Synthesis and antimicrobial properties of substituted 3-aminoxypropionyl and 3-aminoxy-(E)-2-methoxyiminopropionyl monobactams.

The substituted 3-aminoxyproprionyl (VII) and 3-aminoxy-(E)-2-methoxyiminopropionyl monobactams (VIII) which possess the monocyclic beta-lactam nucleus of aztreonam (IX) were synthesized by reaction of triethylammonium (3S, 4S)-3-amino-4-methyl-2-oxo-1-azetidinsulfonate with the aminoxy acids X and XI, respectively. Compounds VII and VIII were assayed in vitro for their antimicrobial properties against Gram-positive and Gram-negative bacteria, whether producers of beta-lactamases or otherwise. Both types of compounds (VII and VIII) exhibited a poor antibacterial activity towards Gram-positive bacteria, comparable to that of aztreonam. On the contrary VII and VIII proved to be practically inactive against Gram-negative microorganisms, towards which aztreonam exhibits a high degree of activity.