Trifluoroacetic acid → 4-(2,4-Difluorobenzyloxy)pyridine-1-oxide

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Reaction Steps

4-[(2,4-difluorobenzyl)oxy]-pyridin-2 (1H)-one (from Step 2) (8.60 g, 36.3 mmol) was stirred in 150 ml dimethylformamide and treated with N-chlorosuccinimide (5.4 g, 39.9 mmol). After 15 hours, the precipitate was collected by filtration (5.11 g, 52%) yeilding a lustrous white solid. The mother liquor was diluted to 500 ml with diethyl ether, providing 2.47 g (25%) in a second crop. 1H-NMR (400 MHz, DMSO-d6) δ 11.87 (s, 1H), 7.60 (quartet, J=6.34 Hz, 1H), 7.43 (d, J=7.58 Hz, 1H), 7.31 (dt, J=10.08, 2.21 Hz, 1H), 7.14 (dt, J 8.65, 1.79 Hz, 1H), 6.44 (d, J=7.49 Hz, 1H), 5.28 (s, 1H). 19F-NMR (400 MHz, DMSO-d6) δ−109.58 (quintet, J=7.75 Hz, 1F), −113.68 (quartet, J=8.68 Hz, 1F). LC/MS tr=4.47 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 272, 274 3:1 (M+H).

Provenance & Evidence