Hydrochloric Acid → Methyl 2-(3-hydroxyphenoxy)-3-pyridinylacetate

Methyl 2-(3-methoxyphenoxy)-3-pyridinylacetate (27.2 g) was heated at 115° C. in 47% hydrobromic acid (249 ml) containing hexadecyltributylphosphonium bromide (5.6 g). After 3 hours, the solution was cooled and potassium carbonate added until the pH of the solution was ca. 6. The reaction mixture was extracted (× 5) with ethyl acetate. The organic extracts were dried, filtered and evaporated to give a pale orange solid. The solid was then treated with methanolic hydrogen chloride overnight (from methanol (500 ml) and acetyl chloride (50 ml)). The methanol was removed and the residue dissolved in water. The pH of the solution was adjusted to ca. pH6 with sodium bicarbonate and the solution extracted with ethyl acetate (× 3). The combined organic extracts were dried, filtered and evaporated. The resulting organge solid residue was re-dissolved in dichloromethane and filtered through a plug of silica (eluent ether dichloromethane). Evaporation afforded methyl 2-(3-hydroxyphenoxy)-3-pyridinylacetate as a pale yellow solid (13.28 g, 51%) which was used without further purification.

1. temperaturethe solution was cooled
2. extractionThe reaction mixture was extracted (× 5) with ethyl acetate
3. customThe organic extracts were dried
4. filtrationfiltered
5. customevaporated
6. customto give a pale orange solid
7. customThe methanol was removed
8. dissolutionthe residue dissolved in water
9. extractionthe solution extracted with ethyl acetate (× 3)
10. customThe combined organic extracts were dried
11. filtrationfiltered
12. customevaporated
13. dissolutionThe resulting organge solid residue was re-dissolved in dichloromethane
14. filtrationfiltered through a plug of silica (eluent ether dichloromethane)
15. customEvaporation

ORD record

ord-dbff2dfea51b4f6b862b2a9a029df85e

Source dataset

uspto-grants-1993_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05198444