Reacción #81416

Ecuación de reacción

hydrochloric acid

4,4'-dimethylbenzophenone

potassium t-butoxide

diethyl succinate

→

4,4-Di(4-tolyl)-but-3-enoic acid

Disolventes

t-butanol

water

Condiciones de reacción

Tratamiento posterior

1. 1
   OtroTo a 500 mL round-bottomed flask equipped with condenser and nitrogen inlet
2. 2
   TemperaturaThe reaction was refluxed for 18 hours
3. 3
   Temperaturacooled
4. 4
   Extracciónextracted with ethyl acetate
5. 5
   SecadoThe organic layer was dried over sodium sulfate
6. 6
   Otroevaporated
7. 7
   workup.ADDITIONIt was then treated with 70 mL 48% hydrobromic acid
8. 8
   Temperaturarefluxed for 36 hours
9. 9
   TemperaturaThe reaction was cooled
10. 10
    Otropartitioned between water and ethyl acetate
11. 11
    Lavadothe combined organic layers washed with water and brine
12. 12
    Secadodried over sodium sulfate
13. 13
    Otroevaporated
14. 14
    OtroThe residue was chromatographed on silica gel
15. 15
    Otroto afford the product as low melting solid, 25.0 grams (66%), Rf =0.25 in 5% methanol/methylene chloride on silica gel

Procedimiento

To a 500 mL round-bottomed flask equipped with condenser and nitrogen inlet were added 29.7 grams (141 mmol) 4,4'-dimethylbenzophenone and 141 mL t-butanol forming a solution, followed by 17.4 grams (155 mmol) potassium t-butoxide and 29.5 grams (170 mmol) diethyl succinate. The reaction was refluxed for 18 hours, cooled, and acidified with 6N hydrochloric acid, then poured into water and extracted with ethyl acetate. The organic layer was dried over sodium sulfate and evaporated, and the residue taken up in 200 mL glacial acetic acid. It was then treated with 70 mL 48% hydrobromic acid and refluxed for 36 hours. The reaction was cooled, partitioned between water and ethyl acetate, and the combined organic layers washed with water and brine, dried over sodium sulfate, and evaporated. The residue was chromatographed on silica gel using methylene chloride/methanol as eluant to afford the product as low melting solid, 25.0 grams (66%), Rf =0.25 in 5% methanol/methylene chloride on silica gel. This material was used directly in the next step.

Fuente