4-CYANO-3,5-DIFLUOROPHENYLBORONIC ACID synthesis

Yield:-

Reaction Conditions:

Stage #1: 2,6-difluoro-4-(4,4,5,5- tetramethyl-1,3,2-dioxaborolan-2-yl)benzonitrilewith sodium periodate;ammonium acetate;water in acetone at 20;
Stage #2: with sodium hydroxide in water at 0; for 0.5 h;
Stage #3: with hydrogenchloride in water at 0; pH=2;

Steps:

131

Intermediate 131; (4-Cvano-3,5-difluorophenyl)boronic acid; 2,6-Difluoro-4-(4,4,5,5-tetramethyl-1 ,3,2-dioxaborolan-2-yl) benzonitrile (55 g) was dissolved in acetone (1 L) and water (1 L). T this stirred mixture was added NaIO₄ (160 g) and NH₄OAc (5 Og). The reaction mixture was stirred at room temperature overnight and then filtered. The filtrate was evaporated under vacuum at 40 ⁰C until most of acetone was removed. The residue was cooled to 0 ⁰C and 2N NaOH (1 L) solution was added with stirring over 30 minutes. The mixture was filtered, and the filtrate was washed with CH₂CI₂ (1 L). To the aqueous layer was added 5N hydrochloric acid at 0 ⁰C until pH=2. The resulting solid was filtered and then dissolved in EtOAc (1.5 L), dried over Na₂SO₄, filtered and evaporated under vacuum to provide 30 g of the title compound as a white solid.

References:

WO2010/59658,2010,A1 Location in patent:Page/Page column 205-206