Production of an amino-hydroxy-benzoic acid hydrate salt, useful for the synthesis of pharmaceutical agents and additives, comprises contacting a solution of the acid in a polar solvent with a protonic acid and an activated carbon

摘要

A process for the production of an optionally substituted amino-hydroxy-benzoic acid hydrate salt comprises contacting a solution containing an amino-hydroxy-benzoic acid and/or its anions in a polar solvent having a pH of 4 with a protonic acid H2A and an activated carbon at 0-200 degreesC, separating the solid from the mixture from step and isolating the hydrate salt from the solution. A process for the production of an optionally substituted amino-hydroxy-benzoic acid hydrate salt (I) of formula (1) comprises: (1) contacting a solution containing an amino-hydroxy-benzoic acid corresponding to the salt (I) and/or its anions in a polar solvent having a pH of 4 with a protonic acid H2A and an activated carbon at 0-200 degreesC; (2) separating the solid from the mixture; and (3) isolating the hydrate salt (I) from the solution. X1 = OH; X2 = NH3+; R1-R3 = H, 1-30C optionally unsaturated acyclic, cyclic, aliphatic, aromatic or araliphatic group whereby R2 and R3 are optionally bonded to each other; Aa- = anion of a protonic acid; a = whole positive number Independent claims are also included for: (1) the resulting amino-hydroxy-benzoic acid hydrate salt (I); (2) amino-hydroxy-benzoic acids of formula (2) prepared by treatment of the hydrate salt (I) with a base. X1 = OH; X3 = NH2