Chemical Identity and Structure

1-Ethyl-4-Piperidinecarboxylic Acid Ethyl Ester is a saturated, six-membered nitrogen heterocycle belonging to the piperidine family. Its structure consists of a piperidine ring bearing an N-ethyl substituent at position 1 and an ethyl ester group at the 4-position (carboethoxy group). This bifunctional architecture combines the basicity of a tertiary aliphatic amine with the electrophilicity and synthetic versatility of an ester, making it a valuable scaffold in structure–activity relationship (SAR) studies.

The compound is closely related to ethyl isonipecotate (ethyl piperidine-4-carboxylate), differing by the presence of the N-ethyl group that increases lipophilicity and modifies the pKa of the nitrogen center relative to the secondary amine parent. These electronic and steric differences are frequently exploited when designing CNS-active agents or enzyme inhibitors that require a defined substitution pattern on the piperidine nitrogen.

Synthetic Applications and Role as a Building Block

As a bifunctional synthon, 1-Ethyl-4-Piperidinecarboxylic Acid Ethyl Ester offers two principal handles for further elaboration: the ester group and the nitrogen-containing ring. The ester moiety can be hydrolyzed to the corresponding carboxylic acid, reduced to the alcohol, converted to amides via aminolysis, or engaged in Claisen-type condensations. Meanwhile, the N-ethyl piperidine ring provides a conformationally rigid, well-defined three-dimensional framework.

Common synthetic transformations include:

• Amide coupling: Saponification of the ester followed by coupling with amines yields piperidine-4-carboxamides, which are prevalent scaffolds in CNS drug discovery.
• Reduction: Treatment with LiAlH₄ or DIBAL-H affords the corresponding piperidine-4-methanol derivative useful for further functionalization.
• Knoevenagel and Dieckmann condensations: The active methylene alpha to the ester enables condensation reactions to build more complex ring systems.
• N-Quaternization: Although the nitrogen is already tertiary, it can be quaternized for the synthesis of ionic compounds or prodrugs.

These versatile transformations position this compound as an efficient precursor for libraries of piperidine-containing drug candidates.

Relevance in Medicinal Chemistry and Drug Discovery

The piperidine ring is among the most frequently occurring heterocycles in approved pharmaceuticals, owing to its favorable pharmacokinetic profile, metabolic stability, and ability to mimic natural amino acid geometry. The 4-carboxylate substitution pattern is particularly valuable because the ester or derived amide projects a hydrogen-bond acceptor or donor into a well-defined vector relative to the ring, facilitating target engagement.

1-Ethyl-4-Piperidinecarboxylic Acid Ethyl Ester is used in the preparation of analgesics, antihistamines, antipsychotics, and other bioactive compound classes that incorporate the 4-substituted piperidine motif. Researchers working on GPCR ligands, ion-channel modulators, and enzyme inhibitors frequently employ this scaffold as a starting material or key intermediate. Its N-ethyl group provides a moderate lipophilicity boost compared with N-methyl or unsubstituted variants, which can be advantageous for CNS penetration studies.

Handling, Storage, and Safety Considerations

As with most tertiary amine-containing organic compounds, 1-Ethyl-4-Piperidinecarboxylic Acid Ethyl Ester should be handled in a well-ventilated fume hood with appropriate personal protective equipment (PPE), including nitrile gloves, safety goggles, and a laboratory coat. Avoid inhalation of vapors and contact with skin or eyes.

The compound should be stored in a tightly sealed container, away from moisture, heat, and strong oxidizing agents. Refrigerated storage (2–8 °C) or storage at room temperature under inert atmosphere is generally recommended to maintain compound integrity over time. Users should consult the Safety Data Sheet (SDS) provided by Aladdin Scientific for complete hazard information, GHS classifications, and first-aid measures specific to this reagent (SKU: E725556) before use.

Waste disposal must comply with local institutional and governmental regulations governing nitrogen-containing organic solvents and reagents.

Ordering Information and Product Specifications

1-Ethyl-4-Piperidinecarboxylic Acid Ethyl Ester is available from Aladdin Scientific under SKU E725556. Researchers and procurement teams are encouraged to contact Aladdin Scientific directly or visit the product page for current pricing, available quantities, purity specifications, certificate of analysis (CoA), and SDS documentation.

For bulk inquiries, custom synthesis requirements, or questions regarding regulatory documentation, please reach out to the Aladdin Scientific technical support and sales team. Aladdin Scientific is committed to providing high-quality research reagents with rigorous quality-control documentation to support reproducible science.