This compound belongs to the class of organic compounds known as carboxylic acid esters. These are carboxylic acid derivatives in which the carbon atom from the carbonyl group is attached to an alkyl or an aryl moiety through an oxygen atom (forming an ester group).
External Descriptors
Not available
1. Djoumbou Feunang Y, Eisner R, Knox C, Chepelev L, Hastings J, Owen G, Fahy E, Steinbeck C, Subramanian S, Bolton E, Greiner R, and Wishart DS. ClassyFire: Automated Chemical Classification With A Comprehensive, Computable Taxonomy. Journal of Cheminformatics, 2016, 8:61.
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Application Protocols
No standardized biological assay protocols apply to this small-molecule intermediate.
Synthetic use protocol sketch (general guidance only; not product specifications):
Representative enolate alkylation:
Dry glassware; charge with Ethyl 2-oxocyclopentylacetate in anhydrous THF under argon.
Cool to −78 °C; add 1.1 equiv LDA dropwise (preformed from n-BuLi/diisopropylamine) and stir 30–60 min.
Add electrophile (1.2–1.5 equiv) at −78 to −40 °C; stir until consumption by TLC/GC.
Quench with sat. NH4Cl at low temperature; extract, dry, and purify by chromatography.
For project-specific methods, consult the literature and adapt conditions to the substrate and scale.
Biological Roles
This product is a synthetic organic intermediate rather than a biomolecule. It does not have recognized intrinsic biological roles or functions.
General context (literature):
β-Keto esters are occasionally used as prochiral precursors in biocatalytic transformations (e.g., ketoreductases, esterases), but Ethyl 2-oxocyclopentylacetate itself is not a metabolite or signaling molecule.
In chemical biology or medicinal chemistry workflows, it may serve as a scaffold to construct substituted cyclopentanone motifs that appear in natural products or small-molecule probes.
Use strictly for research and laboratory synthesis. No clinical or therapeutic applications are implied.
Buffer Applications
Not typically applicable. Ethyl 2-oxocyclopentylacetate is a nonionic organic intermediate and is not used to prepare aqueous buffer systems. For practical use information, see Reaction & Applications, Synthetic Utility, and Reaction Conditions.
Green Alternatives
Greener considerations focus on the choice of reaction media and bases used with Ethyl 2-oxocyclopentylacetate; the substrate itself is a typical organic intermediate.
Solvent alternatives (general literature guidance):
Replace THF/Et2O with 2-MeTHF or CPME for enolate chemistry; both offer higher boiling points, better hydrophobicity, and improved safety profiles.
Use MeCN or propylene carbonate for SN2 alkylations with inorganic bases under phase-transfer or biphasic conditions.
Favor EtOAc or MeTHF over chlorinated solvents for neutral steps and extractions when feasible.
Bases and reagents:
Where strong bases (LDA, LiHMDS) are not essential, consider K2CO3 or Cs2CO3 with catalytic phase-transfer agents to reduce hazard and waste.
Employ catalytic organobases (DBU, TBD) for Michael additions when compatible with selectivity.
Small comparison (general):
THF vs 2-MeTHF: Similar performance in enolate generation; 2-MeTHF derives from renewable feedstocks, offers easier phase separation, and lower peroxide formation tendency.
DCM vs EtOAc: EtOAc is biodegradable and less toxic; however, DCM may offer superior solubility for some highly lipophilic substrates.
Waste minimization:
Implement telescoped sequences (e.g., enolate alkylation → cyclization without isolating intermediates) and solvent recycling. Use in-line drying to extend solvent life.
Select greener choices based on LCA, process safety, and performance trade-offs validated at lab scale.
Pharmaceutical Uses
Formulation/excipient role: Not applicable; this compound is not used as a standard pharmaceutical excipient.
Process chemistry relevance (general/literature):
Serves as a building block for assembling substituted cyclopentanone/cyclopentanol motifs frequently encountered in agrochemical and medicinal chemistry candidates.
The β-keto ester handle allows convergent routes via enolate alkylation, Michael addition, and subsequent decarboxylation to reach bicyclic cores.
Can be leveraged in chiral synthesis by enantioselective alkylations or enzymatic resolutions to introduce stereochemistry on the side chain.
