3-(3,4-Difluorophenyl)-2-methylprop-2-enoic acid → 3-(3,4-Difluorophenyl)-2-methylpropanoic acid

HRID 1939351Notes

Reaction equation

HRID 1939351 reaction equation
[F:1][C:2]1[CH:3]=[C:4]([CH:11]=[CH:12][C:13]=1[F:14])[CH:5]=[C:6]([CH3:10])[C:7]([OH:9])=[O:8]>CO.O=[Pt]=O>[F:1][C:2]1[CH:3]=[C:4]([CH:11]=[CH:12][C:13]=1[F:14])[CH2:5][CH:6]([CH3:10])[C:7]([OH:9])=[O:8]

Participants

4

Reactant 1

HCID 539805853-(3,4-Difluorophenyl)-2-methylprop-2-enoic acid

Product 1

HCID 120521423-(3,4-Difluorophenyl)-2-methylpropanoic acid

Reagents, catalysts & solvents 2

HCID 345198Adams' catalystCatalystHCID 887MethanolSolvent

Procedure

28 g (0.141 mol) of 3,4-difluoro-α-methylcinnamic acid, 1 g of PtO2 in 250 ml of MeOH is hydrogenated at 45 p.s.i. until the theoretical uptake is completed. The catalyst is filtered off, and the material evaporated to one-third its volume. A 15% potassium hydroxide solution (10 ml) is added, and the mixture refluxed for 30 minutes when it is poured into water and extracted with ether (2×100 ml). The aqueous layer is acidified with concentrated HCl and ice. The oil which comes out is extracted into ether, the ether solution dried over MgSO4 and evaporated to leave a clear oil which crystallizes. 3,4-difluoro-α-methylhydrocinnamic acid, m.p. 55°-56° C., is isolated.

Workup

  1. filtrationThe catalyst is filtered off
  2. customthe material evaporated to one-third its volume
  3. additionA 15% potassium hydroxide solution (10 ml) is added
  4. temperaturethe mixture refluxed for 30 minutes when it
  5. additionis poured into water
  6. extractionextracted with ether (2×100 ml)
  7. extractionThe oil which comes out is extracted into ether
  8. dry with materialthe ether solution dried over MgSO4
  9. customevaporated
  10. customto leave a clear oil which
  11. customcrystallizes

Sources & evidence

ORD record
ord-410d61c32eda4f3791ef84b13240c03a
Source dataset
uspto-grants-1997_12
Patent number
US05696159

Reaction notes

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