反应详情

Intermediate 22 (47.6 g, 0.122 mol) was dissolved in xylene (500 ml) and added p-Toluenesulphonic acid (46 g, 0.24 mol). This mixture was refluxed for 20 h under a dean-stark condenser. Xylene was removed and pH of the residue was adjusted to 9 using aq NaHCO3 solution. Work up (EtOAc/H2O) afforded the crude. Crude was purified by column on 60-120 mesh silicagel using a gradient mixture of EtOAc and Petether (10:90) as eluent to afford the titled compound (11 g) as brown solid.

1. temperatureThis mixture was refluxed for 20 h under a dean-stark condenser
2. customXylene was removed
3. customWork up (EtOAc/H2O) afforded the crude
4. customCrude was purified by column on 60-120 mesh silicagel
5. additiona gradient mixture of EtOAc and Petether (10:90) as eluent