Water → HCID 59389363, compound

Participants

Reaction Steps

The compound of Example 41 (4.53 g) was dissolved in dichloromethane (50 mL). The solution was kept at 0° C. and boron tribromide (21.6 mL, 1.0 mol/L dichloromethane solution) was added. The resulting mixture was stirred for 1 hour. Subsequently, water was added and the mixture was extracted three times with ethyl acetate. The organic layer was washed with saturated brine and dried over sodium sulfate. The solvent was evaporated under reduced pressure. The resulting solid product (4.29 g) was dissolved in ethanol (40 mL). To this solution, water (40 mL) and potassium hydroxide (4.10 g) were added and the mixture was stirred for 2 hours under reflux. This was followed by addition of water and concentrated hydrochloric acid to make the mixture acidic. The resulting mixture was extracted with three times with ethyl acetate and the organic layer was washed with saturated brine, dried over sodium sulfate and filtered. The solvent was evaporated under reduced pressure. The resulting solid product (3.58 g) was dissolved in ethanol (100 mL). To this solution, concentrated sulfuric acid (2 mL) was added and the mixture was refluxed for 7.5 hours. Subsequently, ethanol was evaporated under reduced pressure and the residue was extracted three times with ethyl acetate. The organic layer was washed with saturated brine and dried over sodium sulfate. The solvent was evaporated under reduced pressure to afford the title compound as a gray powder (2.88 g) (Process B).

Provenance & Evidence