Реакция #1005975

Уравнение реакции

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

BBr3

→

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

Выход 40.0%

Растворители

CH2Cl2

CH2Cl2

Условия реакции

Обработка

1. 1
   Температураwas cooled to −78° C.
2. 2
   Другоеquenched by the slow addition of 50 mL of H2O
3. 3
   ТемператураUpon warming to room temperature the aqueous layer
4. 4
   Экстракцияwas extracted with CH2Cl2
5. 5
   Промывкаthe combined organic layers were washed with saturated aqueous NaHCO3, H2O, and saturated aqueous NaCl
6. 6
   Сушкаbefore being dried over MgSO4
7. 7
   ДругоеRemoval of the solvents under reduced pressure
8. 8
   Другоеgave a green-brown solid which
9. 9
   Другоеupon recrystallization (Et2O/hexanes)

Методика

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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