反应详情

The acetaldehyde intermediate (4) (2.1 g, 10 mmol) was taken up in tetrahydrofuran (200 mL), and water (0.5 mL) and concentrated hydrochloric acid (1.0 mL) were added. The solution was heated at reflux for 5 hrs., then diluted with water (20 mL) and evaporated at reduced pressure to remove most of the tetrahydrofuran. The residual aqueous solution was extracted with ether (3×200 mL), and the combined ether extracts were successively washed with saturated sodium bicarbonate solution (20 mL), brine (50 mL), then dried and concentrated to give a semisolid. Recrystallization from benzene hexane provided 1.0 g (52.1%) of compound (5). mp 86°-91° C., 1H NMR (CDCl3) δ7.04-6.78 (m, 1H), 6.12-5.84 (m, 1H), 2.60-1.0 (m, 11H), 2.16 (s, 3H); mass spectrum, m/z 192 (M+).

1. temperatureThe solution was heated
2. temperatureat reflux for 5 hrs
3. customevaporated at reduced pressure
4. customto remove most of the tetrahydrofuran
5. extractionThe residual aqueous solution was extracted with ether (3×200 mL)
6. washthe combined ether extracts were successively washed with saturated sodium bicarbonate solution (20 mL), brine (50 mL)
7. customdried
8. concentrationconcentrated
9. customto give a semisolid
10. customRecrystallization from benzene hexane