Macrocyclization can help improve pharmacological activity, metabolic stability, cell permeability and oral absorption to create better drug candidates. For example, enhancing the oral absorption o...
This invention provides cephalosporin compounds represented by the following general formula: ##STR1## wherein R.sup.1 and R.sup.2 are same or different hydrogen atom or a lower alkyl group of 1 to 5 carbon atoms; R.sup.3 is a lower alkyl group which may optionally be substituted with a halogen atome (or atoms), an alkenyl group, or a cycloalkylmethyl group of 3 to 6 carbon atoms; and A is hydrogen atom or residue of a nucleophilic compound and pharmacologically acceptable salts thereof. These compounds have broad-spectrum antibacterial activity against Gram-positive and -negative bacteria including Pseudomonas aeruginosa, as well as against a great variety of .beta.-lactamase-producing strains.
There is described a process for the preparation of 3-disubstituted cepham-4-carboxylic acid derivatives of formula I
1
wherein R″ is 4-methoxybenzyl, X is the residue of a thioether and Z is a residue of a nucleophilic compound and the conversion of these novel intermediates into the corresponding 3-cephem derivatives by oxidative cleavage of the mercaptan X-SH. By suitable deprotection, these 3-cephem derivatives afford cephalosporins such as ceftiofur, cefotaxime and ceftriaxone.