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