反应详情

Methyl 4-amino-2,6-diethylpyridine-3-carboxylate (B) (3.94 g) was added to a mixture of 2M sodium hydroxide solution (9.5 ml) and methanol (40 ml) and the mixture was heated at reflux for 16 hours. The solution was cooled to ambient temperature and volatile material was removed by evaporation. The residue was partitioned between ethyl acetate and a mixture of 2M hydrochloric acid (9.5 ml) and water (20 ml). The aqueous phase was separated, water was removed by evaporation and the residue was extracted with ethyl acetate/methanol (1:1 v/v). The combined organic extracts were filtered and solvent was removed from the filtrate by evaporation to give 4-amino-2,6-diethylpyridine-3-carboxylic acid (C) (3.46 g) as a yellow-brown foam; NMR (d6 -DMSO): 1.18(m,6H), 2.64(q,2H), 3.12(q,2H), 6.94(s,1H), 8.28(broad s,2H); mass spectrum (chemical ionisation, ammonia): 195(M+H)+.

1. temperaturethe mixture was heated
2. temperatureat reflux for 16 hours
3. customvolatile material was removed by evaporation
4. customThe residue was partitioned between ethyl acetate
5. additiona mixture of 2M hydrochloric acid (9.5 ml) and water (20 ml)
6. customThe aqueous phase was separated
7. customwater was removed by evaporation
8. extractionthe residue was extracted with ethyl acetate/methanol (1:1 v/v)
9. filtrationThe combined organic extracts were filtered
10. customsolvent was removed from the filtrate by evaporation