反应详情

123 mg of tri-n-propylchlorosilane were added to a suspension of 312 mg of 7-benzamido-2-bromo-3-bromomethyl-3-cephem-4-carboxylic acid-1-oxide (prepared by the process of Step D of Example 1) in 25 ml of 1,2-dichloroethane under a nitrogen atmosphere and then a solution of 64 mg of triethyl-amine in 4 ml of 1,2-dichloroethane was dropwise added over 15 minutes under cooling in an ice-bath. The clear, slightly yellow colored solution was stirred for two hours at room temperature and after removal of the solvent under vacuo, 7 ml of diethyl ether was added. The obtained suspension was centrifuged and the clear liquid layer was separated and evaporated to dryness under vacuo. The residue was kept at a pressure of 0.5 mm of mercury for half an hour to obtain 210 mg of tri-n-propylsilyl 7-benzamido-2-bromo-3-bromomethyl-3-cephem-4-carboxylate-1-oxide having the following characteristics:

1. temperatureunder cooling in an ice-bath
2. customafter removal of the solvent under vacuo, 7 ml of diethyl ether
3. additionwas added
4. customthe clear liquid layer was separated
5. customevaporated to dryness under vacuo
6. waitThe residue was kept at a pressure of 0.5 mm of mercury for half an hour