Reaktion #2254178

Reaktionsgleichung

Ethylene glycol

p-toluenesulfonic acid

2-brom-3-methyl-5-formylthiophene

→

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

Lösungsmittel

toluene

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturAfter 18 hours at reflux
2. 2
   Sonstigethe reaction is quenched with water
3. 3
   SonstigeThe organic phase is separated
4. 4
   Extraktionthe aqueous phase is extracted three times with ethyl acetate
5. 5
   TrocknenThe combined organic phases are dried over Na2SO4
6. 6
   Einengenconcentrated in vacuo
7. 7
   SonstigeThe crude product is purified on a semi-preparative HPLC

Vorschrift

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.

Quelle