| 摘要 |
PURPOSE:p-Hydroxymandelic acid is reduced in a solvent of lower alcohol in the presence of a strong-acid type ion exchange resin to produce the titled compound used as a synthetic intermediate of medicines and agricultural chemicals directly, not through its free acid, in high yield. CONSTITUTION:p-Hydroxymandelic acid (PHM) of formulaIis reduced in an alcohol of 1-4C carbon atoms in the presence of a strong-acid type ion exchange resin to give a p-hydroxyphenylacetic ester of formula II (R is alkyl of 1-4C carbon atoms). The amount of alcohol is 5-15mol per 1mol of PHM and the strong-acid type ion exchange resin is 7-13W/V% based on PHM. The reduction reaction is catalytically effected in the presence of a Pd or Pt catalyst and three series of reactions proceed simultaneously. Since free p-hydroxyphenylacetic acid is not formed, the working environment is markedly improved as well as its purification and esterification processes are eliminated. |
