5-fluoro-2-methyl-1-oxidopyridin-1-ium

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

Procedure: The reaction was carried out in a flask vented to a gas scrubber containing aqueous sodium hydroxide solution. The product of Step 5, 5-fluoro-2-picoline-N-oxide (1.0 g, 7.86 mmol) was cooled to 0° C. and concentrated sulfuric acid (4.2 mL) was slowly added, with stirring. Solid potassium nitrate (1.27 g, 12.5 mmol) was then added to this mixture at 0° C., in small portions over a 45 minute period. The reaction mixture was allowed to warm to ambient temperature and was stirred at ambient temperature for 1 hour. Not all of the potassium nitrate had dissolved and the reaction mixture was heated at 50° C. for 0.5 hours and then at 100° C. for 18 hours. The homogeneous reaction solution was poured over ice and the resultant aqueous solution was adjusted to pH 9 with solid potassium carbonate. The aqueous solution was then extracted with 3×80 mL of methylene chloride. The combined organic extract was dried over anhydrous sodium sulfate, filtered and concentrated in vacuo to give 1.084 g (80% yield) of the title compound as a yellow solid, m.p. 107°-108° C.; MS DCI-NH3M/Z: 190 (M+NH4)+ 10%, 173 (M+H)+ 30%, 157 (M-O)+ 50%; 1H NMR (CDCl3) d 2.48 (s, 3H), 8.05 (d, 1H, J=9.0 Hz), 8.31 (d, 1H, J=6.0 Hz). The reaction was carried out in a flask was stirred at ambient temperature for 1 hour the reaction mixture was heated at 50° C. for 0.5 hours The homogeneous reaction solution was poured over ice The aqueous solution was then extracted with 3×80 mL of methylene chloride The combined organic extract was dried over anhydrous sodium sulfate filtered concentrated in vacuo

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

Procedure: The reaction was carried out in a flask vented to a gas scrubber containing aqueous sodium hydroxide solution. The product of Step 5, 5-fluoro-2-picoline-N-oxide (1.0 g, 7.86 mmol) was cooled to 0° C. and concentrated sulfuric acid (4.2 mL) was slowly added, with stirring. Solid potassium nitrate (1.27 g, 12.5 mmol) was then added to this mixture at 0° C., in small portions over a 45 minute period. The reaction mixture was allowed to warm to ambient temperature and was stirred at ambient temperature for 1 hour. Not all of the potassium nitrate had dissolved and the reaction mixture was heated at 50° C. for 0.5 hours and then at 100° C. for 18 hours. The homogeneous reaction solution was poured over ice and the resultant aqueous solution was adjusted to pH 9 with solid potassium carbonate. The aqueous solution was then extracted with 3×80 mL of methylene chloride. The combined organic extract was dried over anhydrous sodium sulfate, filtered and concentrated in vacuo to give 1.084 g (80% yield) of the title compound as a yellow solid, m.p. 107°-108° C.; MS DCI-NH3M/Z: 190 (M+NH4)+ 10%, 173 (M+H)+ 30%, 157 (M-O)+ 50%; 1H NMR (CDCl3) d 2.48 (s, 3H), 8.05 (d, 1H, J=9.0 Hz), 8.31 (d, 1H, J=6.0 Hz). The reaction was carried out in a flask was stirred at ambient temperature for 1 hour the reaction mixture was heated at 50° C. for 0.5 hours The homogeneous reaction solution was poured over ice The aqueous solution was then extracted with 3×80 mL of methylene chloride The combined organic extract was dried over anhydrous sodium sulfate filtered concentrated in vacuo

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

Procedure: To the solution of 5-fluoro-2-picoline obtained in Step 4, at 0° C., was added, with vigorous stirring, a cold solution of 40% peracetic acid (prepared by carefully adding 50 mL of 30% hydrogen peroxide solution to 150 mL of glacial acetic acid). The reaction mixture was heated at reflux temperature (50° C.) for 4 days and then poured into 600 mL of ice water. The aqueous mixture was adjusted to pH 9 by the addition of potassium carbonate and then was stirred at ambient temperature for 4 hours. The aqueous solution was continuously extracted with methylene chloride for 24 hours and the methylene chloride extract was dried over anhydrous sodium sulfate, filtered and concentrated in vacuo to afford 30.8 g (22% yield) of the title compound; MS DCI-NH3M/Z: 128 (M+H)+ base; 1H NMR (CDCl3) d 2.48 (s, 3H), 7.00 (ddd, 1H), 7.22 (dd, 1H), 8.22 (dd, 1H). The reaction mixture was heated The aqueous solution was continuously extracted with methylene chloride for 24 hours the methylene chloride extract was dried over anhydrous sodium sulfate filtered concentrated in vacuo

