反应详情

A solution of 1.09 g (3.3 mmol) of rac-5-[6-[(tetrahydro-2H-pyran-2-yl)oxy]-1-hexynyl]-2H-1-benzopyran-2-one (preceding example) and 1.8 mL (7.9 mmol) of 25% methanolic sodium methoxide in 5 mL of methanol was stirred and refluxed for 24 hr and then concentrated under reduced pressure. The residue was treated with 1N hydrochloric acid and worked-up with ethyl acetate in the usual manner (the organic extracts were additionally washed with saturated aqueous sodium bicarbonate). The residue was purified by flash chromatography on silica gel, eluting with 2:1 hexane-ether. There was obtained 0.7 g (59%) of rac-(E)-3-[2-hydroxy-6-[6-[(tetrahydro-2H-pyran-2-yl)oxy]-1-hexynyl]phenyl]-2-propenoic acid methyl ester as a yellow oil. Trituration of a sample prepared in this way with hexane gave a colorless solid, mp 66°-67.5° C.

1. temperaturerefluxed for 24 hr
2. concentrationconcentrated under reduced pressure
3. additionThe residue was treated with 1N hydrochloric acid
4. washwere additionally washed with saturated aqueous sodium bicarbonate)
5. customThe residue was purified by flash chromatography on silica gel
6. washeluting with 2:1 hexane-ether