[OH:1][C:2]1[CH:3]=[C:4]([CH:7]=[CH:8][CH:9]=1)[CH:5]=[O:6].[N+:10]([CH3:13])([O-:12])=[O:11].[F-].C([N+](CCCC)(CCCC)CCCC)CCC>O1CCCC1.C(OCC)(=O)C>[OH:6][CH:5]([C:4]1[CH:3]=[C:2]([OH:1])[CH:9]=[CH:8][CH:7]=1)[CH2:13][N+:10]([O-:12])=[O:11]Dissolve 3-hydroxybenzaldehyde (18.4 g, 15.07 mmol) in tetrahydrofuran (100 mL). Add nitromethane ((42 mL, 780 mmol), cool in an ice bath and add tetrabutylammonium fluoride (151 mL, 151 mmol, 1.0 M in tetrahydrofuran). Stir for 2 hours, dilute with ethyl acetate (200 mL), wash with water (3×500 mL) and saturated aqueous sodium chloride (200 mL). Extract the aqueous washes with diethyl ether (3×), wash with saturated aqueous sodium chloride, dry (magnesium sulfate), filter through a pad of silica gel, and concentrate. Suspend the residue in hot dichloromethane with 5% ethyl acetate, cool and filter solid. Purify filtrate using silica gel chromatography, eluting with 5:95 ethyl acetate:dichloromethane. Combine the solid from the dichloromethane tritutation with the purified filtrate to give the desired compound (24.88 g, 90% total yield).
Wird geladen…
