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Nortadalafil (Demethyltadalafil) Research Standard
Nortadalafil, also referred to as Demethyltadalafil, is a synthetic structural analog of the phosphodiesterase type 5 (PDE5) inhibitor tadalafil. Structurally distinguished by the absence of the N-methyl group on the piperazinedione ring, this compound serves as a critical analytical reference standard. It is extensively utilized in forensic and pharmaceutical laboratories for impurity profiling, as it often appears as a process-related byproduct or an undeclared adulterant in complex matrices. Its high-fidelity chemical profile makes it a vital tool for validating analytical methods and conducting structure-activity relationship (SAR) investigations within the PDE5 inhibitor class.
Technical Specifications
| Property | Specification |
|---|---|
| Product Name | Nortadalafil (Demethyltadalafil) |
| CAS Number | 171596-36-4 |
| Chemical Formula | C₂₁H₁₇N₃O₄ |
| Molecular Weight | 375.38 g/mol |
| Chemical Class | PDE5 Inhibitor Analog |
| Physical Appearance | White to off-white solid |
| Assay Purity | Refer to the batch-specific Certificate of Analysis (COA) supplied for the lot received |
| Solution Base | PEG400, DMSO |
Mechanism of Action & Research Context
Nortadalafil functions as a competitive inhibitor of the PDE5 enzyme, sharing the core pharmacophore of the parent compound tadalafil while possessing distinct binding kinetics due to the structural modification.
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Enzyme Interaction: The presence of the amide bond and the piperazinedione ring allows the molecule to occupy the catalytic site of the PDE5 enzyme. Its structural configuration—featuring multiple hydrogen bond donors and acceptors—enables it to compete effectively with cyclic guanosine monophosphate (cGMP) in binding pockets.
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Impurity Profiling: Because nortadalafil is a known process-related impurity in the synthesis of tadalafil, it is indispensable for pharmaceutical compliance testing, ensuring that generic manufacturing processes remain within regulatory thresholds for purity.
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Structural Comparison: The benzodioxole ring contributes to its three-dimensional conformation, and researchers use this compound to compare how the absence of the N-methyl group alters steric hindrance and binding affinity relative to tadalafil.
Research Applications
Nortadalafil is a specialized reagent essential for analytical validation and toxicological screening.
Primary fields of in vitro laboratory investigation include:
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Binding Studies: Utilizing isolated PDE5 enzyme preparations and competitive displacement assays to quantify the binding affinity of nortadalafil versus radiolabeled ligands.
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Impurity Profiling: Mapping and identifying synthesis by-products in tadalafil drug substances to satisfy pharmacopoeial monograph compliance.
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Forensic Screening: Acting as a certified reference standard for LC-MS/MS methods to identify undeclared PDE5 inhibitors in complex dietary supplement samples.
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SAR Analysis: Serving as a baseline tool to study how subtle demethylation influences chromatographic retention times and mass spectral fragmentation patterns.
Storage & Handling Guidelines
Store at controlled room temperature. Keep tightly closed. Liquid formats: do not refrigerate or freeze. Cold storage may cause the solution to cloud or precipitate. If this occurs, return to room temperature and mix until clear.
Storage guidance is a house recommendation. Analytical documentation is per-lot release testing.
References
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BenchChem. (2026) Nortadalafil (CAS 171596-36-4) | PDE5 Inhibitor Impurity Ref. Standard.
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Synthink Research Chemicals. (2026) Tadalafil EP Impurities & USP Related Compounds.
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Creative Enzymes. (2026) Nortadalafil Product Overview.
Related Research Compounds
Research Use Disclaimer
Research Use Only Disclaimer: This product is developed and distributed strictly as a Research Use Only (RUO) laboratory reference chemical intended exclusively for non-clinical analytical and scientific investigation. It is not an FDA-approved drug, medication, dietary supplement, or food ingredient, and is strictly prohibited for human or animal consumption. Kimera Chems supplies this research material solely to qualified institutions and professional investigators for authorized laboratory research.