Regulatory status:
No compendial monograph is indicated (e.g., USP/EP) for this specific intermediate. If used in GMP settings, establish appropriate specifications, impurity limits, and residual solvent controls per ICH Q7/Q3 guidelines.
All mentions pertain to research and process development contexts only; no therapeutic claims are made.
Physical Properties
Item-specific specifications (this lot):
Appearance: Not specified for this item; refer to CoA/Spec Sheet.
Molecular Formula: Not specified for this item; refer to CoA/Spec Sheet.
Molecular Weight: Not specified for this item; refer to CoA/Spec Sheet.
Literature/general values and behavior (for reference only; not product specifications):
Physical state: typically a colorless to pale yellow liquid/oil for related ethyl 2-oxocycloalkylacetates.
Acidity/tautomerism: exhibits keto–enol tautomerization; enol content increases in nonpolar and hydrogen-bond-accepting solvents.
Solubility: expected to be miscible with common organic solvents (EtOAc, DCM, THF, acetone) and of low solubility in water, consistent with β-keto esters.
Volatility: moderate; handle in a well-ventilated hood.
Notes for use:
The activated methylene has an estimated pKa in the 10–13 range for analogous β-keto esters (literature), enabling deprotonation with alkoxides, carbonates, or stronger bases (e.g., LDA) depending on selectivity needs.
Refractive index, density, BP/MP, UV cutoff: Not specified for this item; refer to CoA/Spec Sheet.
Always consult the Certificate of Analysis for lot-specific physical data before scale-up.
Quality and Grades
Item-specific grade/purity: Not specified for this item; refer to CoA/Spec Sheet.
Guidance on quality considerations (general):
For enolate chemistry and stereoselective alkylations, trace water and acids/bases can affect outcomes. Where possible, use freshly opened material or verify purity by GC/HP-NMR prior to critical steps.
Chromatography-grade or low-UV grade can be desirable if the material is to be used as a reference standard in analytical methods; absent a specified HPLC/GC grade, validate for intended analytical application.
Stabilizers: None indicated in the Product Data. If an inhibitor or acid stabilizer is present in other suppliers’ materials, it can influence enolate formation and side reactions; remove or account for it during process development.
Documentation: For assay, impurity profile, residual solvents, and water content, consult the CoA/Spec Sheet for the specific lot supplied by Aladdin Scientific.
Practical QC tips:
Assess by 1H/13C NMR (look for characteristic β-keto ester methylene ~3–4 ppm and carbonyl carbons ~170–210 ppm, literature).
Check for transesterification or self-aldol impurities on storage; a quick GC or LC-MS scan is advisable before scale-up.
Reaction and Applications
Ethyl 2-oxocyclopentylacetate is a versatile cyclic β-keto ester widely used as a building block in heterocycle and carbocycle synthesis.
Typical applications (literature/general):
Enolate alkylation: The activated methylene undergoes regioselective C-alkylation with primary alkyl halides or Michael acceptors. Bases: LDA, LiHMDS, NaH, K2CO3 (phase-transfer), or alkoxides depending on selectivity.
Michael additions: Soft nucleophile character enables conjugate additions to acrylates, enones, maleimides; subsequent cyclizations can furnish spiro- or annulated systems.
Aldol/Claisen/Dieckmann variants: Intramolecular condensations can elaborate the cyclopentane ring; intermolecular aldols provide β-hydroxy esters for further manipulation.
Robinson annulation: The β-keto ester moiety participates in classical Robinson annulations to assemble bicyclic enones.
Decarboxylative routes: Hydrolysis to the acid followed by thermal decarboxylation delivers substituted cyclopentanones (useful for terpene or prostaglandin fragments, literature).
Chemoselective reductions: Ester reduction to alcohols (DIBAL-H) while retaining the ring ketone, or vice versa (ketone protection/reduction strategies), affords orthogonally functionalized intermediates.
Practical tips:
Control O- vs C-alkylation: favor C-alkylation with strong, non-nucleophilic bases at low temperature in coordinating ethers; O-alkylation increases with higher temperature or hard electrophiles.
Protecting strategies: As needed, protect the ring ketone (as ketal) to direct reactivity to the β-keto ester site.
