Reaktion #528788

Reaktionsgleichung

p-toluenesulfonic acid

p-toluenesulfonic acid

Ethyl acetoacetate

tryptophol

→

1-methyl-1,3,4,9-tetrahydropyrano[3,4-b-]indole-1-acetic acid ethyl ester

Lösungsmittel

benzene

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturto reflux for thirty minutes
2. 2
   Temperaturrefluxing
3. 3
   Sonstigecontinued for 2 1/2 hours
4. 4
   SonstigeThe molecular sieves are collected
5. 5
   Waschenthe benzene solution washed successively with 5% sodium bicarbonate and water
6. 6
   Trocknendried over sodium sulfate
7. 7
   Sonstigeevaporated under reduced pressure to dryness
8. 8
   Sonstigeaffording an oil
9. 9
   WaschenElution with 5% ether in benzene

Vorschrift

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 (1.3g.) and about 5 g. of hydrated alkali-aluminum silicate (Molecular Sieves No. 4) are added. The mixture is subjected to reflux for thirty minutes, 600 mg. more of p-toluenesulfonic acid is added and refluxing continued for 2 1/2 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, γ maxCHCl3 1715 cm-1.

Quelle