反应详情

To 6-methyl-4-(1H)-pyridone-3-carboxylic acid (prepared according to the procedure described in J. Org. Chem., 1972, 37, 1145-1148) (10.0 g, 65.4 mmol) and dry pyridine (5.2 ml) in acetic acid (200 ml) at 100° C. was added bromine (14.6 g, 91.5 mmol) in acetic acid (30 ml) dropwise over 1 hour. Heating was continued for 2 hours then cooled to room temperature. The precipitate which formed on cooling was collected by filtration, and washed with methanol to give the product as a cream coloured solid (10.62 g, 70%). 1H NMR (250 MHz, DMSO-d6) δ14.75 (1H, br s), 13.45 (1H. br s), 8.58 (1H, s), 2.53 (3H, s); MS (ES+) m/z 232/234 MH]+, 214/216 [(M-(H2O))H]+.

1. temperatureHeating
2. customThe precipitate which formed
3. temperatureon cooling
4. filtrationwas collected by filtration
5. washwashed with methanol