Pyrazoline

Pyrazolines, the eminent five-membered nitrogen-containing heterocyclic compounds, have received significant interest in the fields of therapeutic and agricultural chemistry because of their broad spectrum of biological activities. The Pyrazoline ring is relatively stable and has inspired chemists to carry out various research activities. Pyrazolines, a class of electron-rich nitrogen heterocyclic compounds, possess a broad range of pharmacological functions such as anticancer, antitubercular, antimalarial, antibacterial, antifungal, anti-inflammatory, analgesic, anticonvulsant, and antioxidant activities. This review provides an outline on the recent grade of pyrazoline derivatives in terms of synthesis and various applications to realize their full potential as drugs.

Different phenacyl bromides were reacted with 2-amino pyridine to give 2-aryl imidazo[1,2-a] pyridines, which on subsequent reaction with Vilsmeier-Haack reagent gave 2-aryl imidazo[1,2-a] pyridine carbaldehydes (4a-4b). Claisen-Schmidt condensation of 4a and 4b with different substituted acetophenones afforded chalcones (5a-5f). The reaction of chalcones with phenyl hydrazine gave six new derivatives of pyrazolyl imidazo[1,2-a]pyridines (6a-6f ) in good yields. The synthesized compounds were characterised on the basis of physical and spectral data. The compounds were evaluated for anti-inflammatory and anti-bacterial activities. The compounds 6a, 6b, and 6c exhibited potent anti-inflammatory activity and results are comparable with standard drug, ibuprofen. None of the compounds showed any significant antimicrobial activity even at a concentration of 1000 µg/ml against Gram +ve and Gram –ve organisms.

Some novel series of pyrazoline derivatives were synthesized from Chalcones. Chalcones were prepared by treatment of Paracetamol with different aldehyde by Claisen-Schimidt Condensation. Various Pyrazoline derivatives were prepared by reflux reaction of Chalcone with Phenyl Hydrazine/Hydrazine Hydrate in ethanolic solution. The structures of the newly synthesized Pyrazoline derivatives have been established on the basis of their spectral data. Structures of compounds were confirmed by IR, H1 NMR. The synthesized selected compounds were screened for their antimicrobial activity.