Reaktion #709253

Reaktionsgleichung

DBN

1,5-diazabicyclo[4.3.0]non-5-ene

4,5-dichloro-6-methoxy-3-oxo-2-propylbenzofuran

methyl vinyl ketone

→

1,2-Dichloro-3-methoxy-8-oxo-5a-propyl-5a,6,7,8-tetrahydrodibenzofuran

Lösungsmittel

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONwas added
2. 2
   SonstigeThe THF was evaporated in vacuo
3. 3
   workup.DISSOLUTIONthe residual oil dissolved in ether
4. 4
   Waschenethyl acetate, washed with water
5. 5
   Trocknendried over MgSO4
6. 6
   Sonstigeevaporated in vacuo
7. 7
   workup.DISSOLUTIONwas dissolved in ethanol (10 ml)
8. 8
   workup.ADDITIONwater (5 ml), treated with 5% NaOH (1 ml)
9. 9
   Sonstigeprecipitation of 1,2-dichloro-3-methoxy-8-oxo-5a-propyl-5a,6,7,8,-tetrahydrodibenzofuran (0.6 g) which melted at 172°-173° C.

Vorschrift

A solution of 4,5-dichloro-6-methoxy-3-oxo-2-propylbenzofuran (0.785 g, 0.0029 mole) in tetrahydrofuran (THF) (8 ml) was warmed to 40° C. and treated with 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) (10 μl) and then with methyl vinyl ketone (2 ml) over a 10 minute period. The reaction mixture was heated at 55° C. for 1/2 hour during which time DBN (2 x 10 μl) was added. The THF was evaporated in vacuo, the residual oil dissolved in ether and ethyl acetate, washed with water, dried over MgSO4 and evaporated in vacuo. The residual oil consisting of 4,5-dichloro-6-methoxy-3-oxo-2-(3-oxobutyl)-2-propylbenzofuran (0.81 g) was dissolved in ethanol (10 ml) and water (5 ml), treated with 5% NaOH (1 ml) and stirred at 25° C. for 72 hours. Treatment of the reaction mixture with water (5 ml) caused precipitation of 1,2-dichloro-3-methoxy-8-oxo-5a-propyl-5a,6,7,8,-tetrahydrodibenzofuran (0.6 g) which melted at 172°-173° C.

Quelle