Vijesh, A.M.Isloor, A.M.Isloor, S.Shivananda, K.N.Shyma, P.C.Arulmoli, T.2026-02-052011Der Pharma Chemica, 2011, 3, 4, pp. 454-463https://idr.nitk.ac.in/handle/123456789/27182Invasive microbial infections are major problems around the world, especially in immuno compromised patients. The recent expansion of antimicrobial drug research has occurred because there is a critical need for new antimicrobial agents to treat these life threatening invasive infections. In the present study three series of new substituted pyrazolone derivatives (5a-f, 6a-f and 8a,b) were synthesized by the Knoevenagel condensation reaction of pyrazolones (3a,b) with various substituted carbaldehydes (4a-f, 7). These newly synthesized compounds were characterized by IR, NMR, mass spectra and also by C, H, N analyses. New compounds were screened for their antimicrobial studies against S. aureus, B. subtilis, E. coli and P. aeruginosa. The results revealed that compounds 5c and 6c having 2,5-dichlorothiophene substituent showed significant antibacterial activity against all tested microorganisms as compared to the standard drug Ceftriaxone.2 (2,4 dinitrophenyl) 4 [(6 methoxynaphthalen 2 yl)methylidene] 5 methyl 2,4 dihydro 3h pyrazol 3 one2 (2,4 dinitrophenyl) 4 [[3 (4 methoxyphenyl) 1h pyrazol 4 yl]methylidene] 5 methyl 2,4 dihydro 3h pyrazol 3 one2 (2,4 dinitrophenyl) 5 methyl 4 [[3 [4 (methylsulfanyl)phenyl] 1h pyrazol 4 yl]methylidene] 2,4 dihydro 3h pyrazol 3 one4 [(6 methoxynaphthalen 2 yl)methylidene] 5 methyl 2 phenyl 2,4 dihydro 3h pyrazol 3 one4 [[3 (2,4 dichlorophenyl) 1h pyrazol 4 yl]methylidene] 5 methyl 2 phenyl 2,4 dihydro 3h pyrazol 3 one4 [[3 (2,5 dichlorothiophen 3 yl) 1h pyrazol 4 yl]methylidene] 2 (2,4 dinitrophenyl) 5 methyl 2,4 dihydro 3h pyrazol 3 one4 [[3 (2,5 dichlorothiophen 3 yl) 1h pyrazol 4 yl]methylidene] 5 methyl 2 phenyl 2,4 dihydro 3h pyrazol 3 one4 [[3 (4 biphenyl) 1h pyrazol 4 yl]methylidene] 2 (2,4 dinitrophenyl) 5 methyl 2,4 dihydro 3h pyrazol 3 one4 [[3 (4 biphenyl) 1h pyrazol 4 yl]methylidene] 5 methyl 2 phenyl 2,4 dihydro 3h pyrazol 3 one4 [[3 (4 chlorophenyl) 1h pyrazol 4 yl]methylidene] 2 (2,4 dinitrophenyl) 5 methyl 2,4 dihydro 3h pyrazol 3 one4 [[3 (4 chlorophenyl) 1h pyrazol 4 yl]methylidene] 5 methyl 2 phenyl 2,4 dihydro 3h pyrazol 3 one4 [[3 (4 methoxyphenyl) 1h pyrazol 4 yl]methylidene] 5 methyl 2 phenyl 2,4 dihydro 3h pyrazol 3 one5 methyl 4 [[3 [4 (methylsulfanyl)phenyl] 1h pyrazol 4 yl]methylidene] 2 phenyl 2,4 dihydro 3h pyrazol 3 oneantibiotic agentceftriaxonepyrazolone derivativeunclassified drugantibacterial activityarticleBacillus subtiliscarbon nuclear magnetic resonancecontrolled studydrug determinationdrug effectdrug screeningdrug structuredrug synthesisEscherichia coliinfrared spectroscopymass spectrometryminimum inhibitory concentrationnitrogen nuclear magnetic resonancenonhumanproton nuclear magnetic resonancePseudomonas aeruginosaStaphylococcus aureus