What is Aminotadalafil?

Aminotadalafil (known chemically as Amino Tadalafil or (6R,12aR)-2-amino-6-(1,3-benzodioxol-5-yl)-2,3,6,7,12,12a-hexahydropyrazino[1′,2′:1,6]pyrido[3,4-b]indole-1,4-dione) is a synthetic β-carboline derivative featuring an N-amino modification on its diketopiperazine core. Classified as a selective phosphodiesterase type 5 (PDE5) inhibitor reference compound, Aminotadalafil targets catalytic zinc-binding domains within PDE enzymes to stabilize intracellular cyclic guanosine monophosphate (cGMP) pools.

Formulated and analytical batch-verified for Modern Aminos, Aminotadalafil is supplied as a high-purity solid reference material for laboratory analytical screening, HPLC method development, and competitive enzyme binding assays. Researchers investigating PDE isoform selectivity, mass spectrometry fragmentation patterns, and vascular smooth muscle relaxation pathways utilize Aminotadalafil alongside related structural analogs offered on the site, such as Nortadalafil.

Chemical and Molecular Data

Compound Name	Aminotadalafil
Format & Packaging	Analytical-Grade Reference Powder / Sealed Glass Reagent Vial
Synonyms / Alt Names	Amino Tadalafil, Tildenafil Impurity 18, N-Desmethyl N-Amino Tadalafil
CAS Number	385769-84-6
Chemical Formula	C₂₁H₁₈N₄O₄
Molecular Weight	390.40 g/mol
IUPAC Name	(6R,12aR)-2-amino-6-(1,3-benzodioxol-5-yl)-2,3,6,7,12,12a-hexahydropyrazino[1′,2′:1,6]pyrido[3,4-b]indole-1,4-dione
InChIKey	VUKJGAVIWMPOOJ-FOIQADDNSA-N
SMILES Code	`NN1CC(=O)N2[C@H](Cc3c([nH]c4ccccc34)[C@H]2c2ccc3OCOc3c2)C1=O`

What are the Mechanisms of Action?

The biochemical pathways and cellular targets of Aminotadalafil in laboratory research include:

Selective Phosphodiesterase-5 (PDE5) Catalytic Inhibition: Research demonstrates that Aminotadalafil occupies the hydrophobic catalytic pocket of the PDE5 enzyme. By competing with native cGMP for active site binding, it blocks the hydrolytic cleavage of cGMP into inactive 5′-GMP, maintaining elevated intracellular second-messenger concentrations.
Nitric Oxide (NO) / cGMP Signal Amplification: In vascular smooth muscle cell models, elevated cGMP levels resulting from PDE5 inhibition activate cGMP-dependent protein kinase (PKG). PKG activation drives intracellular calcium sequestration and potassium channel activation, promoting smooth muscle hyperpolarization and vasodilation in tissue bath preparations.
N-Amino Diketopiperazine Binding Alterations: The presence of an N-amino group (-NH₂) attached to the diketopiperazine ring alters the polar surface area and hydrogen-bonding profile of the molecule compared to un-substituted or alkylated analogs, providing a valuable model for evaluating structure-activity relationships (SAR) across PDE enzymes.

What do Preclinical & Analytical Assays Show for Aminotadalafil?

When evaluating research efficacy and published scientific literature for Aminotadalafil:

In Vitro Enzyme Kinetics & cGMP Accumulation Assays: Enzymatic screening assays confirm that Aminotadalafil functions as a potent inhibitor of human recombinant PDE5. In isolated tissue models, exposure to Aminotadalafil induces a dose-dependent increase in tissue cGMP concentrations and potentiates nitric oxide-mediated relaxation curves.
Analytical Profiling & Mass Spectrometry Identification: Analytical research employing high-resolution mass spectrometry (HRMS) and multi-stage LC-MS/MS documents the distinctive fragmentation pathways of Aminotadalafil. The presence of the N-amino moiety yields characteristic product ions that serve as reference benchmarks during chromatographic adulteration screening and quality control assays.
Structure-Activity Relationship (SAR) Screening: Comparative binding studies evaluating β-carboline diketopiperazine derivatives show that modifying the diketopiperazine nitrogen atom directly influences metabolic degradation rates and receptor binding kinetics in hepatic and cellular fraction models.

