2-benzyl-1-oxidopyridin-1-ium

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

Procedure: Trimethylsilyl cyanide (14.56 g, 19.6 ml, 0.147 moles) was added dropwise to a solution of 2-benzylpyridine-N-oxide (10.86 g, 0.059 moles) and triethylamine (8.91 g, 12.3 ml, 0.088 moles) in acetonitrile (40 ml) at 20° C. After complete addition the mixture was heated under reflux for 20 hours, cooled to room temperature and partitioned between methylene chloride and saturated sodium bicarbonate. The organic layer was washed with water and saturated sodium chloride, and then dried over anhydrous magnesium sulphate. Removal of the solvent gave an orange oil which was purified by column chromatography (silica gel eluted with hexane:ethyl acetate 9:1) to give 2-benzyl-6-cyanopyridine (1.84 g, 16%) as a pale yellow oil. After complete addition the mixture was heated under reflux for 20 hours partitioned between methylene chloride and saturated sodium bicarbonate The organic layer was washed with water and saturated sodium chloride dried over anhydrous magnesium sulphate Removal of the solvent gave an orange oil which was purified by column chromatography (silica gel eluted with hexane:ethyl acetate 9:1)

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

Procedure: A solution of 2-benzylpyridine (10.0 g, 0.059 moles) and hydrogen peroxide (33% w/v, 4.02 g, 12.2 ml, 0.118 moles) in glacial acetic acid (40 ml) was heated at 60° C. for 17 hours. The reaction mixture was cooled to room temperature, the acetic acid evaporated under reduced pressure and the residue dissolved in chloroform. After neutralisation with potassium carbonate (20 g) the chloroform was removed to give 2-benzylpyridine-N-oxide (10.86 g, 99%) as a viscous oil which crystallised on standing. the acetic acid evaporated under reduced pressure the residue dissolved in chloroform After neutralisation with potassium carbonate (20 g) the chloroform was removed

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

Procedure: A stirred solution of 3.0 g (18 mmol) 2-benzylpyridine and 1.65 mL of 30% aqueous hydrogen peroxide in 5.0 mL of acetic acid was heated at 100° C. for 3 hr (S. Hibino and E. Sugino, J. Heterocycl Chem., 1990, 27, 175). After cooling to room temperature, the reaction was diluted with 30 mL ethyl acetate and neutralized with sodium carbonate. The sodium acetate was separated by filtration and the filtrate was dried (sodium carbonate) and concentrated to give a yellow oil. Flash column chromatography on 125 g of silica gel using 7 of L 20% acetone/ethyl acetate furnished 2,58 g (79% yield) of 2-benzylpyridine N-oxide as an amber syrup. The sodium acetate was separated by filtration the filtrate was dried (sodium carbonate) concentrated to give a yellow oil