| 摘要 |
<p>The subject matter of the invention is a process for producing 3-cephem-4-carboxylic acid derivatives substituted in 3-position of formula (I) <CHEM> wherein R2 is thienyl, diazolyl, thiazolyl, tetrazolyl, thiadiazolyl, thiatriazolyl, oxazolyl, oxadiazolyl, pyridyl, pyrimidinyl, benzothiazolyl, benzimidazolyl, benzoxazolyl or any of their substituted derivatives in any of the possible positions of the mentioned heterocyclic residues available for substitution, which is characterized in that a 7-amino-cephalosporanic acid derivative of formula (II) <CHEM> wherein R1 means -OOCCH2 is reacted with a thiol R2SH. The compounds I may be effectively purified by adsorption on a strongly basic anion exchange resin. The compounds I which are obtained by the process of the invention are valuable intermediates in the synthesis of therapeutically useful cephalosporins.</p> |
