Hexamethylphosphoramide → 5-(2-Formyl-3-hydroxyphenoxy)pentanoic acid

Ethyl 5-(2-formyl-3-methoxphenoxy)pentanoate (Example 4) (2.0 g, 0.00704 M), sodium thiocresolate (2.06 g, 0.014 M), hexamethylphosphoramide (2.48 ml, 0.014 M) and benzene (10 ml) were placed in a round bottom flask and refluxed for 18 hours. The reaction mixture, containing ethyl 5-(2-formyl-3-hydroxyphenoxy)pentanoate, was then cooled and poured into 2 N sodium hydroxide solution (20 ml). The organic layer was removed, diluted with ether (20 ml), then extracted with 2 N sodium hydroxide solution (2×20 ml). The aqueous layers were combined and extracted with dichloromethane (2×20 ml). The organic layer was discarded and the aqueous layer acidified with concentrated hydrochloric acid. The resulting precipitate was filtered, washed with water and dried in a desiccator over phosphorus pentoxide to give 5-(2-formyl-3-hydroxyphenoxy)pentanoic acid, m.p. 98°-99° C. from ethyl acetate/petrol.

1. temperaturerefluxed for 18 hours
2. temperaturewas then cooled
3. customThe organic layer was removed
4. additiondiluted with ether (20 ml)
5. extractionextracted with 2 N sodium hydroxide solution (2×20 ml)
6. extractionextracted with dichloromethane (2×20 ml)
7. filtrationThe resulting precipitate was filtered
8. washwashed with water
9. dry with materialdried in a desiccator over phosphorus pentoxide

ORD record

ord-261005c37ffd402fb2238eacd4b34f05

Source dataset

uspto-grants-1983_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04410537