反应详情

The product (55.2 g) from step (i), in 2,6-lutidine (100 ml), was added to a solution of the product (118.5 g) from step (c) in 2,6-lutidine (400 ml). The reaction mixture was stirred for 1 hour and p-toluenesulfonic acid (9.0 g) was added and then refluxed with a Dean Stark trap for 17 hours. The reaction mixture was concentrated in vacuo and the residue was partitioned between 5% NaHCO3 and EtOAc. The organic layer was separated, dried and concentrated to get an oil which was chromatographed on silica gel, using hexane: EtOAc (85:15) as the eluant, to afford the title product (124.3 g) as an orange oil. 1H NMR consistent with the desired structure.

1. temperaturerefluxed with a Dean Stark trap for 17 hours
2. concentrationThe reaction mixture was concentrated in vacuo
3. customthe residue was partitioned between 5% NaHCO3 and EtOAc
4. customThe organic layer was separated
5. customdried
6. concentrationconcentrated
7. customto get an oil which
8. customwas chromatographed on silica gel