5-Chloro-6-methoxy-1H-pyrrolo[2,3-b]pyridine: Handling & Use Protocol
5-Chloro-6-methoxy-1H-pyrrolo[2,3-b]pyridine: Handling & Use Protocol
5-chloro-6-methoxy-1H-pyrrolo[2,3-b]pyridine is a halogenated, methoxy-substituted 7-azaindole derivative widely employed as a versatile heterocyclic building block in the synthesis of kinase inhibitors and other bioactive small molecules.
- Chemical Name
- 5-chloro-6-methoxy-1H-pyrrolo[2,3-b]pyridine
- Aladdin SKU
- C627194
- Core Scaffold
- 7-azaindole (pyrrolo[2,3-b]pyridine)
- Key Substituents
- 5-chloro, 6-methoxy
- Primary Application
- Medicinal chemistry building block; kinase inhibitor synthesis
- Recommended Storage
- Cool, dry, dark conditions; tightly sealed container
Materials and Safety Precautions
Before beginning, assemble the following materials: 5-chloro-6-methoxy-1H-pyrrolo[2,3-b]pyridine (Aladdin SKU C627194), anhydrous dimethyl sulfoxide (DMSO) or dimethylformamide (DMF) for stock solution preparation, analytical balance, amber vials, inert-gas (N₂ or Ar) supply, and appropriate personal protective equipment (PPE).
Safety: As with all halogenated heterocyclic compounds, treat this reagent with appropriate caution. Wear nitrile gloves, a laboratory coat, and safety goggles. Handle in a well-ventilated fume hood. Avoid inhalation of dust or aerosols. Consult the product Safety Data Sheet (SDS) for full hazard information before use. Dispose of waste in accordance with local regulations for halogenated organic compounds.
Stock Solution Preparation
5-chloro-6-methoxy-1H-pyrrolo[2,3-b]pyridine exhibits good solubility in polar aprotic solvents such as DMSO and DMF. The following procedure is recommended for preparing a stock solution:
- Allow the sealed vial to equilibrate to room temperature before opening to prevent moisture condensation on the solid.
- Accurately weigh the required amount of compound on an analytical balance inside a fume hood.
- Transfer the solid to a clean, dry amber vial and add the appropriate volume of anhydrous DMSO or DMF to achieve the desired stock concentration (e.g., 10–100 mM).
- Vortex or gently sonicate until complete dissolution is confirmed visually.
- Aliquot into single-use volumes to avoid repeated freeze-thaw cycles.
- Seal vials under an inert atmosphere (N₂ or Ar), label clearly with compound name, SKU, concentration, solvent, date, and preparer's initials.
- Store aliquots at −20 °C or as specified in the product datasheet.
Note: Verify solubility in your specific assay buffer or co-solvent system empirically, as matrix effects may reduce effective solubility.
Application in Synthetic and Biological Assays
The 7-azaindole (pyrrolo[2,3-b]pyridine) scaffold is a well-established pharmacophore in drug discovery, and the 5-chloro and 6-methoxy substituents provide handles for further functionalization and modulate electronic and steric properties of the core.
Synthetic applications: The C-5 chloro substituent can serve as a leaving group in transition-metal-catalyzed cross-coupling reactions (e.g., Suzuki–Miyaura, Buchwald–Hartwig amination), enabling rapid diversification of the scaffold. The NH of the pyrrole ring may require protection (e.g., with a Boc or SEM group) prior to N-functionalization reactions, depending on the synthetic sequence.
Biological screening: When using DMSO stock solutions in cell-based or biochemical assays, dilute into aqueous assay buffer immediately before use and ensure the final DMSO concentration does not exceed 0.1–1% (v/v) to avoid solvent cytotoxicity. Prepare fresh dilutions for each experiment. Include appropriate vehicle controls in all assays.
Specific reaction conditions, yields, and biological activity data are not provided in this protocol; consult primary literature for application-specific parameters.
