反应详情

A solution of 1-(2-acetyl-3-hydroxyphenoxy)-2-hydroxy-3-m-cresyloxypropane (25.3 g) in diethyl oxalate (30 ml) was added to a suspension of sodium ethoxide, prepared from sodium (6.0 g) and ethanol (60 ml), in dry ether (400 ml). The mixture was heated under reflux for 1.5 hours; the brown residue was poured onto ice (200 g) and acidified with a solution of acetic acid (24 ml) in water (160 ml). The ether layer was separated after adding more water (200 ml) and the aqueous layer extracted with ether (3 × 50 ml), adding the extracts to the organic layer. The solvent was then removed and the residue dissolved in absolute ethanol (200 ml) to which hydrochloric acid (10 drops) was added. The solution was heated under reflux for 30 minutes and the solvent removed to give a viscous brown oil, which solidified on standing. The oily crystals were filtered off and after recrystallization from aqueous ethanol gave 1-(2-carbethoxy-chromon-5-yloxy)-2 -hydroxy-3-m-cresyloxypropane (8.2 g) as a white solid, m.p. 72°-74°.

1. temperatureThe mixture was heated
2. temperatureunder reflux for 1.5 hours
3. additionthe brown residue was poured onto ice (200 g)
4. customThe ether layer was separated
5. additionafter adding more water (200 ml)
6. extractionthe aqueous layer extracted with ether (3 × 50 ml)
7. additionadding the extracts to the organic layer
8. customThe solvent was then removed
9. dissolutionthe residue dissolved in absolute ethanol (200 ml) to which hydrochloric acid (10 drops)
10. additionwas added
11. temperatureThe solution was heated
12. temperatureunder reflux for 30 minutes
13. customthe solvent removed
14. customto give a viscous brown oil, which
15. filtrationThe oily crystals were filtered off
16. customafter recrystallization from aqueous ethanol