Background: Recently, pyrazole derivatives have shown significant antiinflammatory activity. Non-steroidal anti-inflammatory drugs have some side effects, mainly gastric irritation and gastric ulceration during the treatment of inflammation. So the current study deals with the synthesis and pharmacological evaluation of a series of novel pyrazole derivatives as anti-inflammatory agents.
Methods: A series of novel ethyl 5-(substituted)-1H-pyrazole-3-carboxylate (2a-j) were synthesized and evaluated for anti-inflammatory activity using carrageenan-induced inflammation in rat paw edema model. In the first step, diethyl oxalate react with acetophenone derivatives in presense of sodium ethoxide to form substituted ethyl-2,4-dioxo-4- phenyl butanoate derivatives as intermediate (1a-j). Further the suspension was prepared from dioxo-esters with hydrazine hydrate in glacial acetic acid yielded novel ethyl 5- (substituted)-1H-pyrazole-3-carboxylate (2a-j) derivatives. The structure of the final analogues (2a-j) has been confirmed on the basis of elemental analysis, IR, 1 H NMR and mass spectra.
Results: All the values of elemental analysis, FTIR, 1H NMR, and mass spectra were found to be prominent. The anti-inflammatory activity test revealed that Ethyl 5-(3,4- dimethoxyphenyl)-1H-pyrazole-3-carboxylate (2f) and ethyl 5-(2,3-dimethoxyphenyl)-1Hpyrazole- 3-carboxylate (2e) exhibited significant anti-inflammatory activity as compared to control group.
Conclusion: The results of the current study indicate that the substitution at pyrazole scaffold could improve anti-inflammatory activity.