4-Chlorothieno[3,2-c]pyridine: Properties & Applications

4-Chlorothieno[3,2-c]pyridine is a bicyclic heteroaromatic building block featuring a thiophene ring fused to a pyridine ring with a reactive chloro substituent at the 4-position, making it a versatile intermediate in the synthesis of pharmacologically active compounds.

Chemical Name

4-Chlorothieno[3,2-c]pyridine

SKU

C124450

Core Scaffold

Thienopyridine bicyclic system (thiophene fused to pyridine)

Key Functional Group

Chloro substituent at position 4, amenable to nucleophilic aromatic substitution and cross-coupling reactions

Primary Use

Synthetic building block in medicinal chemistry and drug discovery

Supplier

Aladdin Scientific

Chemical Structure and Properties

4-Chlorothieno[3,2-c]pyridine belongs to the thienopyridine class of fused bicyclic heterocycles, in which a thiophene ring is annulated to a pyridine ring in the [3,2-c] fusion pattern. This specific fusion regiochemistry places the sulfur atom of the thiophene adjacent to the nitrogen-bearing carbon of the pyridine, resulting in a planar, electron-deficient aromatic system.

The chloro group at the 4-position is positioned on the pyridine-derived portion of the bicycle. This placement renders the carbon bearing the chlorine highly electrophilic, facilitating participation in nucleophilic aromatic substitution (SNAr) reactions with amines, alcohols, and thiols, as well as transition-metal-catalyzed cross-coupling reactions such as Suzuki–Miyaura, Buchwald–Hartwig, and Negishi couplings.

As a heteroaromatic compound, 4-Chlorothieno[3,2-c]pyridine exhibits the characteristic physical properties of fused bicyclic systems, including a relatively high degree of planarity, potential for π–π stacking interactions, and moderate lipophilicity that is relevant to drug-likeness assessments.

Synthesis and Reactivity

The thienopyridine scaffold can be accessed via several classical heterocyclic synthesis strategies. Common approaches include cyclization of appropriately substituted aminothiophene or cyanothiophene precursors, Gewald-type reactions, and directed C–H functionalization of simpler pyridine or thiophene precursors. The introduction of the chloro substituent at the 4-position is typically achieved through electrophilic chlorination or, more commonly, via treatment of the corresponding hydroxyl (oxo) precursor with phosphorus oxychloride (POCl₃), a well-established method for converting lactam-type heterocycles into their chloro analogs.

Once obtained, the C–Cl bond at the 4-position serves as a handle for diverse downstream transformations. Palladium-catalyzed coupling reactions allow installation of aryl, heteroaryl, vinyl, or alkyl groups, greatly expanding structural diversity around the thienopyridine core. SNAr displacement with nitrogen nucleophiles such as primary and secondary amines is particularly useful for generating aminothienopyridine analogs relevant to kinase inhibitor programs.

Researchers should note that the electron-deficient nature of the ring system may influence reaction rates and selectivity in both coupling and substitution chemistry; appropriate optimization of base, solvent, ligand, and temperature is recommended.

Applications in Drug Discovery and Medicinal Chemistry

Thienopyridine-containing compounds represent a well-recognized pharmacophore class in drug discovery. The fused bicyclic heteroaromatic scaffold provides a rigid, planar framework that is well-suited for binding to enzyme active sites, particularly kinase ATP-binding pockets, where aromatic stacking and hydrogen-bond interactions with hinge-region residues are critical for potency and selectivity.

4-Chlorothieno[3,2-c]pyridine is consequently employed as a privileged building block in the synthesis of kinase inhibitor candidates, as well as other biologically active targets including anti-infective, anti-inflammatory, and anticancer agents. The reactive chloro group enables rapid library synthesis via parallel chemistry, supporting structure–activity relationship (SAR) campaigns in hit-to-lead and lead optimization phases of drug discovery.

Beyond kinase inhibition, thienopyridine scaffolds have been explored in the context of antiviral and antimicrobial agents, reflecting the broad utility of the heterocyclic core. Researchers in fragment-based drug discovery (FBDD) also value compact heteroaromatic fragments such as this for their favorable physicochemical properties and ease of elaboration.

