反应详情

A 100-mL single-neck round-bottomed flask equipped with a magnetic stirrer was charged with 238c (1.3 g, 6.25 mmol, 1.0 eq.) and THF (20 mL). At −78° C., to the solution was added lithium hexamethyldisilazane/THF (18.7 mL, 18.7 mmol, 3.0 eq.). It was then stirred at room temperature for 2 hrs. After the reaction was completed, saturated aqueous NH4Cl solution (30 mL) was added and the mixture was concentrated under reduced pressure. The residue was extracted with dichloromethane (3×50 mL) and the combined organic layer was evaporated under reduced pressure. The resulting residue was purified by silica-gel column chromatography eluting with 60:1 dichloromethane/methanol to afford 238d (585 mg, 53%) as a yellow solid. MS: [M+H]+ 177.3. 1H NMR (500 MHz, DMSO-d6) δ 7.38 (s, 1H), 5.82 (s, 1H), 4.13 (s, 2H), 3.86 (t, J=6.5 Hz, 2H), 2.73 (t, J=6.5 Hz, 2H), 191-1.88 (m, 2H), 1.75-1.73 (m, 2H).

1. customA 100-mL single-neck round-bottomed flask equipped with a magnetic stirrer
2. concentrationthe mixture was concentrated under reduced pressure
3. extractionThe residue was extracted with dichloromethane (3×50 mL)
4. customthe combined organic layer was evaporated under reduced pressure
5. customThe resulting residue was purified by silica-gel column chromatography
6. washeluting with 60:1 dichloromethane/methanol