7-Benzyloxyindole-3-carboxaldehyde: Properties & Lab Uses

7-Benzyloxyindole-3-carboxaldehyde is a protected indole-based aldehyde building block widely employed in medicinal chemistry and heterocyclic synthesis as a versatile intermediate for constructing bioactive indole scaffolds.

Chemical Name

7-Benzyloxyindole-3-carboxaldehyde

Core Scaffold

Indole ring with benzyloxy group at C-7 and aldehyde at C-3

Primary Use

Synthetic building block and intermediate in medicinal and heterocyclic chemistry

Aladdin SKU

B770535

Functional Groups

Aldehyde (CHO) and benzyl ether (OBn) on an indole nucleus

Protection Strategy

Benzyloxy group serves as a removable protecting group for the C-7 hydroxyl

Chemical Structure and Key Properties

7-Benzyloxyindole-3-carboxaldehyde belongs to the indole family of heterocyclic compounds, featuring a bicyclic system composed of a benzene ring fused to a pyrrole ring. Two key functional groups define its reactivity: an aldehyde (–CHO) at the C-3 position and a benzyloxy (–OBn) substituent at the C-7 position on the benzo ring.

The C-3 aldehyde is a highly reactive electrophilic handle that participates in condensation reactions, reductive aminations, Wittig olefinations, and Knoevenagel condensations, making this compound a versatile electrophilic partner in multi-step synthesis. The C-7 benzyloxy group functions as a protecting group for an underlying phenolic hydroxyl, enabling selective chemistry to be performed on the molecule before deprotection under mild hydrogenolysis conditions.

As a solid aromatic aldehyde, this compound is expected to be moisture-sensitive to a moderate degree and should be stored in a cool, dry environment away from light to prevent oxidation of the aldehyde functionality. Specific melting point, solubility, and purity data should be confirmed against the certificate of analysis supplied with each lot.

Synthesis Applications and Research Relevance

The indole scaffold is among the most prevalent heterocyclic motifs in natural products and pharmaceutical agents. 7-Hydroxyindole derivatives in particular appear in biologically active molecules, and the 7-benzyloxyindole platform provides a practical entry point to this chemical space while keeping the C-7 oxygen masked during synthetic elaboration.

The C-3 aldehyde of 7-Benzyloxyindole-3-carboxaldehyde serves as a handle for numerous transformations commonly applied in medicinal chemistry libraries. Reductive amination with primary or secondary amines yields aminomethyl indoles; condensation with active methylene compounds via Knoevenagel protocols generates extended conjugated systems; and Wittig or Horner–Wadsworth–Emmons reactions produce vinyl indoles useful as pharmacophores or fluorescent probes.

After completion of the desired transformations, the benzyl protecting group can be cleanly removed by catalytic hydrogenolysis (e.g., Pd/C under H₂ atmosphere) to unmask the free 7-hydroxyindole, enabling further functionalization or biological evaluation of the target molecule. This orthogonal protection strategy makes the compound especially valuable in multi-step total synthesis and combinatorial library preparation.

Handling, Storage, and Safety Considerations

As with most aromatic aldehydes and heterocyclic intermediates, 7-Benzyloxyindole-3-carboxaldehyde should be handled with standard laboratory precautions. Personnel should use appropriate personal protective equipment including nitrile gloves, safety glasses, and a laboratory coat. Operations that generate dust or aerosols should be performed in a well-ventilated fume hood.

The compound should be stored in a tightly sealed container under inert atmosphere where possible, kept away from strong oxidizing agents, strong bases, and sources of heat or ignition. Refrigerated storage (2–8 °C) in the dark is typically recommended for aldehyde-containing reagents to extend shelf life and prevent decomposition.

Users should consult the Safety Data Sheet (SDS) specific to this product (Aladdin SKU B770535) before use. All waste disposal must comply with local environmental regulations for organic chemical waste. Specific GHS hazard classifications and precautionary statements should be verified from the current product SDS.

Ordering and Quality Information

7-Benzyloxyindole-3-carboxaldehyde is available from Aladdin Scientific under SKU B770535. Researchers should request a current Certificate of Analysis (CoA) at the time of purchase to confirm lot-specific purity, identity (e.g., NMR, HPLC, or MS data), and physical characteristics.

For bulk quantities, custom packaging, or specific purity grades required for GMP-adjacent workflows, contact Aladdin Scientific's technical sales team. Volume pricing and availability may vary; procurement teams are encouraged to reach out for institutional or contract pricing arrangements.

This reagent is intended for research use only and is not suitable for diagnostic, therapeutic, or food-related applications without further evaluation and regulatory approval.

Frequently asked questions

What reactions can the C-3 aldehyde of 7-Benzyloxyindole-3-carboxaldehyde participate in?

The C-3 aldehyde is a reactive electrophilic site suitable for reductive amination, Knoevenagel condensation, Wittig or Horner–Wadsworth–Emmons olefination, and nucleophilic addition reactions. These transformations make it a highly versatile building block for constructing complex indole-containing molecules in medicinal chemistry and natural product synthesis.

How is the benzyloxy protecting group removed from 7-Benzyloxyindole-3-carboxaldehyde?

The benzyloxy (OBn) group is typically removed by catalytic hydrogenolysis, most commonly using palladium on carbon (Pd/C) as catalyst under a hydrogen atmosphere in a suitable solvent such as ethanol or ethyl acetate. This mild and selective deprotection reveals the free 7-hydroxyindole without disturbing other sensitive functional groups in most contexts.

What are the recommended storage conditions for 7-Benzyloxyindole-3-carboxaldehyde?

This compound should be stored in a tightly sealed container in a cool (2–8 °C), dry, and dark environment to prevent oxidation of the aldehyde group and degradation over time. An inert atmosphere is advisable where feasible. Always consult the product's Safety Data Sheet and Certificate of Analysis for lot-specific storage recommendations.

Is 7-Benzyloxyindole-3-carboxaldehyde suitable for pharmaceutical or diagnostic use?

No. This reagent is supplied for research use only. It is not intended or approved for use in pharmaceutical manufacturing, diagnostic testing, therapeutic applications, or food-related processes without independent evaluation and the necessary regulatory approvals.

References

1. Joule, J. A.; Mills, K. Heterocyclic Chemistry, 5th ed.; Wiley-Blackwell: Oxford, 2010. (General reference for indole chemistry and reactivity.)
2. March, J. Advanced Organic Chemistry: Reactions, Mechanisms, and Structure, 4th ed.; Wiley: New York, 1992. (Reference for aldehyde reactivity including reductive amination and Wittig reactions.)
3. Clayden, J.; Greeves, N.; Warren, S. Organic Chemistry, 2nd ed.; Oxford University Press: Oxford, 2012. (Textbook reference for benzyl ether protecting group strategies and hydrogenolysis.)

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