5-(3-Cyanophenyl)isoxazole-3-carboxylic Acid synthesis

Yield:956360-07-9 96%

Reaction Conditions:

Stage #1: Methyl 5-(3-cyanophenyl)isoxazole-3-carboxylatewith lithium hydroxide;water in tetrahydrofuran at 70; for 0.5 h;
Stage #2: with hydrogenchloride;water in tetrahydrofuran; pH=2;

Steps:

12.D

Step D: [5-(3-cyanophenyl)isoxazole-3-carboxylic acid To the product from Step 12C (660 mg, 2.89 mmol) in THF (10 ml), was added LiOH (6.9 ml of a 0.5 M solution) and the mixture was stirred at 70° C. for 30 min. The mixture was cooled, diluted with water and acidified with 1N HCl to pH 2 and filtered to give 597 mg of the product as a white solid (96% yield).¹H NMR (300 MHz, DMSO-d6): δ (ppm) 14.10 (broad s, 1H), 8.48 (s, 1H), 8.27 (d, 1H), 8.01(d, 1H), 7.78 (dd, 1H), 7.60(s, 1H).

References:

US2007/259860,2007,A1 Location in patent:Page/Page column 17