反应详情

温度

-7.5 °C

7-Amino-3-(1H-1,2,3-triazol-5-ylthiomethyl)-3-cephem-4-carboxylic acid (0.98 g) was suspended in methylene chloride (10 ml) and bis(trimethylsilyl)acetamide (2.53 g) was added to the suspension to give a solution. To the solution was added dropwise a solution of dichloroacetyl chloride (0.46 g) in methylene chloride (10 ml) at -30° C. The mixture was stirred at -10°0 to -15° C for 30 minutes and then concentrated under reduced pressure. To the residue was added ethyl acetate (50 ml) and water (30 ml) and the mixture was stirred and filtered. The ethyl acetate layer was separated from the filtrate and concentrated under reduced pressure to a half of volume. Water (30 ml) was added to the concentrated solution and the mixture was adjusted to pH 7.2 by adding aqueous sodium bicarbonate under cooling and stirring. The aqueous layer was separated from the mixture, adjusted to pH 6 with diluted hydrochloric acid, washed with ethyl acetate, adjusted to pH 2 with diluted hydrochloric acid and then extracted with ethyl acetate. The extract was washed with saturated aqueous sodium chloride, dried over magnesium sulfate and treated with activated charcoal powder. Ethyl acetate was distilled off from the solution under reduced pressure. The residue was pulverized by treating with ether and precipitates were collected by filtration to give 7-dichloroacetamido-3-(1H-1,2,3-triazol-5-ylthiomethyl)-3-cephem-4-carboxylic acid (0.56 g). The solvent was distilled off from the mother liquid under reduced pressure and the residue was pulverized by treating with diisopropyl ether. Precipitates were collected by filtration to give the same product (0.14 g). Total yield was 0.70 g.

1. customto give a solution
2. concentrationconcentrated under reduced pressure
3. additionTo the residue was added ethyl acetate (50 ml) and water (30 ml)
4. stirringthe mixture was stirred
5. filtrationfiltered
6. customThe ethyl acetate layer was separated from the filtrate
7. concentrationconcentrated under reduced pressure to a half of volume
8. additionWater (30 ml) was added to the concentrated solution
9. additionby adding aqueous sodium bicarbonate
10. temperatureunder cooling
11. stirringstirring
12. customThe aqueous layer was separated from the mixture
13. washwashed with ethyl acetate
14. extractionextracted with ethyl acetate
15. washThe extract was washed with saturated aqueous sodium chloride
16. dry with materialdried over magnesium sulfate
17. additiontreated with activated charcoal powder
18. distillationEthyl acetate was distilled off from the solution under reduced pressure
19. additionby treating with ether
20. customprecipitates
21. filtrationwere collected by filtration