Methyl 3-Aminothieno[2,3-c]pyridine-2-Carboxylate: Lab Protocol

Methyl 3-aminothieno[2,3-c]pyridine-2-carboxylate is a bifunctional thienopyridine heterocycle featuring a free primary amine and an ester group, making it a versatile building block for the synthesis of fused-ring pharmaceutically relevant scaffolds.

Chemical Name

Methyl 3-aminothieno[2,3-c]pyridine-2-carboxylate

SKU

M700637

Core Scaffold

Thienopyridine (thieno[2,3-c]pyridine)

Key Functional Groups

Primary amine (–NH₂) at C-3; methyl ester (–CO₂Me) at C-2

Primary Application

Heterocyclic synthesis intermediate; medicinal chemistry scaffold

Recommended Storage

Cool, dry, well-ventilated area; away from moisture and light; refer to SDS for full conditions

Compound Overview and Chemical Properties

Methyl 3-aminothieno[2,3-c]pyridine-2-carboxylate (Aladdin SKU: M700637) is a bicyclic heteroaromatic compound in which a thiophene ring is fused to a pyridine ring in the [2,3-c] orientation. The molecule carries two synthetically valuable functional groups: a primary amino group at the 3-position of the thiophene ring and a methyl ester at the 2-position. This combination imparts high reactivity toward electrophilic acylation, condensation, and cyclization reactions, enabling rapid assembly of tricyclic and polycyclic heterocyclic frameworks of interest in drug discovery.

The thienopyridine scaffold is a privileged structure found in several bioactive molecules, including kinase inhibitors and anti-infective agents. The [2,3-c] ring fusion pattern positions the sulfur and nitrogen atoms in a geometry that influences electronic delocalization, hydrogen-bond acceptor capacity, and overall molecular planarity, all of which are important parameters in structure–activity relationship studies.

Materials and Safety Precautions

Materials required:

• Methyl 3-aminothieno[2,3-c]pyridine-2-carboxylate (M700637, Aladdin Scientific)
• Appropriate organic solvents (e.g., DMSO, DMF, dichloromethane, or ethanol) for dissolution
• Analytical balance (0.1 mg readability)
• Volumetric glassware and amber vials for stock solutions
• Personal protective equipment (PPE): laboratory coat, nitrile gloves, safety goggles

Safety precautions: As with all fine chemical reagents, handle Methyl 3-aminothieno[2,3-c]pyridine-2-carboxylate in a well-ventilated fume hood. Avoid inhalation of dust and contact with skin, eyes, and clothing. Consult the Safety Data Sheet (SDS) provided by Aladdin Scientific before use for complete hazard information, first-aid measures, and disposal guidelines. Specific toxicological data for this compound should be confirmed from the SDS, as detailed data are not included in this document.

Step-by-Step Protocol: Dissolution and Stock Solution Preparation

Follow the steps below to prepare a working stock solution of Methyl 3-aminothieno[2,3-c]pyridine-2-carboxylate for use in synthetic or analytical procedures:

1. Equilibrate to room temperature: Remove the reagent vial from cold storage and allow it to equilibrate to ambient temperature before opening to prevent moisture condensation on the solid.
2. Weigh the compound: Using a calibrated analytical balance, accurately weigh the required amount of compound into a tared vessel inside a fume hood.
3. Select an appropriate solvent: DMSO and DMF are generally good choices for dissolving polar heterocyclic compounds. For reactions requiring aprotic conditions, DMF or dichloromethane may be preferred. Verify compatibility with your downstream reaction before proceeding.
4. Dissolve the compound: Add the chosen solvent gradually to the weighed compound with gentle swirling or brief vortexing until complete dissolution is achieved. If dissolution is slow, brief mild warming (do not exceed 40 °C) may assist.
5. Prepare the stock solution: Transfer the solution to an amber vial and label with compound name, SKU, concentration, solvent, date of preparation, and preparer's initials.
6. Aliquot and store: Aliquot as needed to avoid repeated freeze–thaw cycles. Store according to SDS recommendations, typically in a cool, dry place, protected from light and moisture. Seal vials under inert gas (nitrogen or argon) if prolonged storage is anticipated.

Note: Exact solubility data for this specific compound should be confirmed experimentally or from the product specification sheet, as values can vary with purity and lot.

