5-Bromo-1-methylisatin: Synthesis, Handling & Application Protocol

5-Bromo-1-methylisatin is a brominated, N-methylated isatin derivative widely employed as a reactive heterocyclic building block in medicinal chemistry, organic synthesis, and the preparation of biologically active scaffolds.

CAS Number

Verify with Aladdin certificate of analysis (review flag: CAS not provided in source material)

Molecular Formula

C₉H₆BrNO₂

Molecular Weight

240.05 g/mol (review flag: confirm against CoA)

Appearance

Solid (typically orange to yellow crystalline powder; review flag: verify against CoA)

Recommended Storage

Store in a cool, dry place away from light and moisture; review flag: confirm exact temperature from CoA

SKU

B153063

Key Functional Groups

C-5 bromo substituent, N-1 methyl group, 1,2-diketone moiety (isatin core)

Overview and Chemical Background

5-Bromo-1-methylisatin (SKU: B153063) is a member of the isatin family—a class of naturally occurring and synthetically accessible oxindole-based heterocycles. The parent scaffold, isatin (1H-indole-2,3-dione), is a privileged structure in medicinal chemistry due to its broad range of biological activities, including reported enzyme inhibition and interaction with various biological targets.

Introducing a bromine atom at the C-5 position significantly modulates the electronic character of the ring, making it more electrophilic and enabling downstream cross-coupling reactions such as Suzuki–Miyaura, Sonogashira, and Buchwald–Hartwig couplings. The N-methyl group at position 1 prevents N–H tautomerism and protects the nitrogen, thus influencing both reactivity and lipophilicity. Together, these substitutions make 5-Bromo-1-methylisatin a versatile building block for constructing complex heterocyclic frameworks used in pharmaceutical lead discovery and materials science.

Review flag: Specific biological activity data for this exact compound were not present in the source material; all activity claims are general class-level statements requiring literature verification.

Safety and Handling Precautions

As with all brominated heterocyclic compounds, appropriate laboratory safety precautions must be observed when working with 5-Bromo-1-methylisatin. Always consult the current Safety Data Sheet (SDS) provided by Aladdin Scientific before use.

• Personal Protective Equipment (PPE): Wear nitrile gloves, a laboratory coat, and safety goggles at all times. Use a dust mask or appropriate respiratory protection when handling solid material to avoid inhalation of fine particles.
• Ventilation: Handle the compound inside a certified chemical fume hood.
• Skin and Eye Contact: In case of skin contact, wash thoroughly with soap and water. If contact with eyes occurs, rinse immediately with copious amounts of water and seek medical attention.
• Waste Disposal: Dispose of all waste, including solutions and contaminated materials, in accordance with local institutional and governmental regulations for halogenated organic waste.

Review flag: GHS hazard classification and specific hazard statements (H- and P-codes) for this compound were not provided in the source material and must be confirmed from the Aladdin SDS before use.

Solubility and Solution Preparation

Isatin derivatives, including N-alkylated and halogenated analogues, are generally sparingly soluble in water but display improved solubility in polar aprotic solvents. The following guidance is based on general class properties; confirm experimentally for your specific application.

Recommended Solvents

• DMSO: The preferred solvent for most biochemical assays. Prepare a concentrated stock solution (e.g., 10–100 mM) in anhydrous DMSO, then dilute into aqueous assay buffer to a final DMSO concentration ≤0.1% v/v to minimize solvent effects on biological systems.
• DMF or NMP: Suitable for synthetic applications where protic solvents are undesirable.
• Ethanol or methanol: May provide partial solubility and can be used for some synthetic procedures.
• Dichloromethane (DCM) or ethyl acetate: Useful for extraction, purification, and chromatographic applications.

Preparation Protocol

1. Weigh the required mass of 5-Bromo-1-methylisatin on an analytical balance in a fume hood.
2. Transfer quantitatively to an appropriate glass vial.
3. Add the chosen solvent incrementally with gentle vortex mixing or sonication until fully dissolved.
4. For aqueous dilution, add warm aqueous buffer dropwise to the organic stock solution while stirring to prevent precipitation.
5. Filter through a 0.22 µm syringe filter if required for biological assays.
6. Prepare fresh solutions or store aliquots at −20 °C under inert atmosphere (nitrogen or argon) to prevent moisture uptake and degradation.

Review flag: Exact solubility values (mg/mL) were not provided in the source material; solubility data should be confirmed experimentally or sourced from the Aladdin product datasheet.

Application in Organic Synthesis

5-Bromo-1-methylisatin serves as a multifunctional electrophilic building block in synthetic organic chemistry. Key applications include:

1. Palladium-Catalyzed Cross-Coupling

The C-5 aryl bromide is amenable to standard Pd-catalyzed cross-coupling reactions. For example:

• Suzuki–Miyaura coupling: React with aryl or heteroaryl boronic acids using Pd(PPh₃)₄ or Pd(dppf)Cl₂ as catalyst, K₂CO₃ or Cs₂CO₃ as base, in DMF/H₂O or dioxane/H₂O at 80–100 °C.
• Sonogashira coupling: React with terminal alkynes using Pd/Cu co-catalysis in amine solvents (triethylamine or diisopropylamine) at room temperature to 60 °C.

