反応 #2254178

反応方程式

Ethylene glycol

p-toluenesulfonic acid

2-brom-3-methyl-5-formylthiophene

→

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

溶媒

toluene

反応条件

後処理

1. 1
   温度After 18 hours at reflux
2. 2
   その他the reaction is quenched with water
3. 3
   その他The organic phase is separated
4. 4
   抽出the aqueous phase is extracted three times with ethyl acetate
5. 5
   乾燥The combined organic phases are dried over Na2SO4
6. 6
   濃縮concentrated in vacuo
7. 7
   その他The crude product is purified on a semi-preparative HPLC

実験手順

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.

出典