Réaction #2254178

Équation de réaction

Ethylene glycol

p-toluenesulfonic acid

2-brom-3-methyl-5-formylthiophene

→

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

Solvants

toluene

Conditions de réaction

Traitement

1. 1
   TempératureAfter 18 hours at reflux
2. 2
   Autrethe reaction is quenched with water
3. 3
   AutreThe organic phase is separated
4. 4
   Extractionthe aqueous phase is extracted three times with ethyl acetate
5. 5
   SéchageThe combined organic phases are dried over Na2SO4
6. 6
   Concentrationconcentrated in vacuo
7. 7
   AutreThe crude product is purified on a semi-preparative HPLC

Mode opératoire

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.

Source