Hydrochloric Acid → 2-(4-Hydroxyphenyl)propionic acid

A 13.6 g. portion of 4-hydroxyacetophenone was dissolved in 50 ml. of dimethylformamide, and 0.1 g. of sodium hydroxide and 2.5 g. of 5% palladium-on-carbon hydrogenation catalyst was added. The mixture was placed in a Parr hydrogenator at 45° for 3.5 hours, with shaking, and was then shaken at ambient temperature for 16.5 hours. The mixture was then filtered to remove the catalyst, and the solution was added to 5.4 g. of sodium cyanide in a Pyrex flask. The mixture was stirred at 130° for 6 hours, and was then evaporated under vacuum to obtain an oily residue. The residue was dissolved in 38 ml. of 50% aqueous sodium hydroxide and 38 ml. of water, and was stirred under reflux for 8 hours. Its pH was then adjusted to 2.0 with concentrated hydrochloric acid, 50 ml. of water was added, and the mixture was heated to reflux. It was filtered at the reflux temperature through a filter aid pad, and the filtrate was cooled and extracted twice with 125 ml. portions of ethyl acetate. The organic layers were combined and evaporated under vacuum to an oil. To it was added 50 ml. of toluene, followed by 50 ml. of hexane. The product crystallized within a few minutes, and the suspension was stirred for 1 hour before it was filtered. The solids were dried under vacuum at 40° to obtain 14.5 g. of the desired product, identical to that of Example 1. Its melting point was 127°-129°, and the yield was 85.8% of the theoretical yield.

1. stirringwas then shaken at ambient temperature for 16.5 hours
2. filtrationThe mixture was then filtered
3. customto remove the catalyst
4. additionthe solution was added to 5.4 g
5. stirringThe mixture was stirred at 130° for 6 hours
6. customwas then evaporated under vacuum
7. customto obtain an oily residue
8. dissolutionThe residue was dissolved in 38 ml
9. temperatureunder reflux for 8 hours
10. temperaturethe mixture was heated to reflux
11. filtrationIt was filtered at the reflux temperature through a filter aid pad
12. temperaturethe filtrate was cooled
13. extractionextracted twice with 125 ml
14. customevaporated under vacuum to an oil
15. additionTo it was added 50 ml
16. customThe product crystallized within a few minutes
17. stirringthe suspension was stirred for 1 hour before it
18. filtrationwas filtered
19. customThe solids were dried under vacuum at 40°
20. customto obtain 14.5 g

ORD record

ord-c67a095a53114c00bbb53487491bc27e

Source dataset

uspto-grants-1983_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04415751