反应详情

To a solution of 8 (300 mg, 0.9 mmol) in MeOH (10 mL) was added 1 N NaOH (10 mL) and the mixture was stirred under N2 at room temperature for 16 h. TLC showed the disappearance of the starting material (Rf=0.56) and one major spot at the origin (MeOH/CHCl3 1:5). The reaction mixture was evaporated to dryness under reduced pressure. The residue was dissolved in water (10 mL), the resulting solution was cooled in an ice bath, and the pH was adjusted to 3-4 with dropwise addition of 1 N HCl. The resulting suspension was frozen in a dry ice-acetone bath, thawed to 4-5° C. in the refrigerator, and filtered. The residue was washed with a small amount of cold water and dried in vacuum using P2O5 to afford 254 mg of 9 as white powder. 1H NMR (DMSO-d6): δ 1.89-1.96 (m, 2H), 2.49-2.55 (t, J=7.2 Hz, 2H), 2.80-2.84 (t, J=7.2 Hz, 2H), 5.88 (s, 1H), 5.98 (s, 2H), 6.92-6.93 (d, J=3.6 Hz, 1H), 7.55-7.56 (d, J=3.6 Hz, 1H), 10.14 (s, 1H), 10.83 (s, 1H) 12.86 (br, 1H).

1. customThe reaction mixture was evaporated to dryness under reduced pressure
2. dissolutionThe residue was dissolved in water (10 mL)
3. temperaturethe resulting solution was cooled in an ice bath
4. additionthe pH was adjusted to 3-4 with dropwise addition of 1 N HCl
5. temperatureThe resulting suspension was frozen in a dry ice-acetone bath
6. customthawed to 4-5° C. in the refrigerator
7. filtrationfiltered
8. washThe residue was washed with a small amount of cold water
9. customdried in vacuum