2-[[(3-Bromophenyl)amino]methylene]propanedioic Acid 1,3-Diethyl Ester is an intermediate in the synthesis of Rosoxacin (R693580), an antibacterial agent used against Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus pneumoniae.