反应 #345760

反应方程式

2-phenyl-4-(β-hydroxyethyl)thiazole

ethyl propionylacetate

p-toluene-sulfonic acid hydrate

→

ethyl 6,7-dihydro-4-ethyl-2-phenyl-4H-pyrano[4,3-d]thiazole-4- acetate

溶剂

toluene

反应条件

后处理

1. 1
   温度is heated
2. 2
   温度at reflux temperature
3. 3
   其他with water separation
4. 4
   workup.ADDITIONAdditional ethyl propionylacetate (6 g) and p-toluenesulfonic acid hydrate is added
5. 5
   温度refluxing
6. 6
   workup.WAITis continued for 24 hr
7. 7
   其他The mixture is evaporated under reduced pressure
8. 8
   其他the residue is triturated with petroleum ether
9. 9
   workup.DISSOLUTIONThe residue is dissolved in a mixture of aqueous sodium bicarbonate solution and ether
10. 10
    其他The organic solution is separated
11. 11
    干燥dried over sodium sulfate
12. 12
    其他evaporated under reduced pressure

实验过程

A mixture of the starting material of formula II, 2-phenyl-4-(β-hydroxyethyl)thiazole (30.8 g, 0.15 mole, described in Example 1), ethyl propionylacetate (28.8 g, 0.2 mole) and p-toluene-sulfonic acid hydrate (0.25 mole) in toluene (1200 ml) is heated at reflux temperature, with water separation, for 17 hr. Additional ethyl propionylacetate (6 g) and p-toluenesulfonic acid hydrate is added and refluxing is continued for 24 hr. The mixture is evaporated under reduced pressure and the residue is triturated with petroleum ether. The residue is dissolved in a mixture of aqueous sodium bicarbonate solution and ether. The organic solution is separated, dried over sodium sulfate and evaporated under reduced pressure to give ethyl 6,7-dihydro-4-ethyl-2-phenyl-4H-pyrano[4,3-d]thiazole-4- acetate (IV, R1 = H, R2 = CH2CH3, A= COOCH2CH3 and n= 1).

来源