Ethyl 2-(3-cyano-4-isobutoxyphenyl)-4-methyl-5-thiazolecarboxylate

White crystalline powder

Ethyl 2-(3-Cyano-4-isobutoxyphenyl)-4-methyl-5-thiazolecarboxylate is an impurity of Febuxostat (F229000), a xanthine oxidase/xanthine dehydrogenase inhibitor. Used for treatment of hyperuricemia and chronic gout. 40-120 mg/day febuxostat was proven effective in lowering serum urate levels when administered to manage hyperuricemia in patients with gout.

CarboxylatePotassium carbonate (300 g, 2.17 mol) and isobutyl bromide (142.7 g, 1.041 mol) were added to a solution of ethyl-2-(3-cyano-4-hydroxyphenyl)-4-methyl-5-thiazole carboxylate (100 g, 0.347 mol) in dimethylformamide (300 mL), and the reaction mixture was heated at a temperature of about 75°C for about 8 hours. After completion of the reaction, the reaction mixture was cooled to about 40°C, and water was added. The reaction mixture was further cooled to about 0°C and stirred for about 1 hour. The solid thus obtained was filtered, washed with water, and dried to give Ethyl 2-(3-cyano-4-isobutoxyphenyl)-4-methyl-5-thiazolecarboxylate. (Yield: 11 lg, 92.9%)