Patent ID: 8394959

Claim:
A method of preparing (E)-N-{4-[3-chloro-4-(2-pyridinylmethoxy)anilino]-3-cyano-7-ethoxy-6-quinolinyl}-4-(dimethylamino)-2-butenamide as a maleate salt monohydrate, comprising: i) mixing (E)-N-{4-[3-chloro-4-(2-pyridinylmethoxy)anilino]-3-cyano-7-ethoxy-6-quinolinyl}-4-(dimethylamino)-2-butenamide and maleic acid in a water-alcohol solution at a temperature in the range of between about 50° C. to about 60° C.; ii) cooling said solution to a temperature of about 40° C. and maintaining the cooled solution at about 40° C. for about 12 hours to precipitate the maleate salt; iii) further cooling the cooled solution to room temperature (about 25° C.) over a minimum of 4 hours and maintaining the further cooled solution at room temperature (about 25° C.) for at least 2 hours; and iv) filtering the maintained, further cooled solution to obtain crystalline (E)-N-{4-[3-chloro-4-(2-pyridinylmethoxy)anilino]-3-cyano-7-ethoxy-6-quinolinyl}-4-(dimethylamino)-2-butenamide maleate monohydrate.