HETEROCYCLYL DERIVATIVES OF OXY-IMINO-SUBSTITUTED CEPHALOSPORINS

The invention relates to heterocyclyl derivatives of oxyiminosubstituted cephalosporins of formula I wherein R represents an amino, aminocarbonyl or carboxy group; R1 represents a hydrogen atom or an amino-protecting group chosen from formyl, chloroacetyl, dichloroacetyl, tert-butoxycarbonyl, p-nitrobenzyloxycarbonyl and trityl; and R2 represents a hydrogen atom, a hydroxy-protecting group chosen from formyl, acetyl, chloroacetyl, dichloroacetyl, trifluoroacetyl, tetrahydrofuranyl, trityl, trimethylsilyl and dimethyl-tert-butyl-silyl or a branched or straight chain C1 - C4 alkyl group. The compounds display high antibacterial activity in animals and humans not only against Gram-positive and Gram-negative bacteria normally susceptible to cephalosporins such as staphylococci, streptococci, diplococci, Klebisiella, Escherichia coli, Proteus mirabilis, Salmonella, Shigella, Haemophilus and Neisseria, but also against the strong beta-lactamase producer Gram-negative micro-organisms, such as, for example, Klebsiella aerogenes 1082 E, Escherichia coli Tem, Enterobacter cloacae P 99, indolepositive Proteus and the like, as well as against Pseudomonas aeruginosa strains, which are normally resistant to most cephalosporins.