1-Benzyl-1H-indole: Properties, Uses & FAQs

1-Benzyl-1H-indole is a nitrogen-containing heterocyclic compound in which the indole nitrogen is alkylated with a benzyl group, making it a versatile N-protected indole building block widely employed in organic synthesis and medicinal chemistry research.

IUPAC Name

1-benzyl-1H-indole

Molecular Formula

C₁₅H₁₃N

Molecular Weight

207.27 g/mol

CAS Number

3229-16-1

Aladdin SKU

B690479

Compound Class

N-substituted indole (heterocyclic aromatic amine)

Primary Application

Synthetic intermediate and building block in organic and medicinal chemistry

What Is 1-Benzyl-1H-indole?

1-Benzyl-1H-indole (CAS 3229-16-1, Aladdin SKU B690479) is an N-substituted indole in which a benzyl group is attached to the nitrogen atom (position 1) of the indole ring system. The molecular formula is C₁₅H₁₃N with a molecular weight of approximately 207.27 g/mol.

The indole core is a bicyclic aromatic system consisting of a benzene ring fused to a pyrrole ring. N-benzylation blocks the reactive nitrogen, modifying the compound's reactivity profile and enabling selective functionalization at other ring positions, particularly C-2 and C-3.

This compound is commonly used as a reference standard, a synthetic intermediate, and a model substrate for exploring indole chemistry in academic and industrial research laboratories.

Physicochemical Properties and Handling

1-Benzyl-1H-indole is typically a pale yellow to off-white solid or low-melting solid at room temperature. It is soluble in common organic solvents such as dichloromethane, ethanol, acetone, and ethyl acetate, but has limited solubility in water due to its largely hydrophobic structure.

Storage recommendations for N-substituted indoles generally include keeping the compound in a cool, dry, well-ventilated area away from strong oxidizing agents and direct light. Containers should be kept tightly sealed to prevent moisture uptake and potential oxidation.

Standard laboratory personal protective equipment (PPE) — including chemical-resistant gloves, safety glasses, and a laboratory coat — should be worn when handling this compound. Consult the Safety Data Sheet (SDS) provided by Aladdin Scientific for complete hazard information before use.

Synthesis and Role as a Building Block

1-Benzyl-1H-indole is most commonly prepared by N-alkylation of indole with benzyl halides (e.g., benzyl bromide or benzyl chloride) under basic conditions. Phase-transfer catalysis or the use of inorganic bases such as potassium carbonate in polar aprotic solvents are frequently reported strategies.

Once the nitrogen is benzylated, the C-3 position of the indole remains highly nucleophilic and can participate in Friedel-Crafts-type reactions, Mannich reactions, and various electrophilic substitutions. The benzyl protecting group can later be removed by hydrogenolysis (e.g., Pd/C under H₂), restoring the free N-H indole if required.

As a building block, 1-benzyl-1H-indole finds application in the synthesis of indole alkaloid analogues, pharmaceutical intermediates, and ligands for biological studies. Researchers also employ it as a substrate to benchmark new C-H functionalization or transition-metal-catalyzed methodologies.

Applications in Research and Medicinal Chemistry

The indole scaffold is among the most prevalent heterocycles in approved pharmaceuticals and natural products. N-benzyl substitution provides a handle that subtly modulates lipophilicity, steric environment, and binding geometry when screening compound libraries.

1-Benzyl-1H-indole and its derivatives have been investigated in the context of receptor binding studies, enzyme inhibition assays, and as core fragments in structure-activity relationship (SAR) campaigns targeting a variety of biological pathways.

In materials and dye chemistry, N-substituted indoles serve as chromophore precursors and fluorescent probes. The benzyl group can also direct regioselectivity in photochemical reactions, expanding the utility of this compound beyond classical medicinal chemistry.

Ordering and Quality Information

Aladdin Scientific supplies 1-Benzyl-1H-indole under SKU B690479. The product is intended for research and development use only and is not for human or veterinary medicinal use.

Customers are encouraged to verify purity specifications, lot-specific certificates of analysis (CoA), and SDS documentation on the Aladdin Scientific website or by contacting customer service before placing an order. Bulk quantities and custom packaging may be available upon request.

For storage and shelf-life guidance, refer to the product label and CoA. Proper inventory management practices — including first-in, first-out rotation and regular inspection of container integrity — help maintain reagent quality throughout the lifecycle of the material.

Frequently asked questions

What is the CAS number for 1-Benzyl-1H-indole?

The CAS registry number for 1-Benzyl-1H-indole is 3229-16-1. Aladdin Scientific lists this compound under SKU B690479.

How is 1-Benzyl-1H-indole typically synthesized in the laboratory?

The most common route is N-alkylation of indole with a benzyl halide (benzyl bromide or benzyl chloride) in the presence of a base such as potassium carbonate, often in a polar aprotic solvent like DMF or acetonitrile. Phase-transfer catalysis is another practical alternative that avoids strongly anhydrous conditions.

What solvents are suitable for dissolving 1-Benzyl-1H-indole?

1-Benzyl-1H-indole is soluble in common organic solvents including dichloromethane, chloroform, ethanol, acetone, and ethyl acetate. It has poor solubility in water due to its hydrophobic aromatic structure.

Can the benzyl group on 1-Benzyl-1H-indole be removed after synthesis?

Yes. The N-benzyl group can be cleaved by catalytic hydrogenolysis using palladium on carbon (Pd/C) under a hydrogen atmosphere, regenerating free indole (N-H indole). This makes 1-benzyl-1H-indole useful as a temporary N-protecting group strategy in multi-step synthesis.

How should 1-Benzyl-1H-indole be stored to maintain its quality?

Store 1-Benzyl-1H-indole in a tightly sealed container in a cool, dry, well-ventilated location away from light and strong oxidizing agents. Always consult the Aladdin Scientific Safety Data Sheet and Certificate of Analysis for lot-specific storage temperatures and shelf-life information.

What are the main research applications of 1-Benzyl-1H-indole?

This compound is used as a synthetic building block for indole alkaloid analogues and pharmaceutical intermediates, as a model substrate for evaluating C-H functionalization and transition-metal catalysis methodologies, and as a fragment in SAR studies targeting diverse biological targets. It also finds use in materials science as a chromophore precursor.

References

1. March, J. Advanced Organic Chemistry: Reactions, Mechanisms, and Structure, 4th ed.; Wiley-Interscience: New York, 1992. (General N-alkylation of indoles)
2. Sundberg, R. J. Indoles; Academic Press: London, 1996. (Comprehensive reference on indole chemistry and N-substituted indole synthesis)
3. Aladdin Scientific. Product Page: 1-Benzyl-1H-indole, SKU B690479. https://www.aladdinsc.com

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