Cefroxadine
Cefroxadine is a cephalosporin antibiotic. It is structurally related to cefalexin, and both drugs share a similar spectrum of activity.
It is available in Italy.Synthesis
Cefroxadine can be prepared by several routes, including one in which the enol is methylated with diazomethane as a key step. A rather more involved route starts with compatively readily available phenoxymethylpenicillin sulfoxide benzhydryl ester.
This undergoes fragmentation when treated with benzothiazole-2-thiol to give 2. Ozonolysis cleaves the olefinic linkage and the unsymmetrical disulfide moiety is converted to a tosyl thioester. The enol moiety is methylated with diazomethane, the six-membered ring is closed by reaction with 1,5-diazabicycloundec-5-ene, and the ester protection is removed with trifluoroacetic acid to give 4. The amide side chain is removed by the usual PCl5/dimethylaniline sequence followed by reamidation with the appropriate acid chloride to give cefroxadine.
