PREPARATION PROCESS OF CARBOXYLIC ACID DERIVATIVES AND INTERMEDIATES THEREOF

摘要

A cocrystal of (S)-2-hydroxy-3-methoxy-3,3-diphenylpropanoic acid and an amino acid, in particular L-valine or L-2-aminobutyric acid, their preparation processes, as well as the preparation process of Ambrisentan or Darusentan using any of the cocrystals of the invention.