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

Procedure: The reaction was carried out in a flask vented to a gas scrubber containing aqueous sodium hydroxide solution. The product of Step 5, 5-fluoro-2-picoline-N-oxide (1.0 g, 7.86 mmol) was cooled to 0° C. and concentrated sulfuric acid (4.2 mL) was slowly added, with stirring. Solid potassium nitrate (1.27 g, 12.5 mmol) was then added to this mixture at 0° C., in small portions over a 45 minute period. The reaction mixture was allowed to warm to ambient temperage and was stirred at ambient temperature for 1 hour. Not all of the potassium nitrate had dissolved and the reaction mixture was heated at 50° C. for 0.5 hours and then at 100° C. for 18 hours. The homogeneous reaction solution was poured over ice and the resultant aqueous solution was adjusted to pH 9 with solid potassium carbonate. The aqueous solution was then extracted with 3 X 80 mL of methylene chloride. The combined organic extract was dried over anhydrous sodium sulfate, filtered and concentrated in vacuo to give 1.084 g (80% yield) of the title compound as a yellow solid, m.p. 107°-108° C.; MS DCI-NH3M/Z: 190 (M+NH4)+ 10%, 173 (M+H)+ 30%, 157 (M-O)+ 50%; 1H NMR (CDCl3) d 2.48 (s, 3H), 8.05 (d, 1H, J=9.0 Hz), 8.31 (d, 1H, J=6.0 Hz). The reaction was carried out in a flask to warm to ambient temperage was stirred at ambient temperature for 1 hour The homogeneous reaction solution was poured over ice The aqueous solution was then extracted with 3 X 80 mL of methylene chloride The combined organic extract was dried over anhydrous sodium sulfate filtered concentrated in vacuo

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

Procedure: To the solution of 5-fluoro-2-picoline obtained in Step 4, at 0° C., was added, with vigorous stirring, a cold solution of 40% peracetic acid (prepared by carefully adding 50 mL of 30% hydrogen peroxide solution to 150 mL of glacial acetic acid). The reaction mixture was heated at reflux temperature (50° C.) for 4 days and then poured into 600 mL of ice water. The aqueous mixture was adjusted to pH 9 by the addition of potassium carbonate and then was stirred at ambient temperature for 4 hours. The aqueous solution was continuously extracted with methylene chloride for 24 hours and the methylene chloride extract was dried over anhydrous sodium sulfate, filtered and concentrated in vacuo to afford 30.8 g (22% yield) of the title compound; MS DCI-NH3M/Z: 128 (M+H)+ base; 1H NMR (CDCl3) d 2.48 (s, 3H), 7.00 (ddd, 1H), 7.22 (dd, 1H), 8.22 (dd, 1H). The reaction mixture was heated The aqueous solution was continuously extracted with methylene chloride for 24 hours the methylene chloride extract was dried over anhydrous sodium sulfate filtered concentrated in vacuo

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

Procedure: The reaction was carried out in a flask vented to a gas scrubber containing aqueous sodium hydroxide solution. The product of Step 5, 5-fluoro-2-picoline-N-oxide (1.0 g, 7.86 mmol) was cooled to 0° C. and concentrated sulfuric acid (4.2 mL) was slowly added, with stirring. Solid potassium nitrate (1.27 g, 12.5 mmol) was then added to this mixture at 0° C., in small portions over a 45 minute period. The reaction mixture was allowed to warm to ambient temperage and was stirred at ambient temperature for 1 hour. Not all of the potassium nitrate had dissolved and the reaction mixture was heated at 50° C. for 0.5 hours and then at 100° C. for 18 hours. The homogeneous reaction solution was poured over ice and the resultant aqueous solution was adjusted to pH 9 with solid potassium carbonate. The aqueous solution was then extracted with 3 X 80 mL of methylene chloride. The combined organic extract was dried over anhydrous sodium sulfate, filtered and concentrated in vacuo to give 1.084 g (80% yield) of the title compound as a yellow solid, m.p. 107°-108° C.; MS DCI-NH3M/Z: 190 (M+NH4)+ 10%, 173 (M+H)+ 30%, 157 (M-O)+ 50%; 1H NMR (CDCl3) d 2.48 (s, 3H), 8.05 (d, 1H, J=9.0 Hz), 8.31 (d, 1H, J=6.0 Hz). The reaction was carried out in a flask to warm to ambient temperage was stirred at ambient temperature for 1 hour The homogeneous reaction solution was poured over ice The aqueous solution was then extracted with 3 X 80 mL of methylene chloride The combined organic extract was dried over anhydrous sodium sulfate filtered concentrated in vacuo

