Hydrochloric Acid → Apalutamide Acid Impurity

Participants

Reaction Steps

A mixture of ethyl 4-(7-(6-cyano-5-(trifluoromethyl)pyridin-3-yl)-8-oxo-6-thioxo-5,7-diazaspiro[3.4]octan-5-yl)-2-fluorobenzoate (Compound 3, 1 g, 2.03 mmol) and NaOH (3M, 10 mL) in MeOH (10 mL) was stirred at room temperature for 18 h. Aqueous HCl (2M) was added to the reaction mixture until the pH=2 and the aqueous layer was extracted with DCM (5×), the organics were combined, dried over sodium sulfate, and evaporated to dryness to afford 900 mg of 4-(7-(6-cyano-5-(trifluoromethyl)pyridin-3-yl)-8-oxo-6-thioxo-5,7-diazaspiro[3.4]octan-5-yl)-2-fluorobenzoic acid as a light yellow solid. 1H NMR (300 MHz, DMSO-d6) δ 13.58 (s, 1H), 9.22 (s, 1H), 8.75 (s, 1H), 8.13 (t, 1H), 7.51 (dd, 1H), 7.43 (dd, 1H), 2.69-2.49 (m, 4H), 2.03-1.93 (m, 1H), 1.63-1.57 (m, 1H).

Provenance & Evidence