반응 #96238

반응 방정식

N-bromosuccinimide

N-bromosuccinimide

t-butyl 2-bromo-3-methyl-7-phenylacetamido-3-cephem-4-carboxylate-1-oxide

→

t-butyl 2-bromo-3-bromomethyl-7-phenylacetamido-3-cephem-4-carboxylate-1-oxide

수율 26.2%

용매

dichloromethane

반응 조건

후처리

1. 1
   기타the orange colored solution was evaporated to dryness under vacuo at low temperature
2. 2
   기타The residue was chromatographed over silica gel
3. 3
   workup.ADDITIONa 72:1 mixture of methylene chloride and acetone
4. 4
   workup.ADDITIONa 49:1 mixture of the same components

실험 절차

3.05 g of N-bromosuccinimide were added portionwise over 1.75 hours to an ice-cold solution of 4.6 g of t-butyl 2-bromo-3-methyl-7-phenylacetamido-3-cephem-4-carboxylate-1-oxide in 350 ml of dichloromethane under the exposure to light of a tungsten lamp of 150 W. After the addition of N-bromosuccinimide was complete, the exposure was continued for one hour and the orange colored solution was evaporated to dryness under vacuo at low temperature. The residue was chromatographed over silica gel, using as initial eluent a 72:1 mixture of methylene chloride and acetone and then a 49:1 mixture of the same components to obtain 1.4 g of t-butyl 2-bromo-3-bromomethyl-7-phenylacetamido-3-cephem-4-carboxylate-1-oxide by evaporation to dryness of the suitable fractions.

출처