Abstract: Catacholate beta-lactam conjugates, methods for producing these compounds, and compositions containing these compounds useful as siderophores or for treatment of bacterial infections are provided.

Abstract: The maduraphthalazine derivatives of the formula (4) are able to inhibit the effect of the cytokines interleukin-2, interleukin-4 and interleukin-5 and are suitable for the production of pharmaceuticals.

Abstract: Catechol derivatives of general formula (I) in which R1 denotes O-acyl and R2 represents amino acid residues in the 3- and/or 4-position function as siderophores and/or as biological chelating agents for iron in gram-negative bacteria. Conjugates with antibiotics improve penetration into bacterial cells, thereby increasing antibacterial efficacy of the cells.

Abstract: Polycyclic phthalazines, in particular 2-substituted maduraphthalazines (10,12,15,16-tetrahydroxy-8-methoxy-11-methyl-1,9,14-trioxo-1,2,6,7,9,14-h exahydronaphthaceno-1,2-g-phthalazines), of formula I and their use against gram-positive bacterial strains, particularly against multi-resistant staphylococci (MRSA) and against glycopeptide-resistant, for example vancomycin-resistant, enterococci. The polycyclic phthalazines are thus suitable for preparing anti-bacterially effective pharmaceutical compositions. In formula I, R.sup.1 is carboxyalkyl or carboxyaryl, and R.sup.2 and R.sup.3 represent H or acyl (for example CO-alkyl or COO-alkyl), with R.sup.1 being different from optionally substituted carboxyphenyl when R.sup.3 represents C.sub.1-8 alkanoyl. The invention also relates to salts, amides and esters of compounds of formula I.

Abstract: This invention relates to new benzoxazinedione derivatives corresponding to the formula I: ##STR1## wherein R.sup.1 =H or carboxyalkyl, R.sup.2 =H, alkyl or phenyl, and R.sup.3 represents different acid groups derived from amino acids, dipeptides and hydrazones or conjugates thereof with active ingredients, e.g. antibiotics. The compounds may be present as free acids, in the form of their salts or as readily cleavable esters. The compounds according to the invention constitute heterocyclically protected catechol derivatives and are effective as siderophores against gram-negative bacterial strains, particularly against Pseudomonads and strains of E. coli and Salmonella. In the form of their conjugates with active ingredients, e.g. antibiotics (as "siderophore-antibiotic conjugates"), they can transport the latter into bacterial cells and can improve or extend the antibacterial effect thereof, sometimes even in relation to bacterial strains which are resistant to other .beta.-lactams.