反応 #63758

反応方程式

sodium hydroxide

5-(trifluoromethyl)-2-benzimidazolethiol

2-chloromethyl-3-methylpyridine hydrochloride

→

5-(trifluoromethyl)benzimidazole

溶媒

—

alcohol

water

反応条件

後処理

1. 1
   温度while cooling
2. 2
   workup.WAITthe mixture is left
3. 3
   温度at reflux overnight
4. 4
   その他subsequently evaporated to dryness in vacuo
5. 5
   workup.DISSOLUTIONThe residue is dissolved in 950 ml of methylene chloride
6. 6
   洗浄The solution is washed firstly with 200 ml of 1.5N sodium hydroxide solution
7. 7
   乾燥dried over sodium sulphate
8. 8
   その他evaporated in vacuo
9. 9
   その他The crude product is purified on 100 g of silica gel with ethyl acetate/methylene chloride (1:1) as the elution agent
10. 10
    その他Crystallization from methylene chloride/petroleum ether

実験手順

6.54 g of 5-(trifluoromethyl)-2-benzimidazolethiol are suspended in 200 ml of alcohol and treated with 5.34 g of 2-chloromethyl-3-methylpyridine hydrochloride while cooling wlth ice. Thereafter. a solution of 2.4 g of sodium hydroxide in 100 ml of water is added dropwise thereto, the mixture is left to boil at reflux overnight and subsequently evaporated to dryness in vacuo. The residue is dissolved in 950 ml of methylene chloride. The solution is washed firstly with 200 ml of 1.5N sodium hydroxide solution and then 3 x with 250 ml of water. dried over sodium sulphate and evaporated in vacuo. The crude product is purified on 100 g of silica gel with ethyl acetate/methylene chloride (1:1) as the elution agent. Crystallization from methylene chloride/petroleum ether gives 2-[[3-methyl-2-pyridyl)methyl]thio]-5-(trifluoromethyl)benzimidazole of melting point 180°-182°.

出典