Reaction #577199

Reaction equation

water

dimethyl succinate

Potassium t-butoxide

4,4′-difluorobenzophenone

→

3-methoxycarbonyl-3-butenoic acid

Solvents

toluene

toluene

toluene

Conditions

Workup

1. 1
   Otherequipped with a mechanical stirrer
2. 2
   TemperatureThe reaction mixture was heated at 70° C. for 4 hours
3. 3
   TemperatureAfter cooling to room temperature
4. 4
   ExtractionThe aqueous layer was extracted with diethyl ether (1×400 mL)
5. 5
   Otherto remove the neutral products
6. 6
   OtherA brownish-yellow oily solid was obtained from the aqueous layer
7. 7
   Extractionwas extracted with 3×300 mL of ethyl acetate
8. 8
   Washwashed with saturated NaCl solution (1×500 mL)
9. 9
   Dryingdried over anhydrous sodium sulfate
10. 10
    OtherRemoval of the solvent
11. 11
    Otherby rotary evaporation

Procedure

Potassium t-butoxide (68.8 g) was weighed into a reaction flask equipped with a mechanical stirrer, placed under a nitrogen atmosphere and 700 mL of toluene was added followed by 4,4′-difluorobenzophenone (100 g). The reaction mixture was stirred mechanically and heated to 70° C. A solution of dimethyl succinate (80 g) in 100 mL of toluene was added to the reaction mixture over a 60 minute period. The reaction mixture was heated at 70° C. for 4 hours. After cooling to room temperature, the reaction mixture was poured into 500 mL of water and the toluene layer discarded. The aqueous layer was extracted with diethyl ether (1×400 mL) to remove the neutral products, and then acidified the aqueous layer with concentrated HCl. A brownish-yellow oily solid was obtained from the aqueous layer, and was extracted with 3×300 mL of ethyl acetate. The organic layers were combined, washed with saturated NaCl solution (1×500 mL) and dried over anhydrous sodium sulfate. Removal of the solvent by rotary evaporation yielded 122 g of 4,4-di(4-fluorophenyl))-3-methoxycarbonyl-3-butenoic acid as a brownish oily solid. This material was not purified further but was used directly in the next step.

Source