反应详情

A solution of methyl 4-ethyl-5-phenylisoxazole-3-carboxylate (194 mg, 0.839 mmol) and 1N aqueous sodium hydroxide (1.26 mL, 1.258 mmol) in methanol (3 mL) was heated to 100° C. for 10 minutes under microwave. The reaction mixture was acidified with acetic acid until the pH was about 4. The mixture was concentrated, and the residue was suspended in water (2 mL) and stirred for 20 minutes. The solid was collected by vacuum filtration and dried to give 4-ethyl-5-phenylisoxazole-3-carboxylic acid (148 mg). The compound had an HPLC ret. time=2.93 min.−Column: YMC S5 COMBISCREEN® 4.6×50 mm; Gradient time: 4 min; Flow rate=4 ml/min; Solvent A=10% MeOH−90% Water−0.2% H3PO; Solvent B=90% MeOH−10% water−0.2% H3PO4; Start % B=0; Final % B=100. LC-MS: M+1=218+.

1. concentrationThe mixture was concentrated
2. filtrationThe solid was collected by vacuum filtration
3. customdried