Lead tetraacetate → p-Methoxyphenylpropionic acid

Temperatur

55 °C

A mixture of p-methoxypropiophenone (2.39 g, 14.5 mmol), 90% lead(IV)acetate (6.45 g, 14.5 mmol), triethylorthoformate (15 ml) and 70% perchloric acid (1.2 ml. 29 mmol) was heated to 55° C. for 18 h. The mixture was cooled and the triethylorthoformate removed under reduced pressure. The residue was dissolved in CHCl3 and the remaining precipitate filtered off and discarded. The CHCl3 solution was then washed with water and evaporated to yield the crude ester. This crude ester product was dissolved in a 10% KOH 1:1 water:methanol solution, which was then refluxed for 3 h. After cooling the methanol was evaporated under reduced pressure and the aqueous solution washed with diethylether (3×25 ml). The aqueous solution was acidified with 2N H2SO4, then washed again with diethylether (3×25 ml). The combined fractions from the second ether wash were dried (Na2SO4) and evaporated to give the propionic acid (1.66 g, 63%).

1. temperatureThe mixture was cooled
2. customthe triethylorthoformate removed under reduced pressure
3. dissolutionThe residue was dissolved in CHCl3
4. filtrationthe remaining precipitate filtered off
5. washThe CHCl3 solution was then washed with water
6. customevaporated
7. customto yield the crude ester
8. customwas evaporated under reduced pressure
9. washthe aqueous solution washed with diethylether (3×25 ml)
10. washwashed again with diethylether (3×25 ml)
11. washThe combined fractions from the second ether wash
12. dry with materialwere dried (Na2SO4)
13. customevaporated

ORD-Eintrag

ord-99151606da9146d283d898a9af3d839d

Quelldatensatz

uspto-grants-2003_11

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US06649648B1