Synthesis and Biological Evaluation of Some Novel 1, 3, 5‐Trisubstituted Pyrazolines

Abstract

A new series of chalcones (3a-j) were synthesized by condensation of simple aldehydes with substituted acetophenones in presence of alkali. The resulted chalcones upon cyclization in presence of glacial acetic acid with isoniazid (INH) will yields the title compounds (4a-j). The newly synthesized compounds were assigned on the basis of IR,1H NMR, and Mass spectral data. All the final compounds were evaluated for theirin vitroantimicrobial activity.

4,5-Dihydro-1H-pyrazole: an indispensable scaffold

“…Revanasiddappa et al 63 synthesized and determined the pyrazoline derivatives for their in-vitro antimicrobial activity against different Gram-negative and Gram-positive bacterial strains as well as fungal strains. Although these compounds showed comparable antibacterial and antifungal activity, the activity (Table 12) is seen mainly due to the presence of electron withdrawing groups (Table 11) at R 1 on the C2 phenyl ring.…”

[5-(1,3-Diphenyl-1H-pyrazol-4-yl)-3-phenyl-4,5-dihydropyrazol-1-yl](pyridin-4-yl)methanone

“…Here, the DEPT-135 spectrum gives positive peaks at δ 53.62 due to CH of pyrazoline (i.e., C 5 ) and a negative (inverse) peak at 41.49 due to CH 2 of pyrazoline (C 4 ), respectively. The combination of 1 H-NMR, 13 C-NMR and DEPT-135 provides strong evidence in support of the structure assigned to this pyrazoline derivative. The MS (ESI) spectrum of compound 2 exhibits an M+1 peak at m/z = 470.…”

“…The cyclization of chalcone 1 into pyrazoline derivative 2 was further supported by 13 C-NMR of prototype compound in which C 4 and C 5 carbon resonate at δ 41.49 and 53.62, respectively, while the peaks due to carbonyl carbon (C=O) are observed at 167.82 ppm. These values are in close agreement with reported values of carbon C 4 and C 5 in pyrazolines [12].…”

Quantitative Structure Activity Relationship and Biological Activity Studies of 4-Methyl-2-(4-substituted phenyl)quinoline Derivatives

“…Generation of training set: The training set was constructed using a series of substituted quinoline based compounds as per literature method [30,31]. A total 30 molecules with different substitution on the quinoline scaffold were selected as training set with their known biological activities against bacteria and fungi.…”