反应详情

10 g of t-butyl 2-bromo-3-bromomethyl-7-formamido-3-cephem-4-carboxylate-1-oxide in 40 ml of trifluoroacetic acid were stirred for 15 minutes at room temperature and the solvent was removed by evaporation under vacuo. 25 ml of dichloromethane were added to the residue and evaporation to dryness was repeated. A 1:1 mixture of heptane and ether was added to the residue whereafter the slightly yellow crystals were vacuum filtered and were washed with the same solvent mixture to obtain 9.57 g of 2-bromo-3-bromomethyl-7-formamido-3-cephem-4-carboxylic acid-1-oxide having the following characteristics:

1. customthe solvent was removed by evaporation under vacuo
2. addition25 ml of dichloromethane were added to the residue and evaporation to dryness
3. additionA 1:1 mixture of heptane and ether
4. additionwas added to the residue whereafter the slightly yellow crystals
5. filtrationfiltered
6. washwere washed with the same solvent mixture