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ABSTRACT:
The chemistry of heterocyclic compound is one of the most complex branch of organic chemistry, which is equally interesting for its theoretical Implications, for the delivery of its synthetic procedures and for physiological and industrial significance of heterocyclic compound. Pyrazole has been studied for over a century as an important class of heterocyclic compound and continue to attract considerable interest due to the broad range of biological activities they posses. Present review highlighted recent reports of various pharmacological activities of pyrazole and its derivatives. Several pyrazole derivatives in the literature showed important biological activities with their structures are covered in this review.
KEYWORDS- Pyrazole derivatives, heterocyclic aromatic compounds, pharmacological activities.
INTRODUCTION:
Pyrazole is an heterocyclic aromatic compound characterised by five membered ring structure mainly composed of carbon and nitrogen. Heterocyclic compound are cyclic organic substance which contain ring system at least one atom other than carbon. Pyrazole is the name given by Ludwig Knorr in 1883. Pyrazole proved to be an interesting class of heterocyclics was described for the first time by Buchnev, who obtained it by decarboxylation of pyrazole 3, 4, 5-tricarboxilic acid in1889.
Pyrazole 3,4,5-tricarboxyic acid pyrazole
Synthesis of pyrazole by decarboxylation of pyrazole 3, 4, 5-tricarboxylic acid.:
Pyrazole ring can be represented by different tautomeric structural form as,
Pyrazole Pyrazole Pyrazole
Tautomeric structures of the un-substituted pyrazole ring
3-n non-pyrazole and levo-3-(1-pyrazolyl) alanine are naturally occurring pyrazole derivatives.
Naturally occurring pyrazoles
Pyrazole is an five membered aromatic organic compound mainly composed of three carbon atom and two nitrogen atom in a adjacent positions and the unsubstituted parent compound.
Molecular Formula- C3H4N2
Molecular weight- 68.077
Molar refractivity- 18.77 ± 0.3 cm3
Molar volume - 60.9 ± 3.0 cm3
Parachor value- 161.9 ± 3.0 cm3
Index of refraction- 1.528 ± 0.02
Surface tension- 48.6 ± 3.0 dyne/cm
Polarizability- 7.44 ± 0.5 10-24 cm3
Monoisotopic mass- 68.037448
Monoisotopic mass- 68.037448 Da Pyrazole derivatives are the subject of many research studies due to their widespread potential biological activities. Literature survey showed that pyrazole and its derivatives posses various pharmacological activities such as antimicrobial, antifungal, anti-influenza, antiangiogenic, analgesic, anaesthetic, anticancer, antitubercular, antioxidants, anti-inflammatory, insecticidal, herbicidal and hypotensive.
1.1 Antibacterial Activity:
The antibacterial activity of metal complexes was found in the order of Au, Cd...