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Cefroxadine ( INN, trade names Oraspor and Cefthan-DS) is a
This undergoes fragmentation when treated with benzothiazole-2-thiol to give 2. Ozonolysis (reductive work-up) cleaves the olefinic linkage and the unsymmetrical disulfide moiety is converted to a tosyl thioester (3). The enol moiety is methylated with diazomethane, the six-membered ring is closed by reaction with 1,5-diazabicyclo .4.0ndec-5-ene (
cephalosporin
The cephalosporins (sg. ) are a class of β-lactam antibiotics originally derived from the fungus ''Acremonium'', which was previously known as ''Cephalosporium''.
Together with cephamycins, they constitute a subgroup of β-lactam antibiotics ...
antibiotic. It is structurally related to cefalexin
Cefalexin, also spelled cephalexin, is an antibiotic that can treat a number of bacterial infections. It kills gram-positive and some gram-negative bacteria by disrupting the growth of the bacterial cell wall. Cefalexin is a beta-lactam antibi ...
, 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 comparatively readily available phenoxymethylpenicillin sulfoxide benzhydryl ester (1).
This undergoes fragmentation when treated with benzothiazole-2-thiol to give 2. Ozonolysis (reductive work-up) cleaves the olefinic linkage and the unsymmetrical disulfide moiety is converted to a tosyl thioester (3). The enol moiety is methylated with diazomethane, the six-membered ring is closed by reaction with 1,5-diazabicyclo .4.0ndec-5-ene (DBU
The decibel (symbol: dB) is a relative unit of measurement equal to one tenth of a bel (B). It expresses the ratio of two values of a Power, root-power, and field quantities, power or root-power quantity on a logarithmic scale. Two signals whose ...
), and the ester protection is removed with trifluoroacetic acid to give 4. The amide side chain is removed by the usual PCl5/dimethylaniline
''N'',''N''-Dimethylaniline (DMA) is an organic chemical compound, a substituted derivative of aniline. It consists of a tertiary amine, featuring dimethylamino group attached to a phenyl group. This oily liquid is colourless when pure, but comm ...
sequence followed by reamidation with the appropriate acid chloride to give cefroxadine (5).
See also
* CefachlorReferences