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Cefroxadine (
This undergoes fragmentation when treated with benzothiazole-2-thiol to give 2.
INN
Inns are generally establishments or buildings where travelers can seek lodging, and usually, food and drink. Inns are typically located in the country or along a highway; before the advent of motorized transportation they also provided accommo ...
, trade names Oraspor and Cefthan-DS) is a cephalosporin 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 withdiazomethane
Diazomethane is the chemical compound CH2N2, discovered by German chemist Hans von Pechmann in 1894. It is the simplest diazo compound. In the pure form at room temperature, it is an extremely sensitive explosive yellow gas; thus, it is almost ...
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
In organic chemistry, ozonolysis is an organic reaction where the unsaturated bonds of alkenes (), alkynes (), or azo compounds () are cleaved with ozone (). Alkenes and alkynes form organic compounds in which the multiple carbon–carbon b ...
(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
Diazomethane is the chemical compound CH2N2, discovered by German chemist Hans von Pechmann in 1894. It is the simplest diazo compound. In the pure form at room temperature, it is an extremely sensitive explosive yellow gas; thus, it is almost ...
, 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
Trifluoroacetic acid (TFA) is an organofluorine compound with the chemical formula CF3CO2H. It is a structural analogue of acetic acid with all three of the acetyl group's hydrogen atoms replaced by fluorine atoms and is a colorless liquid with ...
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