反应详情

A mixture of 18 (from above), toluene (75 mL) and a crystal of p-toluenesulfonic acid monohydrate was refluxed with H2O removal (Dean-Stark trap) for 2 hr. The mixture was cooled to room temperature and stirred overnight. The mixture was washed with saturated NaHCO3 solution (25 mL), dried over Na2SO4, filtered and the solution concentrated under reduced pressure to give a brown oil. The crude product was absorbed onto silica gel using DCM and dry-loaded on a column of silica gel (60 g) packed in hexanes. The column was eluted with hexanes (300 mL), 0.4% MTBE/hexanes (500 mL), 0.8% MTBE/hexanes (500 mL) and 1% MTBE/hexanes (1000 mL). Product fractions were concentrated under reduced pressure to give 0.6 g of an inseparable mixture of 19 and 2-(benzyoxy)-2′-methoxybiphenyl as a colorless oil.

1. washThe mixture was washed with saturated NaHCO3 solution (25 mL)
2. dry with materialdried over Na2SO4
3. filtrationfiltered
4. concentrationthe solution concentrated under reduced pressure
5. customto give a brown oil
6. customThe crude product was absorbed onto silica gel
7. washThe column was eluted with hexanes (300 mL), 0.4% MTBE/hexanes (500 mL), 0.8% MTBE/hexanes (500 mL) and 1% MTBE/hexanes (1000 mL)
8. concentrationProduct fractions were concentrated under reduced pressure