反应详情

A 250-mL Parr reactor bottle was purged with nitrogen and charged with platinum oxide (200 mg), 251a (2.00 g, 6.78 mmol), ethyl acetate (30 mL) and ethanol (30 mL). The bottle was attached to a Parr hydrogenator, evacuated, charged with hydrogen gas to a pressure of 50 psi and shaken for 20 h. After this time, the hydrogen was evacuated, and nitrogen was charged into the bottle. Celite 521 (10.0 g) was added, and the mixture was filtered through a pad of Celite 521. The filter cake was washed with methanol (2×50 mL), and the combined filtrates were concentrated to dryness under reduced pressure to afford a 100% yield (2.01 g) of 251b as a white solid: mp 83-84° C.; 1H NMR (500 MHz, DMSO-d6) d 7.53 (d, 1H, J=3.0 Hz), 7.04 (dd, 1H, J=9.0, 3.0 Hz), 6.41 (d, 1H, J=9.0 Hz), 5.32 (br s, 2H), 4.21 (t, 2H, J=6.5 Hz), 3.75 (t, 2H, J=6.5 Hz), 3.25 (m, 1H), 1.37 (s, 9H); MS (ESI+) m/z 266.2 (M+H).

1. customA 250-mL Parr reactor bottle was purged with nitrogen
2. customevacuated
3. additioncharged with hydrogen gas to a pressure of 50 psi
4. customAfter this time, the hydrogen was evacuated
5. additionnitrogen was charged into the bottle
6. additionCelite 521 (10.0 g) was added
7. filtrationthe mixture was filtered through a pad of Celite 521
8. washThe filter cake was washed with methanol (2×50 mL)
9. concentrationthe combined filtrates were concentrated to dryness under reduced pressure