How does Aminotadalafil compare to other compounds?

To evaluate chemical modifications, polar surface area, and receptor kinetics, researchers compare Aminotadalafil against related β-carboline analogs available at Modern Aminos:

Compound / Reference	Chemical Structure & Formula	Core Structural Modification	Research Profile & Focus
Aminotadalafil	C₂₁H₁₈N₄O₄ (MW 390.40 g/mol)	N-amino substitution on the diketopiperazine ring (-NH₂ group)	Focuses on PDE5 inhibition, increased polar surface area, and analytical reference profiling for N-amino substituted β-carbolines
Nortadalafil	C₂₁H₁₇N₃O₄ (MW 375.38 g/mol)	N-demethylated secondary amine structure (-NH group on diketopiperazine ring)	Focuses on evaluating un-substituted diketopiperazine hydrogen bonding, secondary amine lipophilicity, and demethylated metabolite pathway kinetics

Frequently Asked Questions (FAQs)

1. What is the structural classification of Aminotadalafil?

Aminotadalafil is a synthetic β-carboline derivative incorporating a fused pyrazinedione ring. Its defining structural feature is an amino group (-NH₂) attached to the nitrogen atom of the diketopiperazine ring, yielding the chemical formula C₂₁H₁₈N₄O₄.

2. How does Aminotadalafil modulate cGMP signaling in vitro?

Aminotadalafil competitively inhibits the phosphodiesterase type 5 (PDE5) enzyme. By blocking PDE5-mediated cGMP hydrolysis, Aminotadalafil maintains elevated cellular cGMP concentrations, supporting protein kinase G (PKG) activation and downstream nitric oxide-mediated vascular smooth muscle relaxation.

3. How does Aminotadalafil compare to Nortadalafil in chemical structure?

Aminotadalafil features an N-amino group (-NH₂) attached to the diketopiperazine ring nitrogen atom. In contrast, Nortadalafil is an N-desmethyl derivative possessing an un-substituted secondary amine (-NH) at that same nitrogen position, altering the molecular weight (390.40 g/mol vs 375.38 g/mol) and polar surface area.

4. What analytical testing methods are utilized for Aminotadalafil research?

Aminotadalafil is widely used as a certified reference standard in high-performance liquid chromatography (HPLC), liquid chromatography-mass spectrometry (LC-MS/MS), and nuclear magnetic resonance (NMR) spectroscopy. These methods establish baseline mass fragmentation patterns and retention times for analytical reference profiling. Read more about our Quality Assurance Program.

5. What are the storage and compliance parameters for Aminotadalafil at Modern Aminos?

Aminotadalafil provided by Modern Aminos is strictly for laboratory, in vitro, and analytical research use only (RUO). It is not approved for human or animal consumption. Solid reference samples should be stored sealed in a dry, dark place under frozen conditions (-20°C) to ensure long-term chemical stability.

The products offered by Modern Aminos are intended strictly for laboratory research purposes only and are sold exclusively to qualified professionals, institutions, and entities. These products are not for human consumption, veterinary use, or any other application involving living organisms, including but not limited to diagnostic, therapeutic, or recreational purposes.

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This product is not to be used as an active pharmaceutical ingredient (API) in compounding or manufacturing drugs for human or veterinary use.
It is strictly prohibited to use this product for administration to humans or animals under any circumstances.
Modern Aminos does not condone or permit the use of its products for the development, testing, or production of illegal substances.

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Modern Aminos does not claim that this product is approved by the U.S. Food and Drug Administration (FDA) for any purpose. The statements regarding this product have not been evaluated by the FDA. This product is not intended to diagnose, treat, cure, or prevent any disease.

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The buyer assumes full responsibility for ensuring the safe handling, storage, and use of this product. Modern Aminos is not liable for any damages, direct or indirect, resulting from improper handling, storage, or unauthorized use of this product. Furthermore, Modern Aminos reserves the right to refuse sales to any individual or entity suspected of misusing its products.

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