反应详情

7-Amino-3-(1-methyl-1H-tetrazol-5-ylthiomethyl)-3-cephem-4-carboxylic acid (3.28 g) was suspended in a mixture (60 ml) of water and acetone (1:1) and sodium bicarbonate was added to the suspension little by little to give a solution. Dichloroacetyl chloride (3 g) was added dropwise to the solution at -5° C under stirring and the mixture was stirred at the same temperature for 30 minutes. Ethyl acetate (50 ml) was added to the reaction mixture and the mixture was adjusted to pH 2 with diluted hydrochloric acid under stirring and filtered. The ethyl acetate layer was separated from the filtrate, washed with saturated aqueous sodium chloride, dried over magnesium sulfate and then treated with activated charcoal powder. Ethyl acetate was distilled off from the solution under reduced pressure. Ether was added to the residue and the mixture was stirred overnight. Precipitates were collected by filtration to give pale yellow powder of 7-dichloroacetamido-3-(1-methyl-1H-tetrazol-5-ylthiomethyl)-3-cephem-4-carboxylic acid (1.5 g).

1. additionwas added to the suspension little by little
2. customto give a solution
3. stirringthe mixture was stirred at the same temperature for 30 minutes
4. stirringunder stirring
5. filtrationfiltered
6. customThe ethyl acetate layer was separated from the filtrate
7. washwashed with saturated aqueous sodium chloride
8. dry with materialdried over magnesium sulfate
9. additiontreated with activated charcoal powder
10. distillationEthyl acetate was distilled off from the solution under reduced pressure
11. additionEther was added to the residue
12. stirringthe mixture was stirred overnight
13. customPrecipitates
14. filtrationwere collected by filtration