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

Procedure: To the solution of 5-fluoro-2-picoline obtained in Step 4, at 0° C., was added, with vigorous stirring, a cold solution of 40% peracetic acid (prepared by carefully adding 50 mL of 30% hydrogen peroxide solution to 150 mL of glacial acetic acid). The reaction mixture was heated at reflux temperature (50° C.) for 4 days and then poured into 600 mL of ice water. The aqueous mixture was adjusted to pH 9 by the addition of potassium carbonate and then was stirred at ambient temperature for 4 hours. The aqueous solution was continuously extracted with methylene chloride for 24 hours and the methylene chloride extract was dried over anhydrous sodium sulfate, filtered and concentrated in vacuo to afford 30.8 g (22% yield) of the title compound; MS DCI-NH3M/Z: 128 (M+H)+ base; 1H NMR (CDCl3) d 2.48 (s, 3H), 7.00 (ddd, 1H), 7.22 (dd, 1H), 8.22 (dd, 1H). The reaction mixture was heated The aqueous solution was continuously extracted with methylene chloride for 24 hours the methylene chloride extract was dried over anhydrous sodium sulfate filtered concentrated in vacuo

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

Procedure: The reaction was carried out in a flask vented to a gas scrubber containing aqueous sodium hydroxide solution. The product of Step 5, 5-fluoro-2-picoline-N-oxide (1.0 g, 7.86 mmol) was cooled to 0° C. and concentrated sulfuric acid (4.2 mL) was slowly added, with stirring. Solid potassium nitrate (1.27 g, 12.5 mmol) was then added to this mixture at 0° C., in small portions over a 45 minute period. The reaction mixture was allowed to warm to ambient temperature and was stirred at ambient temperature for 1 hour. Not all of the potassium nitrate had dissolved and the reaction mixture was heated at 50° C. for 0.5 hours and then at 100° C. for 18 hours. The homogeneous reaction solution was poured over ice and the resultant aqueous solution was adjusted to pH 9 with solid potassium carbonate. The aqueous solution was then extracted with 3×80 mL of methylene chloride. The combined organic extract was dried over anhydrous sodium sulfate, filtered and concentrated in vacuo to give 1.084 g (80% yield) of the title compound as a yellow solid, m.p. 107°-108° C.; MS DCI-NH3M/Z: 190 (M+NH4)+ 10%, 173 (M+H)+ 30%, 157 (M-O)+ 50%; 1H NMR (CDCl3) d 2.48 (s, 3H), 8.05 (d, 1H, J=9.0 Hz), 8.31 (d, 1H, J=6.0 Hz). The reaction was carried out in a flask was stirred at ambient temperature for 1 hour the reaction mixture was heated at 50° C. for 0.5 hours The homogeneous reaction solution was poured over ice The aqueous solution was then extracted with 3×80 mL of methylene chloride The combined organic extract was dried over anhydrous sodium sulfate filtered concentrated in vacuo

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

Procedure: To the solution of 5-fluoro-2-picoline obtained in Step 4, at 0° C., was added, with vigorous stirring, a cold solution of 40% peracetic acid (prepared by carefully adding 50 mL of 30% hydrogen peroxide solution to 150 mL of glacial acetic acid). The reaction mixture was heated at reflux temperature (50° C.) for 4 days and then poured into 600mL of ice water. The aqueous mixture was adjusted to pH 9 by the addition of potassium carbonate and then was stirred at ambient temperature for 4 hours. The aqueous solution was continuously extracted with methylene chloride for 24 hours and the methylene chloride extract was dried over anhydrous sodium sulfate, filtered and concentrated in vacuo to afford 30.8 g (22% yield) of the title compound; MS DCI-NH3M/Z: 128 (M+H)+ base; 1H NMR (CDCl3) d 2.48 (s, 3H), 7.00 (ddd, 1H), 7.22 (dd, 1H), 8.22 (dd, 1H). The reaction mixture was heated The aqueous solution was continuously extracted with methylene chloride for 24 hours the methylene chloride extract was dried over anhydrous sodium sulfate filtered concentrated in vacuo

