反应详情

温度

70 °C

A solution of 3.44 g (0.012 mole) of 2-butyl-1-(4-carboxybenzyl)-5-formylimidazole, 2.40 g (0.016 mole) of 1-butylhydantoin, 25.92 g (0.071 mole) of 25% tetramethylammonium hydroxide-in-methanol and 12 mL of water is heated with stirring with an oil bath (bath temperature 135°-150° C.), allowing the methanol to distill over. After ca. 1/2 hour, the pot temperature is ca. 115°-120° C. The temperature is maintained 115°-120° C. for 15 minutes. The reaction solution is cooled to 70° C. and 5.04 g (0.084 mole) of glacial acetic acid and then ca. 100 mL of water are added to precipitate the mixed cis (Z) and trans (E) isomers. Separation with 200 mL of methanol, cooling, and filtering off the least soluble (E) isomer. Recrystallization of the (E) isomer is effected by dissolution in 50% methanol-methylene chloride and concentration to remove methylene chloride. The separated pale yellow crystals are filtered; mp 287°-289° C.; tlc (2:10 MeOH--CHCl3), 1 spot, Rf 0.4; nmr (DMSO--d6), vinyl proton at δ 5.86 ppm; MS (CI) 425.1 (M+ +1).

1. distillationto distill over
2. customis ca. 115°-120° C
3. temperatureThe temperature is maintained 115°-120° C. for 15 minutes
4. customto precipitate the mixed cis (Z) and trans (E)
5. customSeparation with 200 mL of methanol
6. temperaturecooling
7. filtrationfiltering off the least soluble (E) isomer
8. customRecrystallization of the (E) isomer
9. dissolutionis effected by dissolution in 50% methanol-methylene chloride
10. concentrationconcentration
11. customto remove methylene chloride
12. filtrationThe separated pale yellow crystals are filtered