Quality Control and Characterization
Upon receipt of 5-chloro-6-methoxy-1H-pyrrolo[2,3-b]pyridine (SKU C627194) from Aladdin Scientific, perform the following identity and purity checks before committing material to experiments:
- Visual inspection: The compound should appear as a solid (color may vary by lot; consult Certificate of Analysis). Discard any lot showing discoloration, caking, or signs of moisture uptake inconsistent with CoA description.
- TLC or HPLC purity check: Confirm purity against the Certificate of Analysis (CoA) specification using an appropriate reverse-phase HPLC method or TLC system.
- MS confirmation: Verify molecular ion consistent with the molecular formula by ESI-MS or APCI-MS.
- NMR (if required): ¹H NMR in DMSO-d₆ or CDCl₃ can confirm structural integrity; compare to literature or CoA reference spectra.
Retain the CoA and maintain a usage log (date, amount used, lot number, experiment ID) for GLP compliance and traceability.
Troubleshooting
The following troubleshooting guidance addresses common issues encountered when working with this compound:
| Issue | Possible Cause | Recommended Action |
|---|---|---|
| Incomplete dissolution in DMSO | Moisture contamination or degradation of material | Use freshly opened anhydrous DMSO; gently warm to 37 °C and re-vortex; verify lot purity via CoA |
| Precipitate in aqueous assay buffer | Aqueous solubility exceeded; DMSO dilution too rapid | Reduce compound concentration; add buffer dropwise while mixing; use co-solvent (e.g., PEG-400) if compatible with assay |
| Unexpected side products in coupling reactions | NH not protected; competing N-arylation | Protect NH prior to C–C or C–N coupling steps; optimize base and temperature |
| Compound degradation on storage | Moisture, light, or thermal exposure | Ensure storage under inert atmosphere at recommended temperature; avoid repeated freeze-thaw cycles |
Frequently asked questions
What solvents are recommended for dissolving 5-chloro-6-methoxy-1H-pyrrolo[2,3-b]pyridine?
Anhydrous DMSO and DMF are the recommended solvents for preparing concentrated stock solutions of this compound. For downstream aqueous assays, dilute the DMSO stock into the appropriate buffer immediately before use, keeping the final DMSO concentration at or below 1% (v/v) to minimize solvent effects.
How should 5-chloro-6-methoxy-1H-pyrrolo[2,3-b]pyridine (C627194) be stored to maintain stability?
The compound should be stored in a tightly sealed container under an inert atmosphere (nitrogen or argon) in a cool, dry, and dark environment. Stock solutions in DMSO should be aliquoted to avoid repeated freeze-thaw cycles and stored at −20 °C. Always allow vials to equilibrate to room temperature before opening to prevent moisture condensation.
What is the significance of the 5-chloro substituent in this compound for synthetic chemistry?
The 5-chloro group serves as a versatile handle for transition-metal-catalyzed cross-coupling reactions, including Suzuki–Miyaura, Buchwald–Hartwig, and related transformations, enabling introduction of diverse aryl, heteroaryl, or amino substituents at the C-5 position. This makes the compound a valuable building block for generating structurally diverse libraries of pyrrolopyridine-based molecules.
Does the pyrrole NH in 5-chloro-6-methoxy-1H-pyrrolo[2,3-b]pyridine require protection during synthesis?
Whether NH protection is required depends on the specific synthetic transformation being performed. For reactions at C-5 (e.g., palladium-catalyzed coupling) where the NH may interfere with the catalyst or undergo competing N-functionalization, temporary protection with groups such as Boc, SEM, or PMB is advisable. Consult primary literature for your specific reaction conditions.
References
- Aladdin Scientific. Product Certificate of Analysis: 5-chloro-6-methoxy-1H-pyrrolo[2,3-b]pyridine, SKU C627194. Aladdin Scientific Corp.
- Comprehensive Medicinal Chemistry III, Elsevier. Chapters on azaindole and pyrrolopyridine scaffolds in kinase inhibitor design. (General reference — specific edition and page numbers to be confirmed.)
- Clayden, J.; Greeves, N.; Warren, S. Organic Chemistry, 2nd ed.; Oxford University Press: Oxford, 2012. Chapters on transition-metal-catalyzed cross-coupling reactions.
Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.
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