Hydroxylamine → 5-Bromo-3-isopropylbenzo[d]isoxazole

Participants

Reaction Conditions

Reaction Steps

1-(5-Bromo-2-hydroxyphenyl)-2-methylpropan-1-one (0.82 g, 3.37 mmol) was dissolved in EtOH (10 mL) then hydroxylamine (50% solution in water, 0.267 g, 4.05 mmol) was added followed by HOAc (1 drop). The mixture was heated to about 80° C. for about 2 h. The mixture was cooled then evaporated under reduced pressure to give an oil. Acetic anhydride (2 mL, 20 mmol) was added and the mixture was stirred for about 45 min at ambient temperature. The mixture was concentrated under reduced pressure then pyridine (7 mL) was added and then the mixture was heated to about 145° C. for about 3 h. The mixture was cooled, treated with 1 N HCl, and extracted with EtOAc. The organic extract was dried over MgSO4, filtered and evaporated to a residue that was then dissolved in DME (4 mL). Cesium carbonate (1.09 g, 3.35 mmol) was added and the mixture was heated at about 150° C. for about 30 min in the microwave. The mixture was evaporated and then purified by flash chromatography with 9:1 heptane/EtOAc to give the title compound (0.12 g, 15%): LC/MS (Table 1, Method a) Rt=3.33 min; MS m/z: 340.1 (M+H)+.

Provenance & Evidence