反应 #1005975

反应方程式

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

BBr3

→

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

收率 40.0%

溶剂

CH2Cl2

CH2Cl2

反应条件

后处理

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

实验过程

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).

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