Handling, Storage, and Safety Considerations

As with most heteroaromatic chlorides, 4-Chlorothieno[3,2-c]pyridine should be handled in accordance with standard laboratory safety practices. Gloves, safety glasses, and a laboratory coat are recommended as minimum personal protective equipment. Operations involving significant quantities or prolonged exposure should be conducted in a well-ventilated fume hood.

The compound should be stored in a tightly sealed container, protected from moisture and light, at cool temperatures as specified on the product label and Safety Data Sheet (SDS). Chlorinated heterocycles can be susceptible to hydrolysis under strongly acidic or basic aqueous conditions; anhydrous storage conditions help maintain purity and stability over time.

Researchers are advised to consult the product SDS provided by Aladdin Scientific for detailed hazard classifications, first-aid measures, and disposal guidelines prior to use. All waste containing this compound should be disposed of in accordance with applicable local and national regulations for chemical waste.

Why Choose Aladdin Scientific for C124450

Aladdin Scientific offers 4-Chlorothieno[3,2-c]pyridine (SKU: C124450) as part of its extensive catalog of heterocyclic building blocks and specialty reagents designed to support modern drug discovery and synthetic chemistry research. Aladdin's quality control processes are designed to ensure consistent purity and reliable batch-to-batch reproducibility, which is essential for SAR studies and reproducible synthetic workflows.

The compound is available for direct online ordering, with detailed product specifications, safety documentation, and technical support accessible through the Aladdin Scientific website. Bulk quantities and custom packaging options may be available upon request, making Aladdin Scientific a flexible partner for both academic research groups and industrial medicinal chemistry teams.

For procurement inquiries, pricing, and availability, researchers and lab managers are encouraged to contact Aladdin Scientific's sales and technical support teams directly.

Frequently asked questions

What reactions can be performed with the 4-chloro group on 4-Chlorothieno[3,2-c]pyridine?

The 4-chloro substituent can undergo nucleophilic aromatic substitution (SNAr) with nucleophiles such as amines, alcohols, and thiols. It is also compatible with palladium-catalyzed cross-coupling reactions including Suzuki–Miyaura, Buchwald–Hartwig amination, and Negishi coupling, enabling installation of diverse aryl, heteroaryl, and alkyl substituents.

What is the significance of the thienopyridine scaffold in drug discovery?

Thienopyridine scaffolds are recognized privileged structures in medicinal chemistry due to their planar, rigid bicyclic framework, which facilitates binding to enzyme active sites such as kinase ATP-binding pockets. They have been incorporated into kinase inhibitors, antiviral, antimicrobial, and anticancer drug candidates, making them highly versatile pharmacophores.

How should 4-Chlorothieno[3,2-c]pyridine (C124450) be stored to maintain stability?

The compound should be stored in a tightly sealed container under cool, dry, and dark conditions as indicated on the product label and SDS. Protecting the compound from moisture is particularly important, as chlorinated heterocycles can be susceptible to hydrolysis under aqueous conditions. Always refer to the Aladdin Scientific SDS for specific storage temperature recommendations.

Is 4-Chlorothieno[3,2-c]pyridine suitable for fragment-based drug discovery (FBDD)?

Yes, compact heteroaromatic fragments such as 4-Chlorothieno[3,2-c]pyridine are valued in fragment-based drug discovery for their favorable physicochemical properties, including moderate molecular weight, planarity, and ease of structural elaboration via the reactive chloro substituent. They serve as efficient starting points for growing or linking fragment hits into potent lead compounds.

References

1. Joule, J. A.; Mills, K. Heterocyclic Chemistry, 5th ed.; Wiley-Blackwell: Oxford, 2010. General reference for thienopyridine synthesis and reactivity.
2. Meanwell, N. A. Synopsis of Some Recent Tactical Application of Bioisosteres in Drug Design. J. Med. Chem. 2011, 54, 2529–2591. Discusses heteroaromatic scaffolds including thienopyridines in medicinal chemistry. doi:10.1021/jm1013693
3. Aladdin Scientific Product Page: 4-Chlorothieno[3,2-c]pyridine, SKU C124450. Aladdin Scientific, accessed 2024.

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