Reaktion #579401

Reaktionsgleichung

water

2-methylthiophene

methacrylic acid

Eaton's reagent

→

product

Ausbeute 76.0%

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

Ausbeute 76.0%

Lösungsmittel

dichloromethane

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigewas between 78° C. and 83° C
2. 2
   workup.ADDITIONOn completion of addition
3. 3
   SonstigeThe organic phase was removed
4. 4
   Trocknendried over magnesium sulfate
5. 5
   workup.DISTILLATIONThe solvent was distilled off on a rotary evaporator
6. 6
   Sonstige263.5 g of crude product were obtained in a purity of 88.2%
7. 7
   workup.DISTILLATIONA portion of the crude product (79 g) was distilled (92° C., 0.02 torr)

Vorschrift

A mixture of 150 g of 2-methylthiophene (1.5 mol) and 157.5 g of methacrylic acid (1.8 mol) was added within 30 minutes at about 80° C. to 1500 ml of Eaton's reagent, and the temperature was between 78° C. and 83° C. On completion of addition, the reaction mixture was stirred for a further 5 minutes and then gradually poured into a vigorously stirred mixture of 3000 ml of water and 500 ml of dichloromethane. The organic phase was removed and dried over magnesium sulfate. The solvent was distilled off on a rotary evaporator and 263.5 g of crude product were obtained in a purity of 88.2% according to GC-MS analysis. A portion of the crude product (79 g) was distilled (92° C., 0.02 torr). 56.5 g (76%) of product were obtained as a mixture of two isomers in a ratio of approx. 9:1 (thiophen-6-one: thiophen-4-one).

Quelle