反応 #1005975

反応方程式

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

BBr3

→

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

収率 40.0%

溶媒

CH2Cl2

CH2Cl2

反応条件

後処理

1. 1
   温度was cooled to −78° C.
2. 2
   その他quenched by the slow addition of 50 mL of H2O
3. 3
   温度Upon warming to room temperature the aqueous layer
4. 4
   抽出was extracted with CH2Cl2
5. 5
   洗浄the combined organic layers were washed with saturated aqueous NaHCO3, H2O, and saturated aqueous NaCl
6. 6
   乾燥before being dried over MgSO4
7. 7
   その他Removal of the solvents under reduced pressure
8. 8
   その他gave a green-brown solid which
9. 9
   その他upon recrystallization (Et2O/hexanes)

実験手順

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).

出典