System for the evaluation and synthesis of azo-pyrazole anticancer agents

Abstract

A system for the synthesis and evaluation of 3,5-dimethyl-4-(3'-methoxyphenylazo)-1-(4-cyanophenyl)pyrazole, comprising a module for the formation of a 3-[(substituted phenyl)azo]-2,4-pentanedione intermediate and a module for reflux cyclization with 4-cyanophenylhydrazine in ethanol with catalytic acetic acid and a module for TLC-controlled product control and recrystallization.

Description

Field of invention

[0001] The invention relates to medicinal chemistry systems that enable the synthesis, characterization and cytotoxicity evaluation of azo-substituted, 1,3,5-trisubstituted pyrazoles against human cancer cell lines, including standardized workflows for SH-SY5Y assays. Background of the invention

[0002] Pyrazole scaffolds are preferred scaffold structures in oncology due to their ability to activate kinase binding sites, tubulin interactions, and redox signaling pathways. Numerous trisubstituted pyrazoles exhibit micromolar to nanomolar cytotoxicity against various cell lines. Recent reviews highlight their synthetic accessibility via hydrazine-1,3-dicarbonyl condensations and multicomponent strategies, facilitating the rapid generation of compound libraries for SAR studies with aryl, cyano, and azo groups. SH-SY5Y neuroblastoma cells serve as a widely used in vitro model for cytotoxic substance screening and mechanistic apoptosis studies. Several pyrazole derivatives exhibit measurable, dose- and time-dependent growth inhibition. Azoaryl substituents modulate electronic properties and planarity, potentially enhancing DNA interactions and cellular uptake.This motivates the investigation of methoxyphenylazo substituents in combination with cyanophenyl groups on the pyrazole core. Summary of the invention

[0003] The invention relates to a system for the synthesis of 3,5-dimethyl-4-(3'-methoxyphenylazo)-1-(4-cyanophenyl)pyrazole. The synthesis proceeds by generating a 3-[(substituted phenyl)azo]-2,4-pentanedione intermediate, followed by cyclocondensation with 4-cyanophenylhydrazine under ethanol reflux with catalytic glacial acetic acid. The reaction is monitored by thin-layer chromatography (TLC), and the product is purified by recrystallization. The system includes a bioassay module in which the synthesized pyrazoles are tested for cytotoxicity against SH-SY5Y cells. The most active compound, with an IC50 value of approximately 19.18 µg / ml under standardized conditions, is identified. Detailed description

[0004] The synthesis pathway begins with diazotization and azo coupling to 3-[(3'-methoxyphenyl)azo]-2,4-pentanedione, which is then heated under reflux with 4-cyanophenylhydrazine (approx. 5 mmol) in ethanol with catalytic acetic acid to induce cyclization to the target product, 1,3,5-trisubstituted pyrazole. The reaction progress is monitored by thin-layer chromatography with suitable eluents to distinguish the starting diketone, hydrazine, and product. The endpoint is defined by the disappearance of the intermediate stains and the appearance of a single product band. The crude product is purified by solvent-optimized recrystallization to obtain analytically pure pyrazole suitable for spectral characterization and biological assays.

[0005] The structure was elucidated using FT-IR spectroscopy to confirm the azo (N=N) and cyano (C≡N) stretching vibrations, 1 H / 1313C NMR spectroscopy is used to assign 3,5-dimethyl signals, aromatic resonances, and hydrazone-derived positions, while mass spectrometry is used to confirm the molecular ion and diagnostic fragments according to established pyrazole characterization protocols. The platform enables the generation of closely related analogs by varying the arylazo donor or the arylhydrazine partner, thus allowing the systematic investigation of electronic effects on efficacy and selectivity.

[0006] For cytotoxicity testing, SH-SY5Y cells were cultured under standard conditions and exposed to graded pyrazole concentrations. Cell viability was quantified at various time points using colorimetric assays such as WST-1 or MTT to determine IC50. 50The system was designed to determine values ​​from concentration-response curves. The described compound achieved an IC50 value of approximately 19.18 µg / ml, thus demonstrating measurable antiproliferative activity within the range reported for pyrazole drugs in neuroblastoma models. The system can optionally integrate apoptosis parameters (annexin V / PI, caspase activation) and cell cycle analyses to contextualize the mechanisms of growth inhibition, as recommended in current studies on pyrazole oncology. The manufacturing scalability incorporates batch production with control of residual solvents and reagent traces; quality characteristics include melting point range, chromatographic purity, and spectral agreement with reference datasets. Data acquisition meets current standards for pyrazole anticancer candidates, enabling the comparison of different compound series and the iterative optimization of the structure-activity relationship.

Claims

[1] A system for the synthesis and evaluation of 3,5-dimethyl-4-(3'-methoxyphenylazo)-1-(4-cyanophenyl)pyrazole, comprising a module for the formation of a 3-[(substituted phenyl)azo]-2,4-pentanedione intermediate and a module for reflux cyclization with 4-cyanophenylhydrazine in ethanol with catalytic acetic acid and a module for TLC-controlled product control and recrystallization. [2] System according to claim 1, wherein the structure of the product is determined by FT-IR, 1 H / 13 The characterization of pyrazole is confirmed by C-NMR and mass spectrometry according to standard procedures. [3] System according to claim 1, further comprising an SH-SY5Y cytotoxicity module with graded dosing and viability assays for determining the IC50, wherein the lead compound has an IC50 of approximately 19.18 µg / ml. [4] System according to claim 1, wherein the variation of the substituents on the azoaryl donor and the N-1 aryl group allows for fine-tuning of the anticancer activity in accordance with current structure-activity relationships of pyrazoles.