Reacción #579402

Ecuación de reacción

2-methylthiophene

methacrylic acid

→

product

Rendimiento 46.0%

2,5-dimethyl-4,5-dihydrocyclopenta[b]thiophen-6-one

Rendimiento 46.0%

Disolventes

dichloromethane

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.DISSOLUTIONhad completely dissolved
2. 2
   ExtracciónThe aqueous phase was extracted twice with 400 ml each time of a dichloromethane/hexane solvent mixture (30 parts by volume/70 parts by volume)
3. 3
   LavadoThe combined organic phases were washed with a saturated aqueous solution of sodium hydrogencarbonate
4. 4
   Secadodried over magnesium sulfate
5. 5
   OtroAfter removal of the solvents
6. 6
   Otroon a rotary evaporator
7. 7
   Otro136 g of crude product were obtained
8. 8
   workup.DISTILLATIONThe distillation of the crude product (90° C., 0.1 torr)

Procedimiento

A solution of 100 g of 2-methylthiophene (1.02 mol) and 104 ml of methacrylic acid (1.22 mol) in 200 ml of dichloromethane was added dropwise within 30 minutes at 80° C. to 1000 g of super-PPA. Afterwards, the reaction mixture was stirred at 80° C. for 3 hours. The dark red mixture was poured into 1000 g of crushed ice and stirred until the polyphosphoric acid had completely dissolved. The aqueous phase was extracted twice with 400 ml each time of a dichloromethane/hexane solvent mixture (30 parts by volume/70 parts by volume). The combined organic phases were washed with a saturated aqueous solution of sodium hydrogencarbonate and dried over magnesium sulfate. After removal of the solvents on a rotary evaporator, 136 g of crude product were obtained. The distillation of the crude product (90° C., 0.1 torr) gave 76 g (46%) of product.

Fuente