Workup: Quench enolates at low temperature with electrophile present, then buffered aqueous quench to minimize retro- or over-alkylation.
Reaction Conditions
General conditions (literature guidance; verify for your substrate and scale):
Enolate generation:
Strong base: LDA or LiHMDS (1.05–1.2 equiv) in dry THF or 2-MeTHF at −78 to −20 °C, 0.5–2 h. Add electrophile at low temperature, then warm as needed.
Mild base: K2CO3 or Cs2CO3 (2–3 equiv) in MeCN or acetone at rt to 60 °C for SN2 alkylations with primary halides; phase-transfer (e.g., TBAB) can accelerate.
Michael additions: DBU (10–30 mol%) or secondary amines as catalysts in MeCN/EtOAc at rt to 50 °C; or stoichiometric NaOMe/MeOH when transesterification is acceptable.
Ketone protection: Ethylene glycol, p-TsOH, Dean–Stark in toluene or catalytic acid in acetone with molecular sieves, 1–4 h, to form cyclic ketals.
Reductions:
Ester to aldehyde: DIBAL-H (1.2–1.5 equiv) in toluene/CH2Cl2 at −78 to −40 °C; quench with Rochelle’s salt.
Ketone-selective reduction: NaBH4 in MeOH/EtOH at 0–25 °C (if ester stability is acceptable) to furnish cyclopentanol esters.
Hydrolysis/decarboxylation: saponify with NaOH/EtOH–H2O, then acidify; decarboxylate β-keto acid by heating (e.g., 120–180 °C) or via aqueous reflux, depending on substitution pattern.
Yields will vary with electrophile and conditions; run small-scale scouting to optimize base, solvent, and temperature. Maintain anhydrous, oxygen-limited conditions to suppress side reactions and oligomerization.
Safety and Handling
Item-specific hazard information:
Signal Word: Not specified for this item; refer to SDS.
H-Statements: Not specified for this item; refer to SDS.
GHS Classification: Not specified for this item; refer to SDS.
Pictograms: Not specified for this item; refer to SDS.
General laboratory safety guidance (literature/ best practice):
Likely harmful if swallowed and irritating to eyes/skin like many esters and ketones; avoid inhalation of vapors and contact. Use in a fume hood.
Personal protective equipment: lab coat, safety glasses or goggles, and suitable chemical-resistant gloves (e.g., nitrile). Consider splash protection for scale-up.
Handling: Minimize exposure to air/moisture to reduce self-condensation or oxidation; the product is supplied argon-charged. Keep containers tightly closed.
Incompatibilities: Strong bases/acids (uncontrolled transesterification/condensation), strong oxidizers. Avoid prolonged contact with reactive metals when using strong bases.
First aid (overview; defer to SDS):
Inhalation: move to fresh air; seek medical attention if symptoms persist.
Skin/eye contact: rinse with water for several minutes; remove contaminated clothing; get medical advice if irritation continues.
Ingestion: rinse mouth; do not induce vomiting; seek medical attention.
Fire safety: Treat as combustible organic. Use CO2, dry chemical, or foam. Thermal decomposition may release irritating vapors.
Always consult the official SDS for authoritative safety and regulatory information.
Solvent Selection
Applicability: This compound is an organic intermediate, not a solvent. The guidance below focuses on choosing media for reactions using Ethyl 2-oxocyclopentylacetate.
General solvent compatibility (literature/general):
Polar aprotic solvents (THF, DME, MTBE, 2-MeTHF, DMF, DMSO, acetonitrile) support enolate generation and SN2 alkylations.
Moderately polar esters (EtOAc), chlorinated solvents (DCM, CHCl3), and hydrocarbons (toluene, heptane) are suitable for neutral transformations, acylations, and condensations.
Aqueous miscibility: low; biphasic systems with carbonate bases (e.g., K2CO3/MeCN/H2O) can be used for mild alkylations or Michael additions.
Selection tips:
Strong base enolizations (LDA, LiHMDS): use dry ethereal solvents (THF, 2-MeTHF) at −78 to 0 °C to control regioselectivity.
O- vs C-alkylation control: less polar, less coordinating solvents (toluene, MTBE) and cation choice (K+ vs Li+) influence selectivity (literature).
