Reaktion #1005975

Reaktionsgleichung

6-methoxy-2,2-dimethyl-thiochroman-4-one

BBr3

→

6-hydroxy-2,2-dimethylthiochroman-4-one

Ausbeute 40.0%

Lösungsmittel

CH2Cl2

CH2Cl2

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturwas cooled to −78° C.
2. 2
   Sonstigequenched by the slow addition of 50 mL of H2O
3. 3
   TemperaturUpon warming to room temperature the aqueous layer
4. 4
   Extraktionwas extracted with CH2Cl2
5. 5
   Waschenthe combined organic layers were washed with saturated aqueous NaHCO3, H2O, and saturated aqueous NaCl
6. 6
   Trocknenbefore being dried over MgSO4
7. 7
   SonstigeRemoval of the solvents under reduced pressure
8. 8
   Sonstigegave a green-brown solid which
9. 9
   Sonstigeupon recrystallization (Et2O/hexanes)

Vorschrift

To a solution of 6-methoxy-2,2-dimethyl-thiochroman-4-one (6.0 g, 27 mmol) in 50 mL CH2Cl2 cooled to −23° C. was added BBr3 (20.0 g, 80.0 mmol; 80.0 mL of a 1M solution in CH2Cl2) over a 20 minute period. After stirring for 5 hours at −23° C. the solution was cooled to −78° C. and quenched by the slow addition of 50 mL of H2O. Upon warming to room temperature the aqueous layer was extracted with CH2Cl2 and the combined organic layers were washed with saturated aqueous NaHCO3, H2O, and saturated aqueous NaCl before being dried over MgSO4. Removal of the solvents under reduced pressure gave a green-brown solid which upon recrystallization (Et2O/hexanes) afforded 2.25 g (40%) of 6-hydroxy-2,2-dimethylthiochroman-4-one as a light brown solid. 1H NMR (300 MHz, CDCl3) δ: 7.63 (1H, d, J=2.8 Hz), 7.15 (1H, d, J=8.5 Hz), 7.01 (1H, dd, J=2.8, 8.5 Hz), 2.87 (2H, s), 1.46 (6H, s).

Quelle