1-[3/-(SUBSTITUTED PHENYL) -5/- (AMINO PYRIMIDINE)]- 3- (4/-NITRO PHENYL) 5-(SUBSTITUTED PHENYL)- 2-PYRAZOLINES: SYNTHESIS, CHRACTERISATION AND ANTIMICROBIAL SCREENING

In the present study eight novel 2-pyrazoline – amino pyrimidine hybrids have been synthesized in order to search new chemical entities with increased pharmacological properties. The targeted analogues were synthesized in four steps; Claisen-schmidt condensation of 4-nitro acetophenone with different benzaldehydes in basic medium to yield precursor chalcone which was cyclised using hydrazine hydrates and acetic acid to form 1-acetyl-2-pyrazoline. These were condensed with substituted benzaldehydes to give corresponding pyrazolyl chalcones, which were cyclised using guanidine carbonate to obtain 2-pyrazoline-amino pyrimidine hybrids. All the synthesized compounds were characterized by elemental and spectral (¹H and ¹³C NMR, FTIR and Mass) analysis. All the compounds have been screened for their anti-bacterial activity against gram positive bacteria (Bacillus substilis, Streptococcus aureus), gram negative bacteria (Pseudomonas aeruginosa, Escherichia coli) and antifungal activity against Aspergillus niger comparable to reference standard ciprofloxacin and fluconazole by agar-well diffusion method.  All compounds 4(a-h) exhibited moderate to high activity and showed more pronounced antibacterial activity than antifungal activity. 4h showed dual effect antibacterial as well as antifungal agent.