Improved antibacterial activities of coumarin antibiotics bearing 5',5'-dialkylnoviose: biological activity of RU79115.

A new series of coumarin inhibitors of DNA gyrase B bearing a N-propargyloxycarbamate at C-3' of various 5',5'-dialkylnoviose, including RU79115, were synthesised and their antibacterial activities have been delineated. Introduction of dialkyl substituents at 5'5'-position of noviose leads to coumarin analogues with improved in vitro and in vivo antibacterial activity.

1,3-Disubstituted-2-carboxy quinolones: highly potent and selective endothelin A receptor antagonists.

The design, synthesis, and in vitro biological activity of a series of 2-carboxy quinolone antagonists selective for the endothelin A receptor are presented. Introduction of a second acid group in position 3 of the quinolone ring increases dramatically the selectivity for ET(A).