反应详情

1-(3,5-Difluorobenzyl)-2-mercaptoimidazole (2.26 g, 0.010 mole) and chloroacetic acid (0.95 g, 0.010 mole) were dissolved in a mixture of dimethylformamide (10 ml) and water (0.5 ml), and potassium hydroxide (1.12 g, 0.020 mole) in water (10 ml) was added dropwise with stirring at ambient temperature over 30 minutes. Stirring at ambient temperature was continued for five hours. The solution was then diluted with water (10 ml) and acidified with concentrated hydrochloric acid. A trace of precipitate formed. The mixture was filtered and the pH of the filtrate was adjusted to 5.5 with concentrated ammonium hydroxide and the mixture was extracted with three portions of methylene chloride. Concentration of the combined extracts gave a clear, heavy oil which was triturated with boiling ether. A white crystalline solid formed which was filtered and recrystallized from ethyl acetate hexane to give 1.18 g (42% yield) of 2-(carboxymethylthio)-1-(3,5-difluorobenzyl)imidazole, mp 101°-103° C.

1. additionwas added dropwise
2. stirringStirring at ambient temperature
3. waitwas continued for five hours
4. customA trace of precipitate formed
5. filtrationThe mixture was filtered
6. extractionthe mixture was extracted with three portions of methylene chloride
7. customConcentration of the combined extracts gave a clear, heavy oil which
8. customwas triturated with boiling ether
9. customA white crystalline solid formed which
10. filtrationwas filtered
11. customrecrystallized from ethyl acetate hexane