage silica column was ran using 30% ethyl acetate/hexanes to obtain pure product. The resulting oil was triturated with diethyl ether to obtain a white solid (720 mg, 15%). 1H NMR (300 MHz, CDCl3) δ 7.51-7.39 (m, 2H), 7.26 (dd, J=9.62, 2.51 Hz, 1H), 7.13-7.01 (m, 3H), 6.03 (d, J=2.42 Hz, 1H), 5.96 (d, J=2.41 Hz, 1H), 5.06 (s, 2H), 4.73 (s, 2H), 2.81 (br s, 1H), 2.02 (s, 3H); LC/MS, tr=2.37 minutes (5 to 95% acetonitrile/water over 5 minutes at 1 ml/min, at 254 nm, at 50° C.), ES-MS m/z 376 (M+H). ES-HR/MS m/z 376.1181 (M+H calcd for C20H16F3NO3 requires 376.1155). Identity of the positional isomer was determined from hmbc, 2-D NMR experiments using H to C 2- and 3-bond coupling.

Provenance & Evidence