تفاعل #1005975

معادلة التفاعل

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

BBr3

→

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

المردود 40.0%

المذيبات

CH2Cl2

CH2Cl2

ظروف التفاعل

المعالجة

1. 1
   درجة الحرارةwas cooled to −78° C.
2. 2
   أخرىquenched by the slow addition of 50 mL of H2O
3. 3
   درجة الحرارةUpon warming to room temperature the aqueous layer
4. 4
   استخلاصwas extracted with CH2Cl2
5. 5
   غسيلthe combined organic layers were washed with saturated aqueous NaHCO3, H2O, and saturated aqueous NaCl
6. 6
   تجفيفbefore being dried over MgSO4
7. 7
   أخرىRemoval of the solvents under reduced pressure
8. 8
   أخرىgave a green-brown solid which
9. 9
   أخرىupon recrystallization (Et2O/hexanes)

الإجراء التجريبي

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).

المصدر