Triphenylphosphine → Ammonia

Participants

Reaction Steps

(3-Methoxy-pyridin-2-yl)-methanol (227 mg, 1.63 mmol), 2-hydroxy-4-bromopyridine (282 mg, 1.63 mmol) and triphenyl phosphine (416 mg, 1.63 mmol) were stirred in dry dichloromethane (10 ml) at 0° C. under an atmosphere of nitrogen. Diethyl azodicarboxylate (242 mg, 1.63 mmol) was added at 0° C. then the reaction was allowed to attain room with stirring overnight. A saturated aqueous solution of sodium hydrogen carbonate was added (10 ml) and the layers were separated. The aqueous portion was extracted with dichloromethane (2×10 ml) and the organic portions were combined, dried (MgSO4) and concentrated under reduced pressure. The crude product was purified by flash silica chromatography eluting first with 0-100% ethyl acetate in petrol and then 10% 7 N methanolic ammonia in dichloromethane to give the 4-bromo-1-(3-methoxy-pyridin-2-ylmethyl)-1H-pyridin-2-one in 57% purity contaminated with 23% 2-hydroxy-4-bromopyridine and 20% triphenyl phosphine oxide by LC-MS (340 mg). The product was used directly in the next step. LC-MS m/z 297 [M+H]+ Rt=2.05 min

Provenance & Evidence