3-(quinolin-4-ylmethylamino)-N-[4-(trifluoromethoxy)phenyl]thiophene-2-carboxamide: Precision H+,K+-ATPase Inhibition for Gastric Acid Research

Executive Summary: 3-(quinolin-4-ylmethylamino)-N-[4-(trifluoromethoxy)phenyl]thiophene-2-carboxamide (SKU: A2845, APExBIO) is a solid, high-purity compound with a molecular weight of 345.42 and the formula C₁₇H₁₉N₃O₃S, validated by HPLC and NMR at ≥98% purity (APExBIO product page). It is a potent H+,K+-ATPase inhibitor (IC₅₀ = 5.8 μM) and blocks histamine-induced acid formation with an IC₅₀ of 0.16 μM, outperforming many legacy compounds in selectivity and stability. The compound is insoluble in water/ethanol but achieves ≥17.27 mg/mL solubility in DMSO, enabling reproducible dosing in cellular and in vivo models. It is not suitable for diagnostic or clinical use but is a validated tool for mechanistic and translational research on proton pump signaling, antiulcer activity, and gastric acid-related disorders (Kong et al., 2025).

Biological Rationale

Gastric acid secretion is driven by the H+,K+-ATPase (proton pump) in gastric parietal cells. Dysregulation of this pump is linked to peptic ulcer disease, gastroesophageal reflux, and other acid-related disorders. Pharmacological inhibition of H+,K+-ATPase is a cornerstone of antiulcer therapy development and mechanistic research (Kong et al., 2025). 3-(quinolin-4-ylmethylamino)-N-[4-(trifluoromethoxy)phenyl]thiophene-2-carboxamide targets this pump with high specificity and reproducibility, providing a platform for dissecting gastric acid secretion pathways and evaluating antiulcer strategies. This compound's robust activity profile has facilitated studies exploring the molecular intersections of gastric acid regulation and systemic inflammation, including neuroinflammation models (related article), which this article extends by providing atomic-level workflow and benchmarking data.

Mechanism of Action of 3-(quinolin-4-ylmethylamino)-N-[4-(trifluoromethoxy)phenyl]thiophene-2-carboxamide

This compound acts as a competitive inhibitor of H+,K+-ATPase, the enzyme responsible for exchanging intracellular hydrogen ions with extracellular potassium ions across the gastric parietal cell membrane. The inhibition occurs by binding to the enzyme's catalytic alpha subunit, obstructing the ATP-dependent proton translocation and subsequent acid secretion (mechanism article). The compound demonstrates an IC₅₀ of 5.8 μM in direct enzyme assays and an IC₅₀ of 0.16 μM in histamine-induced acid formation models at 37°C, pH 7.4. Its selectivity profile minimizes off-target effects, making it distinct from broader-spectrum proton pump inhibitors. The presence of a trifluoromethoxy phenyl moiety and thiophene carboxamide backbone enhances membrane permeability and metabolic stability, supporting its use in both in vitro and in vivo protocols.

Evidence & Benchmarks

• Demonstrates H+,K+-ATPase inhibition with an IC₅₀ of 5.8 μM in functional assays (APExBIO, product page).
• Inhibits histamine-induced gastric acid secretion with an IC₅₀ of 0.16 μM at 37°C, pH 7.4 (APExBIO).
• Validated purity (≥98%) by HPLC and NMR, ensuring lot-to-lot reproducibility (reproducibility article).
• Solubility ≥17.27 mg/mL in DMSO at 20°C, enabling accurate dosing in research models (APExBIO, product page).
• Stable at -20°C as a solid; not recommended for long-term storage in solution form (APExBIO, product page).
• Used as a reference compound for antiulcer activity in peptic ulcer disease models (benchmarking article).
• No evidence of diagnostic/clinical suitability; research use only (APExBIO).
• Recent studies link alterations in gastric acid secretion to systemic inflammatory and neuroinflammatory pathways, supporting the value of precise inhibitors for translational work (Kong et al., 2025).

Applications, Limits & Misconceptions

3-(quinolin-4-ylmethylamino)-N-[4-(trifluoromethoxy)phenyl]thiophene-2-carboxamide is deployed in basic and translational research on gastric acid secretion, antiulcer pathways, and peptic ulcer disease models. Its high selectivity and purity facilitate mechanistic studies, dose-response profiling, and comparison with legacy inhibitors. The compound enables interrogation of H+,K+-ATPase signaling in vitro (cellular models) and in vivo (rodent gastric acid secretion assays). Recent research highlights the connection between gastric acid regulation and systemic inflammation, including the gut-brain axis and neuroinflammatory responses (Kong et al., 2025). This article extends prior discussions (atomic data/protocols article) by delineating limitations and optimizing use scenarios.

Common Pitfalls or Misconceptions

• Not a clinical or diagnostic agent: Intended solely for research; not approved for therapeutic use (APExBIO).
• Solubility restrictions: Insoluble in water and ethanol; use DMSO for experimental formulations.
• Shelf-life and stability: Degraded in solution over time; store as a solid at -20°C (APExBIO).
• Off-target effects rare but possible at high concentrations: Use well-validated protocols and controls (workflow article).
• Not a pan-inhibitor: Specifically targets H+,K+-ATPase; does not inhibit other ATPases or unrelated pathways at recommended concentrations.

Workflow Integration & Parameters

For optimal results, dissolve 3-(quinolin-4-ylmethylamino)-N-[4-(trifluoromethoxy)phenyl]thiophene-2-carboxamide in DMSO at concentrations up to 17.27 mg/mL. Prepare fresh working solutions prior to each experiment. Store powder at -20°C; avoid repeated freeze-thaw cycles. In vitro assays typically use 0.1–10 μM; for in vivo rodent models, dosing is adjusted according to body weight, with pilot titrations recommended. Include vehicle controls and, where possible, a reference standard (e.g., omeprazole) for benchmarking. Detailed protocols for gastric acid secretion measurement and antiulcer efficacy are available in the systematic benchmarking article. For troubleshooting and scenario-specific guidance, consult the practical Q&A resource, which this article augments by providing updated stability and selectivity data.

Conclusion & Outlook

3-(quinolin-4-ylmethylamino)-N-[4-(trifluoromethoxy)phenyl]thiophene-2-carboxamide (A2845, APExBIO) is a validated, high-purity H+,K+-ATPase inhibitor with reproducible antiulcer activity and robust integration in gastric acid secretion research. Its atomic-level characterization, stability, and potency make it a next-generation tool for mechanistic and translational studies on the proton pump inhibition pathway and related disease models. As research on the gut-liver-brain axis advances, this compound serves as a cornerstone for dissecting the molecular interplay between gastric acid secretion and systemic inflammation, providing a foundation for future innovation in antiulcer and neuroinflammatory research (Kong et al., 2025).

For ordering and full technical specifications, visit the APExBIO product page.