Pyrazole and its derivatives are considered a pharmacologically important active scaffold that possesses almost all types of pharmacological activities. The presence of this nucleus in pharmacological agents of diverse therapeutic categories such as celecoxib, a potent anti-inflammatory, the antipsychotic CDPPB, the anti-obesity drug rimonabant, difenamizole, an analgesic, betazole, a H2-receptor agonist and the antidepressant agent fezolamide have proved the pharmacological potential of the pyrazole moiety. Owing to this diversity in the biological field, this nucleus has attracted the attention of many researchers to study its skeleton chemically and biologically. This review highlights the different synthesis methods and the pharmacological properties of pyrazole derivatives. Studies on the synthesis and biological activity of pyrazole derivatives developed by many scientists around the globe are reported.

Synthesis and Pharmacological Activities of Pyrazole Derivatives: A Review

Coumarin heterocyclic derivatives: chemical synthesis and biological activity

The therapeutic voyage of pyrazole and its analogs: A review.

Recently reported biological activities of pyrazole compounds.

Recent developments of coumarin-containing derivatives and their anti-tubercular activity

Synthesis of novel coumarin appended bis(formylpyrazole) derivatives: Studies on their antimicrobial and antioxidant activities.

Synthesis and biological evaluation of novel formyl-pyrazoles bearing coumarin moiety as potent antimicrobial and antioxidant agents.

Objective: The aim of the present work was to synthesize fused pyrazoles and examine them for their in vitro antimicrobial activity. Methods: The formyl pyrazoles were synthesized by Vilsmeier–Haack reaction from o- hydroxy acetophenone hydrazones. The pyrazoles on oxidative cyclisation in the presence of ethanol and catalytic amount of H 2 SO 4 yielded pyrano [4,3- c ] pyrazoles. The structures of the synthesized derivatives were confirmed by Mass, 1 H NMR and elemental analysis. The synthesized new pyranopyrazoles were screened for their antimicrobial activity by broth dilution technique. Results: The results of the antimicrobial assay revealed that the compound 4b having chloro substitution showed good activity against different microorganisms tested. Conclusion: It is noteworthy that the compounds synthesized by a simple and accessible procedure leads to a molecules of promising antimicrobial activity.

Synthesis and antimicrobial activity of novel fused pyrazoles

A convenient protocol for the synthesis of coumarin appended 1,3-benzoxazine derivatives (4a – 4g) is described. Cyclisation of hydrazones (3a – 3g) using triphosgene in dichloromethane gave the corresponding 1,3-oxazines in a relatively good yield. The proposed structures of newly synthesized compounds were confirmed by spectral methods and elemental analysis. Oxazine derivatives 4a – 4g were evaluated for their in vitro antimicrobial activity against various bacteria and fungi. Compounds 4b and 4d inhibited growth of test microbes thus proving significant antimicrobial activity. In addition, in vitro antioxidant activity of the synthesized compounds was evaluated and compared to that of standards, showing DPPH, NO, and OH radical scavenging properties. Compounds 4b and 4f exhibited higher antioxidant activity than a standard drug.

Renuka Nagamallu

Papers

Synthesis of novel coumarin appended bis(formylpyrazole) derivatives: Studies on their antimicrobial and antioxidant activities.

Synthesis and biological evaluation of novel formyl-pyrazoles bearing coumarin moiety as potent antimicrobial and antioxidant agents.

Synthesis and antimicrobial activity of novel fused pyrazoles

Synthesis of Coumarin Appended 1,3-Oxazines as Potent Antimicrobial and Antioxidant Agents