Reacción #74933

Ecuación de reacción

hydrogen sulfide

phosphorus pentasulfide

hydrogen sulfide

sodium hydroxide

1,2-di-p-anisyl-4-p-tolylbutene-1,4-dione

→

2,3-Di-p-anisyl-5-p-tolylthiophene

Disolventes

ethanol

xylene

Condiciones de reacción

Tratamiento posterior

1. 1
   TemperaturaThe vessel was chilled with a Dry Ice-acetone bath
2. 2
   TemperaturaThe autoclave was then heated
3. 3
   TemperaturaAfter cooling the vessel
4. 4
   Otroto destroy unreacted phosphorus pentasulfide
5. 5
   OtroAfter removal of the ethanol there remained 70.5 g of crude product
6. 6
   OtroRecrystallization from ethanol-dioxane (70:30)
7. 7
   Otrogave 20 g (49.3%) of pure 2,3-di-p-anisyl-5-p-tolythiophene, m.p. 99°-102° C.

Procedimiento

In a 1-liter stainless steel autoclave equipped with stirrer were placed 40.6 g (0.105 mole) of 1,2-di-p-anisyl-4-p-tolylbutene-1,4-dione, 100 ml of xylene and 25 g (0.056 mole) of phosphorus pentasulfide. The vessel was chilled with a Dry Ice-acetone bath and charged with 130 g (3.81 moles) of hydrogen sulfide. The autoclave was then heated with stirring for 215 minutes at 158°-165° C. (1250-1360 psig). After cooling the vessel, the hydrogen sulfide was allowed to vent into a sodium hydroxide solution. The residue was treated with 150 ml of absolute ethanol to destroy unreacted phosphorus pentasulfide. After removal of the ethanol there remained 70.5 g of crude product. Recrystallization from ethanol-dioxane (70:30) gave 20 g (49.3%) of pure 2,3-di-p-anisyl-5-p-tolythiophene, m.p. 99°-102° C. and a second crop of 6.5 g (16.0%) m.p. 92°-96° C.

Fuente