Reacción #63752

Ecuación de reacción

sodium hydroxide

5H-1,3-dioxolo[4,5-f]benzimidazole-6-thiol

2-chloromethyl-4-methoxy-3,5-dimethylpyridine hydrochloride

→

6-[[(4-methoxy-3,5-dimethyl-2-pyridyl)methyl]thio]-5H-1,3-dioxolo[4,5-f]benzimidazole

Disolventes

—

alcohol

water

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturawhile cooling with ice
2. 2
   workup.WAITthe mixture is left
3. 3
   Temperaturaat reflux overnight
4. 4
   Otrosubsequently evaporated to dryness in vacuo
5. 5
   workup.DISSOLUTIONThe residue is dissolved in 1000 ml of methylene chloride
6. 6
   LavadoThe solution is washed firstly with 500 ml of 1.5N sodium hydroxide solution
7. 7
   Secadowith 3×500 ml of water, dried over sodium sulphate
8. 8
   Otroevaporated in vacuo
9. 9
   OtroThe crude product is purified on 300 g of silica gel with ethyl acetate/methylene chloride (1:1) as the elution agent
10. 10
    OtroCrystallization from methylene chloride/petroleum ether

Procedimiento

14.8 g (76.7 mmol) of 5H-1,3-dioxolo[4,5-f]benzimidazole-6-thiol are suspended in 300 ml of alcohol and treated with 170 g (76.5 mmol) of 2-chloromethyl-4-methoxy-3,5-dimethylpyridine hydrochloride while cooling with ice. Thereafter, a solution of 6.0 g of sodium hydroxide in 150 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 1000 ml of methylene chloride. The solution is washed firstly with 500 ml of 1.5N sodium hydroxide solution and then with 3×500 ml of water, dried over sodium sulphate and evaporated in vacuo. The crude product is purified on 300 g of silica gel with ethyl acetate/methylene chloride (1:1) as the elution agent. Crystallization from methylene chloride/petroleum ether gives 6-[[(4-methoxy-3,5-dimethyl-2-pyridyl)methyl]thio]-5H-1,3-dioxolo[4,5-f]benzimidazole of melting point 178°-179°.

Fuente