2. Nucleophilic Addition to the 3-Keto Position

The electrophilic C-3 carbonyl of the isatin core undergoes nucleophilic addition with amines, hydrazines, hydroxylamines, and active methylene compounds to yield oxime, hydrazone, Schiff base, and spiro-fused heterocyclic products, respectively.

3. Multicomponent Reactions (MCRs)

Isatin derivatives are widely used in three-component and Groebke–Blackman–Bienaymé-type reactions to rapidly generate structurally diverse, drug-like heterocyclic libraries. 5-Bromo-1-methylisatin can participate as the carbonyl component.

Review flag: Specific yield and condition data for these transformations with this exact substrate were not provided in the source material; literature precedent should be consulted for optimization.

Quality Control and Storage Recommendations

Proper storage and quality verification are essential for reproducible experimental results when using 5-Bromo-1-methylisatin.

Quality Control

• Verify compound identity and purity using the Aladdin Certificate of Analysis (CoA), which includes purity data typically determined by HPLC or GC.
• Confirm structural identity by comparison of ¹H NMR, ¹³C NMR, and MS data against literature values or reference spectra.
• For critical applications, re-analyze purity in-house by HPLC prior to use.

Storage Conditions

• Store in a tightly sealed container in a cool, dry, well-ventilated location away from direct light.
• Keep away from incompatible materials, including strong bases, strong oxidizing agents, and reducing agents.
• Recommended storage temperature: refer to Aladdin CoA or product label (review flag: specific temperature not stated in source material).
• After opening, reseal under inert gas (N₂ or Ar) and store desiccated to prevent hydrolysis and oxidative degradation.

Shelf Life

When stored under appropriate conditions, the compound is expected to be stable for an extended period; however, the exact shelf life should be confirmed from the Aladdin product datasheet. Discard any material showing discoloration or changes in physical appearance beyond the stated specification.

Review flag: Exact shelf life and confirmed storage temperature for B153063 were not provided in the source material.

Frequently asked questions

What solvents are suitable for dissolving 5-Bromo-1-methylisatin?

5-Bromo-1-methylisatin is best dissolved in polar aprotic solvents such as DMSO or DMF. For biological assays, prepare a concentrated stock in DMSO and dilute into aqueous buffer to keep final DMSO concentration below 0.1% v/v. Solubility in water alone is expected to be low; confirm exact values experimentally or from the Aladdin product datasheet.

Can 5-Bromo-1-methylisatin be used in palladium-catalyzed cross-coupling reactions?

Yes. The C-5 aryl bromide is a competent electrophile for Pd-catalyzed reactions including Suzuki–Miyaura coupling with boronic acids and Sonogashira coupling with terminal alkynes. Standard Pd catalysts (e.g., Pd(PPh₃)₄, Pd(dppf)Cl₂) and bases (K₂CO₃, Cs₂CO₃) are recommended as starting points; conditions should be optimized for each specific substrate pair.

How should I store 5-Bromo-1-methylisatin to maintain its stability?

Store 5-Bromo-1-methylisatin in a tightly sealed container under inert atmosphere in a cool, dry, dark location. After opening, reseal under nitrogen or argon and consider using a desiccant to minimize moisture exposure. Always consult the Aladdin Certificate of Analysis for the confirmed storage temperature specific to batch B153063.

What is the difference between isatin and 5-Bromo-1-methylisatin?

Isatin (1H-indole-2,3-dione) is the unsubstituted parent heterocycle with a free N–H group. 5-Bromo-1-methylisatin differs by having a methyl group on the nitrogen (N-1), which eliminates N–H reactivity and increases lipophilicity, and a bromine atom at C-5, which activates the ring toward cross-coupling reactions and alters the electronic properties of the carbonyl groups.

Is 5-Bromo-1-methylisatin available from Aladdin Scientific and what is the SKU?

Yes, 5-Bromo-1-methylisatin is available from Aladdin Scientific under SKU B153063. Please visit the Aladdin website or contact customer service for current pricing, available pack sizes, and stock availability.

References

1. Vine, K.L. et al. An investigation into the cytotoxicity and mode of action of some novel N-alkyl-substituted isatins. Journal of Medicinal Chemistry. (General reference for N-alkylisatin biological activity — specific article details require verification)
2. Dömling, A.; Ugi, I. Multicomponent reactions with isocyanides. Angewandte Chemie International Edition. 2000, 39, 3168–3210. (General MCR reference; applicability to isatin derivatives requires confirmation) doi:10.1002/1521-3773(20001103)39:21<3168::AID-ANIE3168>3.0.CO;2-U
3. Clayden, J.; Greeves, N.; Warren, S. Organic Chemistry, 2nd ed.; Oxford University Press: Oxford, 2012. (Textbook-level reference for cross-coupling reaction conditions)

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