Process for preparing flunixin and intermediates thereof

A process for preparing flunixin and pharmaceutically acceptable salts thereof, comprising:

• a) methylating a compound of formula (III):
• ##STR19## wherein Z is hydrogen to give compound (V) ##STR20## wherein Z is defined as before;
• b)In a first alternative, for compounds of formula (V) wherein Z is H, separating compound (V) from the reaction mixture;
• and hydrolyzing compound (V) with acid to give MTA;
• or
• In a second alternative, for compounds of formula (V) wherein Z is H, hydrolyzing the reaction mixture with acid;
• and from the reaction mixture, separating out MTA;
• c) converting 2-methyl-3-trifluoromethylaniline (MTA) from either of the above alternatives in step b) to 2-[[2-methyl-3-(trifluoromethyl) phenyl]amino]-3-pyridinecarboxylic acid (flunixin) or pharmaceutically acceptable salts thereof.