Reaktion #574821

Reaktionsgleichung

sodium hydride

trans-3-hydroxy-6-cyano-3,4-dihydro-2,2-dimethyl-4-{1,2-dihydro-2-oxo-4-(2-t-butyldimethylsilyloxyethyl)-1-pyridinyl}-2H-benzo[b]pyran

water

→

6-cyano-2,2-dimethyl-4-(1,2-dihydro-2-oxo-4-vinyl-1-pyridinyl)-2H-benzo[b]pyran

Ausbeute 94.4%

Lösungsmittel

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigereacted
2. 2
   Temperaturunder reflux for one hour
3. 3
   Sonstigethe reaction
4. 4
   Extraktionthe reaction mixture is extracted with ether
5. 5
   WaschenThe organic layer is washed with saturated aqueous solution of sodium chloride
6. 6
   Trocknendried over anhydrous sodium sulfate
7. 7
   FiltrationThe inorganic matter is filtered off
8. 8
   Einengenthe filtrate is concentrated under reduced pressure
9. 9
   SonstigeThe residue thus obtained
10. 10
    Sonstigeis purified by silica gel column chromatography
11. 11
    workup.ADDITION1/4 mixture of ethyl acetate/methylene chloride as a developing solvent

Vorschrift

In 105 ml of anhydrous tetrahydrofuran, is dissolved 3.18 g of trans-3-hydroxy-6-cyano-3,4-dihydro-2,2-dimethyl-4-{1,2-dihydro-2-oxo-4-(2-t-butyldimethylsilyloxyethyl)-1-pyridinyl}-2H-benzo[b]pyran obtained in Example 23. Then, 0.28 g of 60% oily sodium hydride is added to the solution at room temperature and reacted under reflux for one hour. After stopping the reaction by adding water, the reaction mixture is extracted with ether. The organic layer is washed with saturated aqueous solution of sodium chloride and dried over anhydrous sodium sulfate. The inorganic matter is filtered off, and the filtrate is concentrated under reduced pressure. The residue thus obtained is purified by silica gel column chromatography using 1/4 mixture of ethyl acetate/methylene chloride as a developing solvent to obtain 2.01 g of 6-cyano-2,2-dimethyl-4-(1,2-dihydro-2-oxo-4-vinyl-1-pyridinyl)-2H-benzo[b]pyran.

Quelle