Реакция #63758

Уравнение реакции

sodium hydroxide

5-(trifluoromethyl)-2-benzimidazolethiol

2-chloromethyl-3-methylpyridine hydrochloride

→

5-(trifluoromethyl)benzimidazole

Растворители

—

alcohol

water

Условия реакции

Обработка

1. 1
   Температураwhile cooling
2. 2
   workup.WAITthe mixture is left
3. 3
   Температураat reflux overnight
4. 4
   Другоеsubsequently evaporated to dryness in vacuo
5. 5
   workup.DISSOLUTIONThe residue is dissolved in 950 ml of methylene chloride
6. 6
   ПромывкаThe solution is washed firstly with 200 ml of 1.5N sodium hydroxide solution
7. 7
   Сушкаdried over sodium sulphate
8. 8
   Другоеevaporated in vacuo
9. 9
   ДругоеThe crude product is purified on 100 g of silica gel with ethyl acetate/methylene chloride (1:1) as the elution agent
10. 10
    ДругоеCrystallization from methylene chloride/petroleum ether

Методика

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°.

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