反応 #52033

反応方程式

3,4-di-n-propoxythiophene

1,2,4-butanetriol

p-toluenesulphonic acid

→

2-(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-yl)ethanol

反応条件

後処理

1. 1
   workup.DISTILLATIONDuring this time, 5.89 g of distillate (substantially n-propanol) were collected
2. 2
   workup.ADDITIONThe cooled liquid was diluted with 50 ml of methylene chloride
3. 3
   洗浄washed
4. 4
   乾燥the organic phase was dried over Na2SO4
5. 5
   ろ過After filtering
6. 6
   その他evaporating the methylene chloride
7. 7
   workup.DISTILLATIONat 1 mbar, distillation
8. 8
   その他the fraction collected between 45 and 128° C. (1.63 g=19.4% of overall theoretical yield of transetherification products)

実験手順

9.06 g (45.2 mmol) of 3,4-di-n-propoxythiophene, 24.0 g (226 mmol) of 1,2,4-butanetriol and 0.09 g (0.5 mmol) of p-toluenesulphonic acid were heated to 150 to 160° C. (bath temperature) under N2 for 2 h. During this time, 5.89 g of distillate (substantially n-propanol) were collected. The cooled liquid was diluted with 50 ml of methylene chloride, washed to neutrality with water and the organic phase was dried over Na2SO4. After filtering and evaporating the methylene chloride at 1 mbar, distillation was then effected. According to 1H NMR spectroscopy, the fraction collected between 45 and 128° C. (1.63 g=19.4% of overall theoretical yield of transetherification products) consisted of approx. 81.5% of 2-(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-yl)ethanol, 6.5% of 3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepin-2-ylmethanol and 12% of 2,3,4,5-tetrahydrothieno[3,4-b][1,4]dioxocin-3-ol.

出典