Synthesis, Characterization and Antimicrobial Evaluation of Novel Mannich Bases Containing Pyrazole-5-One Phosphonates

V. E. Rani*, L. K. Ravindranath
Department of Chemistry, S. K. University, Ananthapuramu, A.P, India

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© Rani and Ravindranath; Licensee Bentham Open.

open-access license: This is an open access article licensed under the terms of the Creative Commons Attribution-Non-Commercial 4.0 International Public License (CC BY-NC 4.0) (, which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.

* Address correspondence to this author at the Department of Chemistry, S. K. University, Ananthapuramu, A.P, India; E-mail:



Newly synthesised compounds of phosphonates were prepared by condensation of diethylphosphate with imine which undergoes a reaction of mannich bases with pyrazole containing schiffs base. The base was prepared by condensation of aldehyde with primary amine. These newly synthesised derivatives were characterised by spectral analysis.


Mannich bases are very important to synthesize wide variety of natural products and pharmaceuticals.


Thin Layer Chromatography was performed on aluminum sheet of silica gel 60F254, E-Merk, Germany using iodine as visualizing agent. IR Spectra were recorded as KBr pellets on Perkin-Elmer 1000 units, instruments. All 1H and 13C-NMR spectra were recorded on a Varian XL-300 spectrometer operating at 400MHz and 75 MHz. 31P-NMR spectra were recorded on a Varian XL-spectrometer operating at 161.89MHz. The compounds were dissolved in dimethylsulfoxide and Chemical shifts were referenced to Trimethylsilane (1H and 13C-NMR) and 85% phosphoric acid (31P-NMR).


Some of the novel synthetic compounds of Pyrazole Mannich base-Phosphonates showed great potential in field of medicinal chemistry and good biological activity.


It can be concluded that this class of compounds certainly holds great potential for the discovery of novel classes of antimicrobial agents.

Keywords: Antibacterial, Antifungal, Phosphonates, Pyrazole-5-one.