Patent ID: 7964723
Filing Date: 2011-06-21
Classification: C07D,Y02P

Abstract:
1. A process to selectively produce a pyridobenzoxazine carboxylic acid hemihydrate, comprising: mixing crude pyridobenzoxazine carboxylic acid and a calculated amount of sodium sulfate decahydrate in an anhydrous solvent system to form a mixture; heating the mixture to form pyridobenzoxazine carboxylic acid hemihydrate, wherein the pyridobenzoxazine carboxylic acid is of formula (I): wherein X is halo; G 1 is carbon; G 2 is oxygen; G 3 is carbon or nitrogen; R 1 is C 1 -C 4 alkyl; and R 2 is C 1 -C 4 alkyl.