2-(4-fluorophenyl)-3-methyl-1-oxidopyridin-1-ium

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 2-(4-fluorophenyl)-3-methylpyridine 1-oxide (24 g, 0.118 mol) in tetrahydrofuran (200 mL) were added trimethylsilyl cyanide (19.2 mL, 0.153 mol) and dimethylcarbamoyl chloride (14.1 mL, 0.153 mmol), and the mixture was heated under reflux for 2 hr. Ethyl acetate and saturated aqueous sodium hydrogen carbonate solution were added to the reaction mixture, and the mixture was extracted 3 times with ethyl acetate. The combined organic layer was washed with saturated brine, dried over anhydrous magnesium sulfate and filtered, and the solvent was evaporated under reduced pressure. The obtained residue was washed with diethyl ether and collected by filtration to give the title compound (16.7 g, 67%) as a white solid. Under reduced pressure, the filtrate was concentrated, and the obtained residue was purified by silica gel column chromatography (ethyl acetate/hexane=1/9) to give the title compound (3.0 g, 12%) as a white solid. the mixture was heated under reflux for 2 hr the mixture was extracted 3 times with ethyl acetate The combined organic layer was washed with saturated brine dried over anhydrous magnesium sulfate filtered the solvent was evaporated under reduced pressure The obtained residue was washed with diethyl ether collected by filtration

Conditions: temp:50.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of 2-(4-fluorophenyl)-3-methylpyridine (26.8 g, 0.143 mol) and m-chloroperbenzoic acid (purity 69%, 39 g, 0.157 mol) in tetrahydrofuran (100 mL) was stirred with heating at 50° C. for 5 hr. The solvent was evaporated under reduced pressure, and the obtained residue was purified 3 times by silica gel column chromatography (NH silica gel, ethyl acetate) to give a white solid. The obtained solid was washed with ethyl acetate to give the title compound (24.7 g, 85%) as a white solid. The solvent was evaporated under reduced pressure the obtained residue was purified 3 times by silica gel column chromatography (NH silica gel, ethyl acetate) to give a white solid The obtained solid was washed with ethyl acetate