反应详情

In a reaction vessel, water (200 ml) and 5-methyl-2-furylpropargylcarbinol (5 g) were charged, and the pH value was adjusted to 4 with an aqueous 1/3N NaOH solution and an aqueous 1/3N HCl solution. The temperature was elevated to 100° C. to reflux, and the mixture was stirred under reflux for 16 hours while maintaining the pH value of 3.8 to 4.1 by the addition of an aqueous 1/3N NaOH solution and an aqueous 1/3N HCl solution. Then, the pH value was adjusted to 8.0 with an aqueous 1/3N NaOH solution, and stirring under reflux was continued for 4 hours while maintaining the pH value of 7.5 to 8.0 by the addition of an aqueous 1/3N NaOH solution and an aqueous 1/3N HCl solution. After cooling, sodium chloride (70 g) was added, and the mixture was extracted with toluene (100 ml) four times. The extract was concentrated at 60° C. under reduced pressure to remove toluene, whereby an oily substance (4.7 g) was obtained. The crude product was purified by column chromatography with silica gel (60 g) (developing solvent, ethyl acetate-n-hexane (1:2 by volume)) to obtain 2-propargyl-3-methyl-4-hydroxy-2-cyclopentenone (3.4 g). Yield, 68%.

1. customwas elevated to 100° C.
2. temperatureto reflux
3. temperatureunder reflux for 16 hours
4. temperaturewhile maintaining the pH value of 3.8 to 4.1
5. stirringstirring
6. temperatureunder reflux
7. temperaturewhile maintaining the pH value of 7.5 to 8.0
8. temperatureAfter cooling
9. extractionthe mixture was extracted with toluene (100 ml) four times
10. concentrationThe extract was concentrated at 60° C. under reduced pressure
11. customto remove toluene, whereby an oily substance (4.7 g)
12. customwas obtained
13. customThe crude product was purified by column chromatography with silica gel (60 g) (developing solvent, ethyl acetate-n-hexane (1:2 by volume))