反应详情

A mixture of dibenzoylmethane (4.48 g), methyl acrylate (1.8 ml), potassium t-butoxide (0.23 g) and N,N-dimethylformamide (40 ml) was stirred at room temperature overnight. The reaction mixture was poured into dilute hydrochloric acid, and the mixture was extracted with ethyl acetate. The ethyl acetate layer was washed with saturated brine, dried (MgSO4) and concentrated. The residue was subjected to silica gel column chromatography, and a colorless oil was obtained from a fraction eluted with ethyl acetate-hexane (1:9, volume ratio). A mixture of the obtained colorless oil, hydroxylamine hydrochloride (1.00 g) and isopropyl alcohol (50 ml) was refluxed for 6 hr. The reaction mixture was poured into dilute hydrochloric acid, and the mixture was extracted with ethyl acetate. The ethyl acetate layer was washed with saturated brine, dried (MgSO4) and concentrated to give a colorless oil. A mixture of the obtained colorless oil, 2N sodium hydroxide (20 ml) and methanol (30 ml) was stirred at room temperature for 2 hr. The reaction mixture was acidified with dilute hydrochloric acid and extracted with ethyl acetate. The ethyl acetate layer was washed with saturated brine, dried (MgSO4) and concentrated. The obtained colorless crystals were filtrated to give 3-[3,5-diphenyl-4-isoxazolyl]propionic acid (1.91 g, yield 33%). The crystals were recrystallized from ethanol. melting point: 152–153° C.

1. extractionthe mixture was extracted with ethyl acetate
2. washThe ethyl acetate layer was washed with saturated brine
3. dry with materialdried (MgSO4)
4. concentrationconcentrated
5. customa colorless oil was obtained from a fraction
6. washeluted with ethyl acetate-hexane (1:9, volume ratio)
7. additionA mixture of the obtained colorless oil, hydroxylamine hydrochloride (1.00 g) and isopropyl alcohol (50 ml)
8. temperaturewas refluxed for 6 hr
9. additionThe reaction mixture was poured into dilute hydrochloric acid
10. extractionthe mixture was extracted with ethyl acetate
11. washThe ethyl acetate layer was washed with saturated brine
12. dry with materialdried (MgSO4)
13. concentrationconcentrated
14. customto give a colorless oil
15. stirringwas stirred at room temperature for 2 hr
16. extractionextracted with ethyl acetate
17. washThe ethyl acetate layer was washed with saturated brine
18. dry with materialdried (MgSO4)
19. concentrationconcentrated
20. filtrationThe obtained colorless crystals were filtrated