methyl 5-hydroxy-1-oxidopyridin-1-ium-2-carboxylate

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

Procedure: To a suspension of methyl 5-hydroxypyridin-2-carboxylate (5.30 g) in dichloromethane (75 ml), m-chloroperbenzoic acid (>65%, 11.0 g) is added under ice-cooling, and the mixture is stirred at room temperature for 5 hours. The reaction solution is concentrated under reduced pressure. The residue is suspended in ethyl acetate and collected by filtration to give the title compound (4.62 g). Mother liquor is concentrated under reduced pressure and the resulting residue is purified by silica gel column chromatography (eluent: chloroform to methanol/chloroform=1/5). The resulting solid is suspended in ethyl acetate/diethyl ether and collected by filtration to give the title compound (0.68 g). is added under ice- cooling The reaction solution is concentrated under reduced pressure collected by filtration

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

Procedure: To a suspension of methyl 5-hydroxypyridin-2-carboxylate (5.30 g) in dichloromethane (75 ml), m-chloroperbenzoic acid (>65%, 11.0 g) is added under ice-cooling, and the mixture is stirred at room temperature for 5 hours. The reaction solution is concentrated under reduced pressure. The residue is suspended in ethyl acetate and collected by filtration to give the title compound (4.62 g). Mother liquor is concentrated under reduced pressure and the resulting residue is purified by silica gel column chromatography (eluent: chloroform to methanol/chloroform=1/5). The resulting solid is suspended in ethyl acetate/diethyl ether and collected by filtration to give the title compound (0.68 g). is added under ice- cooling The reaction solution is concentrated under reduced pressure collected by filtration

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

Procedure: To a suspension of methyl 5-hydroxypyridin-2-carboxylate (5.30 g) in dichloromethane (75 ml), m-chloroperbenzoic acid (>65%, 11.0 g) is added under ice-cooling, and the mixture is stirred at room temperature for 5 hours. The reaction solution is concentrated under reduced pressure. The residue is suspended in ethyl acetate and collected by filtration to give the title compound (4.62 g). Mother liquor is concentrated under reduced pressure and the resulting residue is purified by silica gel column chromatography (eluent: chloroform to methanol/chloroform=1/5). The resulting solid is suspended in ethyl acetate/diethyl ether and collected by filtration to give the title compound (0.68 g). is added under ice- cooling The reaction solution is concentrated under reduced pressure collected by filtration

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

Procedure: To a suspension of methyl 5-hydroxypyridin-2-carboxylate (5.30 g) in dichloromethane (75 ml), m-chloroperbenzoic acid (>65%, 11.0 g) is added under ice-cooling, and the mixture is stirred at room temperature for 5 hours. The reaction solution is concentrated under reduced pressure. The residue is suspended in ethyl acetate and collected by filtration to give the title compound (4.62 g). Mother liquor is concentrated under reduced pressure and the resulting residue is purified by silica gel column chromatography (eluent: chloroform to methanol/chloroform=1/5). The resulting solid is suspended in ethyl acetate/diethyl ether and collected by filtration to give the title compound (0.68 g). is added under ice- cooling The reaction solution is concentrated under reduced pressure collected by filtration