反应详情

4-ethyl-5-iodopyridin-2-amine (15.0 g, 60.48 mmol) was dissolved in 140 mL conc. HCl. NaNO2 was dissolved in 40 mL of water and added drop wise to the above solution at 0° C. Care was taken to prevent the temperature of the reaction mixture from rising above 0° C. When all of the NaNO2 solution was added, the reaction mixture was allowed to warm up to room temperature and was stirred for a further 2 h at room temperature. Progress of the reaction was monitored by GC and HPLC. The reaction mixture was then re-cooled to 0° C. and the pH was adjusted to pH=12 by the addition of sat. NaOH. The mixture was extracted with dichloromethane (2×200 mL) and the solvent removed under vacuum. The crude was purified by silica gel column chromatography eluting with 5% ethyl acetate/hexanes. 8.0 g of desired product was obtained after purification (49% yield).

1. additionadded drop wise to the above solution at 0° C
2. customfrom rising above 0° C
3. temperatureThe reaction mixture was then re-cooled to 0° C.
4. extractionThe mixture was extracted with dichloromethane (2×200 mL)
5. customthe solvent removed under vacuum
6. customThe crude was purified by silica gel column chromatography
7. washeluting with 5% ethyl acetate/hexanes