Pyrazole and Its Derivatives: An Excellent N-Hetrocycle with Wide Range of Biological Applications (A Review)

Abstract

The pyrazole derivatives have been recognized as a unique heterocyclic molecule exerting broad range of biological activities such as analgesic, anti-viral, anti-histaminic, anti-microbial, anti-tumor, insecticides fungicides, anti-depressant, antipyretic, anti-inflammatory, angiotensin converting enzyme (ACE) inhibitory and estrogen receptor (ER) ligand activity etc. Pyrazoles also find applications in agrochemical and pharmaceutical industry. Pyrazoles have different chemical properties which may be attributed due to the effect of particular N-atoms present in pyrazole molecule. N-Atom present at position-2 having non Huckel lone pair is more reactive towards electrophiles while N-atom present at position-1 is unreactive. However, in the presence of strong base, the proton from N-atom at position-1 is abstracted thereby providing pyrazole anion after deprotonation, which in turn increases reactivity towards the electrophiles. There are wide range of drugs available in the market possessing pyrazole nuclei. The present manuscript is aimed to describe major developments achieved till date towards the synthesis and biological applications of pyrazole/pyrazole derivatives and is likely to be beneficial to the researchers working in the area.