Reacción #2254178

Ecuación de reacción

Ethylene glycol

p-toluenesulfonic acid

2-brom-3-methyl-5-formylthiophene

→

2-(5-bromo-4-methyl-thiophen-2-yl)-[1,3]dioxolane

Disolventes

toluene

Condiciones de reacción

Tratamiento posterior

1. 1
   TemperaturaAfter 18 hours at reflux
2. 2
   Otrothe reaction is quenched with water
3. 3
   OtroThe organic phase is separated
4. 4
   Extracciónthe aqueous phase is extracted three times with ethyl acetate
5. 5
   SecadoThe combined organic phases are dried over Na2SO4
6. 6
   Concentraciónconcentrated in vacuo
7. 7
   OtroThe crude product is purified on a semi-preparative HPLC

Procedimiento

Ethylene glycol (2.18 ml) and p-toluenesulfonic acid (0.74 g) is added to a solution of 2-brom-3-methyl-5-formylthiophene (4.0 g) in toluene (98 ml) in a Dean-Stark apparatus. After 18 hours at reflux, the reaction is quenched with water. The organic phase is separated and the aqueous phase is extracted three times with ethyl acetate. The combined organic phases are dried over Na2SO4 and concentrated in vacuo. The crude product is purified on a semi-preparative HPLC to yield 2-(5-bromo-4-methyl-thiophen-2-yl)-[1,3]dioxolane (4.04 g) as a yellow oil. MS (HPLC/MS): 250 (MH+). Retention time: 4.02 min.

Fuente