Bioactive Fused Pyrazoles Inspired by the Adaptability of 5-Aminopyrazole Derivatives: Recent Review.

Heterocyclic compounds, especially those containing the pyrazole moiety, are highly significant in organic chemistry and possess remarkable and diverse biological properties. The 5-aminopyrazole derivatives are key starting materials for the synthesis of numerous bioactive compounds such as pyrazolopyridine, pyrazolopyrimidine, pyrazoloquinazoline, and pyrazolotriazine derivatives. Many compounds inspired by the 5-aminopyrazole derivatives possess a wide spectrum of biological activities and medicinal applications such as antioxidants, anticancer agents, enzyme inhibitors, antimicrobials, and anti-tuberculosis activities.

Evaluation of Pyrazolyl-Indolizine Derivatives as Antimicrobial Agents: Synthesis, In vitro, In silico ADMET and Molecular Docking Studies.

Herein, we report analogues of s-indacene by the synthesis of novel indolizine derivatives. Using chloroform as an appropriate solvent, sixteen derivatives of pyrazolyl-indolizine (4--19) were prepared by the reaction of 3-(dimethylamino)-1-(1H-pyrrol-2-yl)prop-2-en-1-one (1) with hydrazonoyl chloride derivatives (2) in the presence of triethylamine in good to excellent yields. We used NMR spectra, IR, mass spectrometry, as well as elemental analyses to prove the chemical structures and the purity of the synthesized compounds 4-19.

Synthesis, Characterization, and Cytotoxicity of Some New 5-Aminopyrazole and Pyrazolo[1,5-a]pyrimidine Derivatives.

5-Amino-N-aryl-3-[(4-methoxyphenyl)amino]-1H-pyrazole-4-carboxamides 4a-c were synthesized by the reaction of N-(aryl)-2-cyano-3-[(4-methoxyphenyl)amino]-3-(methylthio)acrylamides 3a-c with hydrazine hydrate in ethanol. The reaction of 5-amino-N-aryl-1H-pyrazoles 4a-c with acetylacetone 5 or 2-(4-methoxybenzylidene)malononitrile 8 yielded the pyrazolo[1,5-a]pyrimidine derivatives 7a-c and 10a-c, respectively. The structures of the synthesized compounds were established based on elemental analysis and spectral data (IR, MS, (1)H-NMR, and (13)C-NMR).

Synthesis, Structural Elucidation, and In Vitro Antitumor Activities of Some Pyrazolopyrimidines and Schiff Bases Derived from 5-Amino-3-(arylamino)-1H-pyrazole-4-carboxamides.

The reaction of 5-amino-3-(arylamino)-1H-pyrazole-4-carboxamides 1a,b with acetylacetone 2 and arylidenemalononitriles 5a-c yielded the pyrazolo[1,5-a]-pyrimidine derivatives 4a,b and 7a-f respectively. On the other hand, Schiff bases 9a,b and 12a-j were obtained upon treatment of carboxamides 1a,b with isatin 8 and some selected aldehydes 11a-e. The newly synthesized compounds were characterized by analytical and spectroscopic data.