反应详情

A mixture of 2-methoxy-5-cyanopyridine (61.26 g), semicarbazide hydrochloride (76.4 g), sodium acetate (74.92 g), ethanol (1300 ml) and water (400 ml) was hydrogenated at 344 kPa using Raney nickel catalyst (1.0 g). The mixture was evaporated to a volume of 500 ml, water (1000 ml) was added and the mixture was allowed to stand at 0° overnight. The mixture was filtered and the solid was washed with water and dissolved in 10% hydrochloric acid (1000 ml). Formaldehyde solution (36% w/v, 450 ml) was added and the mixture was warmed for 15 minutes, allowed to cool and was added to a solution of sodium acetate (298.5 g) in water (900 ml). This mixture was extracted with ether (3×500 ml) and the combined extracts were successively washed with aqueous potassium carbonate and water and were dried and evaporated to give 6-methoxypyridine-3-carboxaldehyde (31.5 g, 50%) m.p. 48°-49°.

1. customThe mixture was evaporated to a volume of 500 ml, water (1000 ml)
2. additionwas added
3. filtrationThe mixture was filtered
4. washthe solid was washed with water
5. dissolutiondissolved in 10% hydrochloric acid (1000 ml)
6. additionFormaldehyde solution (36% w/v, 450 ml) was added
7. temperaturethe mixture was warmed for 15 minutes
8. temperatureto cool
9. additionwas added to a solution of sodium acetate (298.5 g) in water (900 ml)
10. extractionThis mixture was extracted with ether (3×500 ml)
11. washthe combined extracts were successively washed with aqueous potassium carbonate and water
12. customwere dried
13. customevaporated