65685-55-4

General procedure for the synthesis of 1,2-benzisoxazol-6-ol from 2,4-dihydroxybenzaldehyde oxime: 2,4-dihydroxybenzaldehyde oxime (2.0 mmol) was dissolved in 5 mL of anhydrous dichloromethane (DCM), and the solution was placed in a round bottom flask that had been pre-oven dried. A DCM solution of trifluoromethanesulfonic anhydride (2.0 mmol) was slowly added to the reaction mixture under nitrogen protection and the titration process was continued for 15 min. The reaction mixture was stirred at room temperature and the reaction process was monitored by thin layer chromatography (TLC) and gas chromatography-mass spectrometry (GC-MS) (see Table 1). Upon completion of the reaction, the reaction mixture was poured into crushed ice (100 mL), neutralized with 10% sodium bicarbonate (NaHCO3) solution (20 mL), and subsequently extracted with dichloromethane (3 × 15 mL). The organic phases were combined and purified by column chromatography using hexane-ethyl acetate (80:20, v/v) as eluent to afford the target product 1,2-benzisoxazol-6-ol. All the synthesized 1,2-benzisoxazole derivatives were characterized by GC-MS, nuclear magnetic resonance hydrogen spectroscopy (1H NMR) and carbon spectroscopy (13C NMR) as well as by elemental analysis, and the obtained data were validated by comparing them with real samples.

[1] Synthetic Communications, 2014, vol. 44, # 4, p. 547 - 555
[2] Tetrahedron Letters, 2006, vol. 47, # 47, p. 8247 - 8250
[3] Australian Journal of Chemistry, 1977, vol. 30, p. 1847 - 1850