Реакция #2254178

Уравнение реакции

Ethylene glycol

p-toluenesulfonic acid

2-brom-3-methyl-5-formylthiophene

→

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

Растворители

toluene

Условия реакции

Обработка

1. 1
   ТемператураAfter 18 hours at reflux
2. 2
   Другоеthe reaction is quenched with water
3. 3
   ДругоеThe organic phase is separated
4. 4
   Экстракцияthe aqueous phase is extracted three times with ethyl acetate
5. 5
   СушкаThe combined organic phases are dried over Na2SO4
6. 6
   Концентрированиеconcentrated in vacuo
7. 7
   ДругоеThe crude product is purified on a semi-preparative HPLC

Методика

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.

Источник