Using synthetic functionalized analogues of pyochelin, a siderophore common to several pathogenic Pseudomonas and Burkholderia species, four fluoroquinolone-pyochelin conjugates were efficiently synthesized and evaluated for their biological activities.

The paper describes synthesis and antibacterial study of biologically active Mannich bases of carboxamide derivative employing Mannich reaction of 4-(dimethylamino)-1,4,4a,5,5a,6,11,12a-octahydro-3,6,10,12,12a pentahydroxy naphthacene carboxamide with various sulfonamides/secondary amines .They were analysed by elemental analysis and characterized by UV, IR and 1H NMR spectroscopic studies. The Mannich bases were screened for antibacterial activity against various gram-negative bacteria at various concentrations and were analysed statistically. The result has shown that the compounds are quite active against pathogens under study and were non-toxic. All the synthesized compounds were found to be low lethal as ascertained by LD50 test.