反应详情

Ethyl acetoacetate (23.4 g., 0.18 moles) is added to a solution of the starting material of formula II, tryptophol (10.0 g., 0.06 moles), in 200 ml. of benzene. After standing for 10 minutes, p-toluenesulfonic acid (1.3 g.) and about 5 g. of hydrated alkali-aluminum silicate (Molecular Sieves No. 4) are added. The mixture is subjected to reflux for 30 minutes, 600 mg. more of p-toluenesulfonic acid is added and refluxing continued for 21/2 hours. The molecular sieves are collected and the benzene solution washed successively with 5% sodium bicarbonate and water, dried over sodium sulfate, and evaporated under reduced pressure to dryness affording an oil. The oil is subjected to chromatography on silica gel. Elution with 5% ether in benzene yields the ester, 1-methyl-1,3,4,9-tetrahydropyrano[3,4-b-]indole-1-acetic acid ethyl ester, as an oil, νmaxCHCl3 1715 cm-1.

1. temperatureto reflux for 30 minutes
2. temperaturerefluxing
3. custom2 hours
4. customThe molecular sieves are collected
5. washthe benzene solution washed successively with 5% sodium bicarbonate and water
6. dry with materialdried over sodium sulfate
7. customevaporated under reduced pressure to dryness
8. customaffording an oil
9. washElution with 5% ether in benzene