For transesterification minimization, avoid protic alcohol solvents unless desired; use neutral aprotic media.
Comparison (general):
THF: excellent for enolate chemistry; peroxide risk and low flash point demand precautions.
2-MeTHF: greener alternative; similar performance with improved safety and water tolerance.
Acetonitrile: good for phase-transfer or carbonate-base alkylations; higher boiling and easy workup.
Always dry solvents and degas as needed; moisture can quench enolates and broaden impurity profiles.
Storage and Reconstitution
Item-specific storage and shipping (from Product Data):
Storage Conditions: Store at 2–8 °C, Argon charged.
Shipped In: Wet ice.
Best practices (general):
Keep container tightly closed under inert gas (argon or nitrogen) to minimize oxidation or base-catalyzed self-condensation.
Protect from moisture and prolonged exposure to air. Use septum-sealed bottles for repeated withdrawals; backfill with inert gas after use.
If solidification or crystallization occurs at low temperature, allow to warm to room temperature under inert atmosphere and homogenize before use.
Do not freeze–thaw repeatedly if the material forms a glass or semi-solid; instead, aliquot under inert gas upon first opening for long-term work.
Reconstitution: Not applicable; supplied as a neat reagent. If dilution is desired to make a stock solution, prepare under inert atmosphere in a dry, compatible solvent (e.g., THF, EtOAc, toluene) and store cold under argon. Validate solution stability by analytical testing prior to extended storage.
Research Use Note: For research use only.
Structure and Identity
Ethyl 2-oxocyclopentylacetate is a cyclic β-keto ester featuring a cyclopentanone ring bearing a methylene–acetate ethyl ester side chain. The molecule contains two carbonyl groups (a ketone within the five-membered ring and an ester) separated by a methylene, enabling enolization and classic β-dicarbonyl chemistry.
Item-specific (from Product Data):
CAS: 20826-94-2
InChIKey: 279081 (as provided)
SMILES: Not specified for this item; refer to CoA/Spec Sheet.
Molecular Formula: Not specified for this item; refer to CoA/Spec Sheet.
Molecular Weight: Not specified for this item; refer to CoA/Spec Sheet.
2D description: a five-membered carbocycle with one carbonyl at C-2 (cyclopentanone). At the α-position relative to the ring ketone, a –CH2–CO2Et substituent extends outward, giving a –CO–CH2–CO2Et conjugation pathway when enolized.
Stereochemistry: no stereocenters in the parent scaffold; tautomerism between keto and enol forms is expected (literature).
Synthetic Utility
Key reactivity derives from the β-dicarbonyl system embedded in a cyclopentanone framework:
Enolate chemistry: The methylene between the ring ketone and the ester is strongly activated. Lithiation (LDA/LiHMDS) affords a resonance-stabilized enolate that reacts with alkyl halides, epoxides, and Michael acceptors. Cation and solvent control influence regiochemistry and O- versus C-alkylation.
Annulation strategies: Participation in Robinson annulation and Michael–aldol sequences provides bicyclic enones and decalin-like architectures, enabling rapid molecular complexity growth from a compact scaffold.
Selective functional group manipulation: Orthogonal reduction or protection of the ring ketone (e.g., ketalization) enables targeted transformations at the ester or vice versa (DIBAL-H to aldehyde, LiAlH4 to diol after protection).
Decarboxylative elaboration: Hydrolysis to the β-keto acid followed by decarboxylation yields substituted cyclopentanones. Subsequent α-functionalization, Baeyer–Villiger oxidation, or Wittig/Julia olefination installs further diversity.
Cross-coupling handles: After α-halogenation, the product can be converted to vinyl/allyl derivatives that engage in Pd-catalyzed couplings (via enol triflates or vinyl halides) to extend the ring system.
Retrosynthetic value:
Ethyl 2-oxocyclopentylacetate enables disconnections that place substituents α to a cyclopentanone while maintaining a removable ester, offering traceless activation after decarboxylation.
Target Specificity
Not applicable. This product is a small-molecule synthetic intermediate and is not an antibody, enzyme, or affinity reagent. No target specificity, epitope, or isotype information applies.
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