Potassium Acetate → 4-(2,4-difluorobenzyloxy)-1H-pyridin-2-one

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Reaction Conditions

Reaction Steps

4-[(2,4-difluorobenzyl)oxy]pyridine 1-oxide (from Step 1) (30.0 g, 0.127 mol), anhydrous potassium acetate (25 g, 0.25 mol), acetic anydride (25 g, 0.25 mol), and 10 ml acetic acid were combined in a 250-ml round-bottomed flask with overhead stirring and heated to 130° C. for 4 hours. The mixture was concentrated under vacuum, the solids dissolved in 95 ml acetonitrile; 5 ml water, filtered through charcoal and poured into 600 ml ice with stirring. The mixture was allowed to stand overnight at room temperature, then 9.62 g (30%) product collected by filtration as a medium brown solid (adequate for the next step without purification). 1H-NMR (400 MHz, DMSO-d6) δ 11.10 (s, 1H), 7.59 (quartet, J=9.91 Hz, 1H), 7.29 (t, J=10.36 Hz, 1H), 7.21 (d, J=8.20 Hz, 1H), 7.11 (t, J=8.48 Hz, 1H), 5.83 (m, 2H), 5.02 (s, 2H). 19F-NMR (400 MHz, DMSO-d6) δ −109.57 (quintet, J=7.66 Hz, 1F)-113.88 (quartet, J=8.93 Hz, 1F). LC/MS tr=4.29 minutes (0-95% acetonitrile/water, 0.05% trifluoroacetic acid, over 6 minutes at 1 ml/min with detection at 254 nm, at 50° C.) ES-MS m/z 238 (M+H).

Provenance & Evidence