反応 #70957

反応方程式

1,2-bis(2,5-dimethyl-3-thienyl)ethanedione

benzene

Potassium t-butoxide

benzene

→

25

収率 25.0%

3,4-bis(2,5-dimethyl-3-thienyl)cyclohexadiene

収率 25.0%

反応条件

後処理

1. 1
   温度The resulting orange solution was heated
2. 2
   温度to reflux
3. 3
   workup.STIRRINGThe reaction mixture was stirred
4. 4
   温度at reflux for 20 min, at which point the heating mantle
5. 5
   その他was removed
6. 6
   温度to cool to room temperature
7. 7
   その他The reaction was quenched by the addition of water (50 mL)
8. 8
   抽出extracted with Et2O (3×50 mL)
9. 9
   洗浄washed with brine
10. 10
    乾燥dried over MgSO4
11. 11
    ろ過filtered
12. 12
    その他The solvent was removed under reduced pressure
13. 13
    その他the residue was purified by column chromatography through silica (1:9 EtOAc:hexanes)

実験手順

Potassium t-butoxide (163 mg, 1.45 mmol) was added to a suspension of 1,4-butanebis(triphenylphosphonium)dibromide (537 mg, 0.725 mmol) in benzene (50 mL). The reaction was stirred for 45 min at room temperature. The resulting orange solution was heated to reflux and treated drop-wise with a solution of 1,2-bis(2,5-dimethyl-3-thienyl)ethanedione 23 (202 mg, 0.72 mmol) in benzene (25 mL). The reaction mixture was stirred at reflux for 20 min, at which point the heating mantle was removed and the reaction was allowed to cool to room temperature. The reaction was quenched by the addition of water (50 mL) and extracted with Et2O (3×50 mL). The organic extracts were combined, washed with brine, dried over MgSO4 and filtered. The solvent was removed under reduced pressure and the residue was purified by column chromatography through silica (1:9 EtOAc:hexanes) to yield 55 mg (25%) of 25 as a white solid. Mp=55-57° C. 1H NMR (CDCl3): δ=6.13 (s, 2H), 5.88 (m, 2H), 2.26 (m, 10H), 2.14 (s, 6H); 13C NMR (CDCl3) δ=137.8, 134.4, 133.9, 131.6, 127.4, 126.7, 22.7, 15.1, 14.0. MS (EI): m/z=300 (M+).

出典