Synthetic Applications and Reaction Guidance

Methyl 3-aminothieno[2,3-c]pyridine-2-carboxylate is primarily used as a heteroaromatic building block in multi-step synthesis. The following reaction pathways are well precedented for analogous 3-amino-2-ester thiophene systems and are relevant starting points for designing synthetic routes:

• Amide bond formation: The free amine at C-3 can be acylated with acid chlorides or activated esters to generate amide derivatives. This reaction is typically performed in the presence of a base (e.g., triethylamine) in an aprotic solvent such as dichloromethane or THF at 0 °C to room temperature.
• Cyclization to thienopyridinones or related fused systems: Treatment with bifunctional electrophiles (e.g., α,β-unsaturated carbonyl compounds, ortho esters, or isocyanates) can promote cyclization of the amine and ester groups to yield tricyclic lactam or iminolactone structures.
• Ester hydrolysis and decarboxylative functionalization: The methyl ester can be hydrolyzed under standard basic conditions (e.g., LiOH, aqueous THF) to give the corresponding carboxylic acid, which may undergo further functionalization including coupling reactions or decarboxylation.
• Cross-coupling reactions: Depending on the substitution pattern introduced in subsequent steps, palladium-catalyzed cross-coupling reactions (Suzuki, Buchwald–Hartwig) may be applicable on derived halogenated intermediates.

Researchers should consult primary literature for specific reaction conditions applicable to thienopyridine systems, and validate conditions experimentally. Specific yields and conditions are not guaranteed and should be optimized on a case-by-case basis.

Storage, Stability, and Quality Considerations

Storage: Store Methyl 3-aminothieno[2,3-c]pyridine-2-carboxylate in a tightly sealed container in a cool, dry, and well-ventilated area, protected from direct light and atmospheric moisture. Refer to the SDS and product specification sheet (available from Aladdin Scientific) for lot-specific storage temperature recommendations.

Stability: Thienopyridine heterocycles with a free amino group may be susceptible to oxidative degradation or dimerization upon prolonged exposure to air and light. For best results, use freshly opened material or material stored under inert atmosphere. Solutions should be prepared freshly where possible, or stored as described above.

Quality control: Aladdin Scientific's M700637 is supplied with purity information. Users are encouraged to verify purity by HPLC or NMR prior to use in sensitive assays. Lot-specific certificates of analysis (CoA) are available upon request.

Disposal: Dispose of unused material and contaminated solvents in accordance with local environmental regulations and institutional guidelines. Do not dispose of down the drain.

Frequently asked questions

What solvents are recommended for dissolving Methyl 3-aminothieno[2,3-c]pyridine-2-carboxylate?

Polar aprotic solvents such as DMSO and DMF are generally recommended as first-choice solvents for dissolving heteroaromatic amino ester compounds of this type. Dichloromethane and ethanol may also be suitable depending on the downstream application. Exact solubility should be confirmed experimentally using the specific lot.

How should I store Methyl 3-aminothieno[2,3-c]pyridine-2-carboxylate to maintain its integrity?

Store the compound in a tightly sealed container in a cool, dry, and well-ventilated location, away from light, heat, and moisture. If long-term storage is required, consider sealing vials under an inert gas such as nitrogen or argon. Always consult the SDS for authoritative storage conditions.

What synthetic transformations can be performed with the amino and ester groups of this compound?

The primary amine at C-3 is amenable to acylation, sulfonylation, reductive amination, and cyclization reactions, while the methyl ester at C-2 can be hydrolyzed to the carboxylic acid, converted to amides via aminolysis, or reduced to the alcohol. Combined, these groups enable formation of fused tricyclic ring systems through intramolecular cyclization, making this compound a versatile intermediate in medicinal chemistry.

How do I confirm the purity of the compound before use in sensitive assays?

Purity can be verified by reverse-phase HPLC using a UV detector (monitoring at an appropriate wavelength, commonly 254 nm or 280 nm) and confirmed by ¹H NMR and ¹³C NMR spectroscopy. A Certificate of Analysis (CoA) for the specific lot is available from Aladdin Scientific upon request and provides the reference purity value.

References

1. Aladdin Scientific. Product page: Methyl 3-aminothieno[2,3-c]pyridine-2-carboxylate, SKU M700637. Aladdin Scientific, Shanghai.
2. Joule, J. A.; Mills, K. Heterocyclic Chemistry, 5th ed.; Wiley-Blackwell: Oxford, 2010. (General reference for thienopyridine chemistry.)
3. Kappe, C. O. Biologically active dihydropyrimidones of the Biginelli-type — a literature survey. Eur. J. Med. Chem. 2000, 35, 1043–1052. (General reference for heterocyclic building blocks in medicinal chemistry; not specific to this compound.) doi:10.1016/S0223-5234(00)01186-3

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