Conditions: temp:20.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Preparation of 5-fluoro-2-picoline was based on E. J. Blanz, F. A. French, J. R. DoAmaral and D. A. French, J. Med. Chem. 1970, 13, 1124–1130. 5-Amino-2-picoline (12.5 g) in ethanol (105 ml) and 50% fluoroboric acid (44.5 ml) was stirred at −5° C. and treated dropwise over 45 mins. with n-butyl nitrite (31.25 ml). The solution was maintained at this temp. for 3 hours, treated with ether (100 ml, precooled to −20° C.) and the solid filtered off, quickly transferred to a flask and covered with hexane (precooled to −20° C.). After allowing to warm to approx. 20° C. and standing for 3 days the hexane was decanted and 2M NaOH solution added until basic (pH10). The mixture was filtered and the filtrate extracted with dichloromethane (10×200 ml). The organic solution was dried, evaporated to 200 ml and treated with m-chloroperbenzoic acid (26.5 g). After stirring 16 hours the solution was washed with excess aqueous sodium bicarbonate and the aqueous re-extracted with dichloromethane (10×200 ml). The organic fraction was dried and evaporated and the residue chromatographed (15% EtOH/EtOAc) to give the product (5.5 g). treated dropwise over 45 mins The solution was maintained at this temp the solid filtered off quickly transferred to a flask covered with hexane (precooled to −20° C.) standing for 3 days the hexane was decanted 2M NaOH solution added until basic (pH10) The mixture was filtered the filtrate extracted with dichloromethane (10×200 ml) The organic solution was dried evaporated to 200 ml treated with m-chloroperbenzoic acid (26.5 g) was washed with excess aqueous sodium bicarbonate the aqueous re-extracted with dichloromethane (10×200 ml) The organic fraction was dried evaporated the residue chromatographed (15% EtOH/EtOAc)

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

Procedure: The reaction was carried out in a flask vented to a gas scrubber containing aqueous sodium hydroxide solution. The product of Step 5, 5-fluoro-2-picoline-N-oxide (1.0 g, 7.86 mmol) was cooled to 0° C. and concentrated sulfuric acid (4.2 mL) was slowly added, with stirring. Solid potassium nitrate (1.27 g, 12.5 mmol) was then added to this mixture at 0° C., in small portions over a 45 minute period. The reaction mixture was allowed to warm to ambient temperage and was stirred at ambient temperature for 1 hour. Not all of the potassium nitrate had dissolved and the reaction mixture was heated at 50° C. for 0.5 hours and then at 100° C. for 18 hours. The homogeneous reaction solution was poured over ice and the resultant aqueous solution was adjusted to pH 9 with solid potassium carbonate. The aqueous solution was then extracted with 3 X 80 mL of methylene chloride. The combined organic extract was dried over anhydrous sodium sulfate, filtered and concentrated in vacuo to give 1.084 g (80% yield) of the title compound as a yellow solid, m.p. 107°-108° C.; MS DCI-NH3M/Z: 190 (M+NH4)+ 10%, 173 (M+H)+ 30%, 157 (M-O)+ 50%; 1H NMR (CDCl3) d 2.48 (s, 3H), 8.05 (d, 1H, J=9.0 Hz), 8.31 (d, 1H, J=6.0 Hz). The reaction was carried out in a flask to warm to ambient temperage was stirred at ambient temperature for 1 hour The homogeneous reaction solution was poured over ice The aqueous solution was then extracted with 3 X 80 mL of methylene chloride The combined organic extract was dried over anhydrous sodium sulfate filtered concentrated in vacuo

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

Procedure: To the solution of 5-fluoro-2-picoline obtained in Step 4, at 0° C., was added, with vigorous stirring, a cold solution of 40% peracetic acid (prepared by carefully adding 50 mL of 30% hydrogen peroxide solution to 150 mL of glacial acetic acid). The reaction mixture was heated at reflux temperature (50° C.) for 4 days and then poured into 600 mL of ice water. The aqueous mixture was adjusted to pH 9 by the addition of potassium carbonate and then was stirred at ambient temperature for 4 hours. The aqueous solution was continuously extracted with methylene chloride for 24 hours and the methylene chloride extract was dried over anhydrous sodium sulfate, filtered and concentrated in vacuo to afford 30.8 g (22% yield) of the title compound; MS DCI-NH3M/Z: 128 (M+H)+ base; 1H NMR (CDCl3) d 2.48 (s, 3H), 7.00 (ddd, 1H), 7.22 (dd, 1H), 8.22 (dd, 1H). The reaction mixture was heated The aqueous solution was continuously extracted with methylene chloride for 24 hours the methylene chloride extract was dried over anhydrous sodium sulfate filtered concentrated in vacuo