Sulfur Dioxide → 5-Methyl-2-pyridinesulfonamide

Beteiligte Stoffe

Reaktionsschritte

Sec-butyllithium (9.8 ml of 1.3M in cyclohexane) and N,N,N',N'-tetramethylethylenediamine (1.8 ml, 12.2 mmol) were added to a stirred solution of 2-bromo-5-methylpyridine (2 g, 11.6 mmol) at -78° C. under a nitrogen atmosphere. After 90 min sulphur dioxide (approximately 30 ml) was condensed into the reaction mixture using a cold finger and the reaction mixture was slowly warmed to room temperature over 12 h. The reaction mixture was concentrated to dryness and the residue dissolved in ice-water. To this was added a mixture of sodium hydroxide (1.39 g, 35 mmol) and hydroxylamine sulphonic acid (3.9 g, 35 mmol) in water (20 ml). After 24 h the solution was extracted with ethyl acetate, dried (MgSO4) and concentrated. Flash column chromatography (95% dichloromethane/5% methanol) gave the product (250 mg) as a clear oil which crystallised on standing.

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