Reaktion #54104

Reaktionsgleichung

NaBH4

(5-Bromo-2-hydroxy-phenyl)-phenyl-methanone

(5-bromo-2-hydroxy-phenyl)-phenyl-methanone

→

19

Ausbeute 98.0%

4-bromo-2-(hydroxy-phenyl-methyl)-phenol

Ausbeute 98.0%

Lösungsmittel

MeOH

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigewas evaporated
2. 2
   ExtraktionThe aq. layer was extracted with Et2O
3. 3
   Waschenfractions were washed twice with water
4. 4
   Trocknendried over Na2SO4
5. 5
   Sonstigeevaporated

Vorschrift

1.02 g (27 mmol, 3.9 eqv) NaBH4 was added cautiously at rt to a solution of 1.92 g (6.9 mmol) (5-Bromo-2-hydroxy-phenyl)-phenyl-methanone (18) in 70 ml dry MeOH. After stirring this solution for 2 h at rt the solvent was evaporated and the residue was taken up in 70 ml water and 70 ml Et2O. The aq. layer was extracted with Et2O and the comb. org. fractions were washed twice with water, dried over Na2SO4 and evaporated. Column chromatography (Hexanes/EtOAc (1+1)) yielded 1.88 g (6.7 mmol, 98%) 19 as a white solid: Rf (Hexanes/EtOAc (1+1)) 0.57; mp 96-97° C.; 1H NMR (500 MHz, CDCl3) δ 2.76 (d, 1H, J=3.15 Hz), 5.98 (d, 1H, J=3.00 Hz), 6.79 (d, 1H, J=8.67 Hz), 6.98 (dd, 1H, J1=2.21 Hz, J2=0.47 Hz), 7.28 (dd, 1H, J1=8.67 Hz, J2=2.36 Hz), 7.33-7.41 (m, 5H), 7.92 (s, 1H); LRMS (EI) m/z 278 (5), 276 (4), 262 (56), 261 (100), 260 (46), 259 (95), 181 (21), 180 (12), 153 (12), 152 (33), 77 (16), 76 (16), 63 (10); HRMS (EI) Calcd. for C13H11BrO2: 277.994241. Found: 277.993366.

Quelle