Patent ID: 7495126

Claim:
A process for preparing tetrafluorobenzyl-5-aminosalicylic acid derivative represented by Chemical Formula I and its pharmaceutically acceptable salt, the process is comprised of the following steps: a) oxidation of tetrafluorobenzyl alcohol, represented by Chemical Formula 1, to tetrafluorobenzaldehyde, represented by Chemical Formula 2; b) conversion of tetrafluorobenzaldehyde to tetrafluorobenzilidine-5-aminosalicylic acid derivative, represented by Chemical Formula II, via dehydration-condensation reaction between tetrafluorobenzaldehyde and 5-amino-salicylic acid, represented by Chemical Formula 3, and c) hydrogenation of tetrafluorobenzilidine-5-aminosalicylic acid derivative to tetrafluorobenzyl-5-aminosalicylic acid derivative, represented by Chemical Formula I Wherein, M + represents lithium, sodium or potassium; and R 1, R 2 and R 3 may, independently of one another, be hydrogen or halogen.