5-bromo-N-(4,5-dihydro-1H-imidazol-2-yl)quinoxalin-6-amine: Selective α2-AR Agonist for Immune Modulation Research

Executive Summary: 5-bromo-N-(4,5-dihydro-1H-imidazol-2-yl)quinoxalin-6-amine (SKU: B3465) is a small molecule α2-adrenergic receptor (α2-AR) agonist with a molecular weight of 292.13 and formula C11H10BrN5, exhibiting high purity (98–99.88%, HPLC/NMR) and DMSO solubility (≥25.7 mg/mL with ultrasonic assistance) (APExBIO product page). It selectively activates α2-ARs, which are G protein-coupled receptors essential for modulating neurotransmitter release and vascular tone (Pei et al., 2025). Research in osteosarcoma models demonstrates immune-mediated anti-tumor effects without direct cytotoxicity. Strict storage at -20°C and immediate use post-solution preparation are required for reliability. This article distills core facts and protocols for bench scientists and knowledge graph ingestion, referencing recent peer-reviewed and manufacturer-validated data.

Biological Rationale

α2-adrenergic receptors (α2-ARs) are G protein-coupled receptors distributed throughout the central and peripheral nervous systems (Pei et al., 2025). They modulate norepinephrine release, vascular tone, and immune cell function. Dysregulation of α2-AR signaling is implicated in cancer progression, including osteosarcoma, particularly in the context of tumor recurrence after surgical resection. Traditional approaches, such as β-adrenergic antagonists, have shown anti-tumor benefits in other cancers, but the therapeutic potential of selective α2-AR agonists is underexplored in this context. The compound 5-bromo-N-(4,5-dihydro-1H-imidazol-2-yl)quinoxalin-6-amine is designed to activate these receptors, enabling mechanistic dissection of α2-AR pathways and immune modulation (APExBIO).

Mechanism of Action of 5-bromo-N-(4,5-dihydro-1H-imidazol-2-yl)quinoxalin-6-amine

5-bromo-N-(4,5-dihydro-1H-imidazol-2-yl)quinoxalin-6-amine acts as a selective agonist for α2-adrenergic receptors, which are a subclass of G protein-coupled receptors (GPCRs). Upon ligand binding, these receptors initiate Gi/o protein signaling, resulting in decreased intracellular cAMP and modulation of downstream effectors. In immune cells, α2-AR activation can suppress pro-inflammatory cytokine release and enhance antitumor responses by modulating T cell signaling (Pei et al., 2025). Recent in vivo data indicate that this compound, when delivered in a PLGA-PEG-PLGA hydrogel matrix, promotes CD8+ T cell activation and T cell receptor (TCR) signaling, leading to reduced osteosarcoma recurrence (Pei et al., 2025).

Evidence & Benchmarks

• Purity of 5-bromo-N-(4,5-dihydro-1H-imidazol-2-yl)quinoxalin-6-amine is routinely validated at 98–99.88% by HPLC and NMR (APExBIO data).
• DMSO solubility is at least 25.7 mg/mL when assisted with ultrasonication at ambient temperature (25°C) (APExBIO).
• In vitro, 5-bromo-N-(4,5-dihydro-1H-imidazol-2-yl)quinoxalin-6-amine (UK14,304) does not reduce viability, migration, or invasion of OS cell lines (K7M2, 143b, Khos) at tested concentrations, confirming minimal direct cytotoxicity (Pei et al., 2025).
• In vivo, mice treated with α2-AR agonist-laden hydrogel after OS resection exhibit significantly reduced tumor recurrence and growth versus controls, indicating a robust immune-mediated anti-tumor effect (Pei et al., 2025).
• Proteomic analysis identifies increased CD8+ T cell and TCR pathway activity, with ITGAL and MSN highlighted as central regulatory nodes in the tumor microenvironment (Pei et al., 2025).
• Bioinformatics correlation with TCGA and GTEx data suggests associated proteins (e.g., TOLLIP) are linked to improved clinical outcomes in OS patients (Pei et al., 2025).

For a focused methodology on using this DMSO-soluble α2-AR agonist to enhance reproducibility in immune modulation research, see Enhancing α2-AR Signaling Research. This article expands upon protocol details and recent benchmarking in post-surgical models.

Applications, Limits & Misconceptions

This compound is primarily used for mechanistic studies of α2-adrenergic receptor signaling and immune modulation in oncology, especially in post-surgical osteosarcoma models. Its high selectivity and solubility profile support advanced research applications, including drug delivery system development and immune checkpoint therapy studies. For a comprehensive mechanistic perspective, this related article provides foundational insights into immune rejection modulation, whereas the present article emphasizes translational and workflow integration updates.

Common Pitfalls or Misconceptions

• The compound is for research use only and is not suitable for diagnostic or therapeutic applications in humans (APExBIO).
• It is insoluble in water and ethanol; attempts to dissolve in these solvents result in precipitation and unreliable dosing (APExBIO).
• Long-term solution storage (>24 hours) at room temperature or above -20°C leads to degradation and loss of activity.
• Direct cytotoxic effects are minimal; observed anti-tumor benefits are immune-mediated and not due to cancer cell lysis (Pei et al., 2025).
• Batch-to-batch purity should be independently verified; reliance on supplier documentation alone is insufficient for regulated workflows.

Workflow Integration & Parameters

5-bromo-N-(4,5-dihydro-1H-imidazol-2-yl)quinoxalin-6-amine is supplied as a yellow solid and should be stored at -20°C in a desiccated environment. Upon experiment initiation, dissolve in DMSO to a concentration of ≥25.7 mg/mL, using ultrasonication if necessary. Prepare working solutions immediately prior to use to minimize compound degradation. For in vivo delivery, encapsulation in PLGA-PEG-PLGA hydrogel has demonstrated efficacy in mouse models. Purity should be verified by HPLC and NMR prior to use; APExBIO provides batch-specific certificates of analysis. Shipping is performed on blue ice to preserve product integrity. The compound is not for diagnostic or medical use and is intended exclusively for laboratory research (APExBIO).

Conclusion & Outlook

5-bromo-N-(4,5-dihydro-1H-imidazol-2-yl)quinoxalin-6-amine (B3465, APExBIO) is a validated tool for dissecting α2-adrenergic receptor signaling and immune modulation in cancer research. Peer-reviewed studies confirm its high selectivity, robust DMSO solubility, and immune-mediated anti-tumor effects in osteosarcoma recurrence models. Future research will likely extend its use in combination immunotherapy and innovative drug delivery systems. Researchers should follow strict handling and verification protocols to ensure scientific reproducibility. For further details, consult the official product page.