7-Bromooxindole Handling & Application Protocol

7-Bromooxindole is a brominated oxindole derivative widely used as a versatile building block in medicinal chemistry, heterocyclic synthesis, and the preparation of pharmacologically active scaffolds.

CAS Number

7477-35-2

Molecular Formula

C₈H₆BrNO

Molecular Weight

212.04 g/mol

Appearance

Off-white to pale yellow crystalline solid

Recommended Storage

Cool, dry place; protected from light and moisture

Primary Application

Synthetic building block for medicinal and heterocyclic chemistry

Materials and Safety Precautions

Before beginning any experimental work with 7-Bromooxindole (SKU: B151900), review the Safety Data Sheet (SDS) provided by Aladdin Scientific. The compound should be handled in a well-ventilated fume hood. Wear appropriate personal protective equipment (PPE) including nitrile gloves, a laboratory coat, and safety goggles.

Required materials include: 7-Bromooxindole (B151900), anhydrous organic solvents (e.g., DMSO, DMF, ethanol, or THF depending on application), analytical balance, amber glass vials for storage, inert gas line (nitrogen or argon) for moisture-sensitive applications, and standard laboratory glassware.

Avoid inhalation of dust and contact with skin or eyes. In case of contact, wash thoroughly with water and seek medical advice if irritation persists. Dispose of waste in accordance with local chemical waste regulations.

Stock Solution Preparation and Solubility

7-Bromooxindole is sparingly soluble in water but demonstrates good solubility in polar aprotic solvents such as DMSO and DMF, and moderate solubility in ethanol and THF. For most synthetic applications, anhydrous DMF or DMSO is recommended as the solvent of choice.

Preparation of a 100 mM Stock Solution in DMSO:

1. Accurately weigh the required amount of 7-Bromooxindole using a calibrated analytical balance. For a 1 mL stock at 100 mM, weigh approximately 21.2 mg.
2. Transfer the solid to a clean, dry amber glass vial.
3. Add the calculated volume of anhydrous DMSO and vortex or sonicate gently until complete dissolution is achieved.
4. Inspect the solution visually to confirm clarity. If any particulate remains, gently warm to 37 °C and re-vortex.
5. Aliquot into single-use volumes, seal under nitrogen or argon, and store at –20 °C protected from light.

Note: Repeated freeze-thaw cycles should be minimized to prevent degradation. Prepare fresh solutions when possible for sensitive applications.

Synthetic Applications and Reaction Protocol

7-Bromooxindole serves as a key building block in organic and medicinal chemistry. The bromine atom at the 7-position provides a reactive handle for a variety of transition-metal-catalyzed cross-coupling reactions, including Suzuki–Miyaura, Buchwald–Hartwig, and Ullmann-type couplings, enabling diversification of the oxindole scaffold.

General Guidance for Palladium-Catalyzed Cross-Coupling:

1. Combine 7-Bromooxindole (1.0 equiv.) with the appropriate coupling partner (e.g., arylboronic acid for Suzuki coupling, 1.2–1.5 equiv.) in a dry Schlenk flask or sealed vial under inert atmosphere.
2. Add a palladium catalyst (e.g., Pd(PPh₃)₄ or Pd(dppf)Cl₂, 2–5 mol%) and a suitable base (e.g., K₂CO₃ or Cs₂CO₃, 2.0 equiv.).
3. Add degassed solvent (e.g., DMF/H₂O 4:1 or dioxane) and heat the reaction mixture to 80–100 °C with stirring.
4. Monitor reaction progress by TLC or HPLC.
5. Upon completion, cool to room temperature, dilute with ethyl acetate, wash with brine, dry over anhydrous Na₂SO₄, filter, and concentrate under reduced pressure.
6. Purify the product by column chromatography (silica gel, appropriate eluent system).

Exact reaction conditions (catalyst loading, temperature, solvent, and time) should be optimized empirically for each specific transformation.

Storage, Stability, and Quality Control

7-Bromooxindole should be stored in a tightly sealed container in a cool, dry location away from light, heat, and moisture. Long-term storage at 2–8 °C or below is recommended to maintain compound integrity. Under recommended conditions, the compound is expected to be stable for at least 24 months from the date of manufacture; however, users should verify purity before use in critical experiments.

Quality Control Checks:

• Visual inspection: The compound should appear as an off-white to pale yellow solid. Significant darkening may indicate degradation.
• Melting point: Verify against the specification sheet value as an identity check.
• TLC analysis: Run a spot on silica gel TLC using an appropriate solvent system (e.g., 3:1 hexane/ethyl acetate) and compare Rf value against reference.
• NMR or HPLC purity: For high-stakes applications, confirm purity by ¹H NMR or reverse-phase HPLC (≥98% purity recommended).

If purity is found to be below specification, contact Aladdin Scientific technical support for assistance.

Frequently asked questions

What solvents are recommended for dissolving 7-Bromooxindole?

7-Bromooxindole dissolves well in polar aprotic solvents such as DMSO and DMF, and shows moderate solubility in ethanol and THF. It is sparingly soluble in water and generally not recommended for aqueous-only systems without a co-solvent.

What types of chemical reactions is 7-Bromooxindole commonly used in?

The compound is primarily used as a building block in transition-metal-catalyzed cross-coupling reactions such as Suzuki–Miyaura, Buchwald–Hartwig, and Ullmann-type couplings, leveraging the reactive C–Br bond at the 7-position. It is also employed in the synthesis of biologically active oxindole-containing heterocycles relevant to medicinal chemistry research.

How should 7-Bromooxindole be stored to ensure maximum shelf life?

Store 7-Bromooxindole in a tightly sealed, light-resistant container at 2–8 °C or below, in a cool and dry environment. Minimize exposure to moisture, heat, and light. For stock solutions, aliquot and store under inert gas at –20 °C to avoid repeated freeze-thaw cycles.

Is 7-Bromooxindole suitable for use in biological assays?

7-Bromooxindole is primarily a synthetic intermediate, but oxindole derivatives broadly are studied for biological activities in medicinal chemistry contexts. If used in cell-based or biochemical assays, ensure appropriate solvent controls are included and that the final DMSO concentration is within acceptable limits for the biological system under study.

References

1. Aladdin Scientific Product Page: 7-Bromooxindole, SKU B151900. Aladdin Scientific Corp.
2. March, J. Advanced Organic Chemistry: Reactions, Mechanisms, and Structure. 4th ed. Wiley-Interscience, 1992. (General reference for oxindole chemistry and cross-coupling reactions.)
3. Miyaura, N.; Suzuki, A. Palladium-Catalyzed Cross-Coupling Reactions of Organoboron Compounds. Chemical Reviews, 1995, 95(7), 2457–2483. doi:10.1021/cr00039a007

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.