反应详情

A mixture of the product of Step 3 (0.98 g, 2.4 mmol), 2MKOH aq (3.6 ml, 7.2 ml) and 18-crown-6 ether (0.63 g, 0.24 mmol) in EtOH (50 ml) was refluxed for 30 h under N2. After cooling to room temperature the organic solvent was removed under reduced pressure and the residue was diluted to 5 ml with H2O, filtered and the filtrate was acidified to pH˜5 with 10% aqueous citric acid. The precipitate formed was filtered off, washed with H2O, small volume of EtOH, Et2O and dried in vacuo to give pure product as a deep yellow solid (0.89 g, 93%). 1H NMR (300 MHz, DMSO-d6) δ 7.65 (d, J=9.0 Hz, 1H), 7.3-7.5(m, 5H), 7.06-7.18(m, 5H), 6.31(m, 1H), 6.28(d, J=2.4 Hz, 1H), 3.92(m, 1H), 3.08(dd, J=7, 16 Hz, 2H), 2.72(dd, J=7 Hz, 16H), 2.48(s, 3H). LCMS, Rt=1.48 min, >99%, m/z (%): 395 (M+·, 100).

1. temperaturewas refluxed for 30 h under N2
2. customwas removed under reduced pressure
3. additionthe residue was diluted to 5 ml with H2O
4. filtrationfiltered
5. customThe precipitate formed
6. filtrationwas filtered off
7. washwashed with H2O, small volume of EtOH, Et2O
8. customdried in vacuo