Abstract

Subba Narayana Kanchana*, Venkataramudu Burra, L. K. Ravindra Nath

DOI : http://dx.doi.org/10.13005/ojc/300354

In the present study, synthesis, characterization, antimicrobial activity on some novel pyrazolone derivatives has been taken up. The primary amines were diazotized with sodium nitrite and HCl mixture at 0-5 ⁰C which were further coupled with ethyl acetoacetic ester to afford phenyl diazonium acetoacetic esters (II). Condensation of 4-substituted aryl hydrazono acetoacetic ester, 4-hydrazinylbenzenamine in the presence of catalytic amount of DMF under microwave irradiation afforded (4Z)-4-(2-substituted aryl hydrazono)-1-(4-aminophenyl)-3-methyl-1H-pyrazol-5(4H)-one (III). Subjecting (III) to anhydrous K₂CO₃ in DMF for 8 hours afforded 2-{4-[(4Z)-4-(2-substituted aryl hydrazono)-4, 5-dihydro-3-methyl-5-oxopyrazol-1-yl] phenyl amino} acetate( IV) which was further reacted with hydrazine hydrate to afford 2-{4-[(4Z)-4-(2-substituted aryl hydrazono)-4, 5-dihydro-3-methyl-5-oxopyrazol-1-yl] phenylamino} acetohydrazide (V). Reaction of (V) and Isatin (VI b) in DMF afforded (4Z)-2-(4-((15Z)-4-(2-phenylhydrazono)-4,5-dihydro-3-methyl-5 oxopyrazol-1-yl)phenylamino)-N'-(2-oxoindolin-3-ylidene)acetohydrazide (VII). Compound  (VII) was subsequently subjected to Mannich reaction with cyclic secondary amines (piperidine/morpholine/N-methyl piperidine) in the presence of formaldehyde in DMF to afford (4Z)-2-(4-((15Z)-4-(2-substituted aryl hydrazono)-4,5-dihydro-3-methyl-5-oxopyrazol-1-yl)phenylamino)-N'-(2-oxo-1-((piperidin-1-yl)methyl)indolin-3-ylidene)acetohydrazide (VIII) which was characterized by I.R, ¹HNMR and Mass data. The anti-bacterial activity of synthesized compounds was studied by the disc diffusion method against pathogenic bacteria and fungi.

Mannich Reaction; Mannich Base; Anti-microbial Activity

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