Potassium Persulfate → 4-(2-Formyl-3-methyl-phenoxy)-butyric acid ethyl ester

Temperature

64 °C

A mixture of copper(II) sulfate pentahydrate (21.98 g, 88.06 mmol) and potassium persulfate (71.42 g, 264 mmol) in water (396 mL) was heated to 63-65° C. to obtain a blue colored solution. Then, a solution of 4-(2,3-dimethyl-phenoxy)-butyric acid ethyl ester (20.81 g, 88.06 mmol) in acetonitrile (220 mL) was added at the above temperature. The resulting light green solution was refluxed for 40 minutes. Then, the reaction mixture was cooled to ˜5° C. in order to precipitate most of the inorganic solids. The resulting solids were collected by filtration and the solid cake was washed with dichloromethane (1.0 L). The two layers of filtrate were separated and the aqueous layer was extracted with dichloromethane (200 mL). The combined organic extracts were washed with brine solution (150 mL) and the organic solution was dried over anhydrous magnesium sulfate. Filtration of the drying agent and the removal of the solvent gave a brown oil. The crude mixture was purified by using a Biotage™ (40 L) column chromatography eluting with 5-10% ethyl acetate in hexanes to obtain 4-(2-formyl-3-methyl-phenoxy)-butyric acid ethyl ester (45.32 g, 94%) as a colorless oil: EI(+)-HRMS m/e calculated for C14H18O4 (M+)+ 250.1205. found 250.1202.

1. customto obtain a blue colored solution
2. temperatureThe resulting light green solution was refluxed for 40 minutes
3. temperatureThen, the reaction mixture was cooled to ˜5° C. in order
4. customto precipitate most of the inorganic solids
5. filtrationThe resulting solids were collected by filtration
6. washthe solid cake was washed with dichloromethane (1.0 L)
7. customThe two layers of filtrate were separated
8. extractionthe aqueous layer was extracted with dichloromethane (200 mL)
9. washThe combined organic extracts were washed with brine solution (150 mL)
10. dry with materialthe organic solution was dried over anhydrous magnesium sulfate
11. filtrationFiltration of the drying agent
12. customthe removal of the solvent
13. customgave a brown oil
14. customThe crude mixture was purified
15. washeluting with 5-10% ethyl acetate in hexanes

ORD record

ord-9b145559512542d08ea1ff8940358dfd

Source dataset

uspto-grants-2012_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08088936B2