≥98% for sensitive chromatographic and analytical workflows requiring minimal baseline interference.
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Storage & shipping
Store at 2-8°C Ships Wet ice Check lot-specific COA for exact specifications.
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Quality documents
SDS, COA, datasheet, and spec sheet available for download. Lot-specific COA accessible via lot number lookup.
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Literature proof
Cited in 0 peer-reviewed publications across chromatography, organic synthesis, and cross-coupling reactions.
Overview
Description
2-Ethyl-3-methoxypyrazine has been employed as internal standard for determination of taste and odour causing compounds using the granular adsorbent, Ambersorb 572, by gas chromatography-high resolution mass spectrometry.
This compound belongs to the class of organic compounds known as methoxypyrazines. These are pyrazines containing a methoxyl group attached to the pyrazine ring.
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 immunoassay or bioassay protocols apply to this small molecule. For analytical use as a standard, general guidance includes (literature-based, not item-specific):
GC/GC–MS calibration: Prepare serial dilutions (e.g., 0.1–100 µg/L) in a compatible solvent or matrix. Use PTFE-lined caps and low-adsorption vials. Include internal standards if quantitative accuracy is required.
Headspace analysis: For volatile profiling, equilibrate samples at controlled temperature; use salt-out (NaCl) to improve partitioning into headspace if matrix allows.
Storage of working solutions: Keep at 2–8 °C, protected from light in amber vials. Replace solutions regularly to mitigate adsorption or solvent loss.
Refer to your method SOPs and instrument manufacturer recommendations for exact parameters (columns, temperature ramps, ionization modes).
Biological Roles
No biological function is assigned to this catalog item beyond research use. The following points summarize general, literature-based context for methoxypyrazines; they are not medical claims.
Semiochemical/odorant: Alkylmethoxypyrazines are potent odorants found in plants (e.g., grapes, bell pepper) and can act as signaling molecules influencing herbivore behavior. Their odor detection thresholds are extremely low (ng/L–pg/L ranges in air/water), reflecting strong interactions with olfactory receptors.
Biosynthetic context: In plants and microorganisms, methoxypyrazines can arise from amino acid-derived precursors via cyclization/oxidation steps, followed by O-methylation. 2-ethyl-3-methoxypyrazine is one of the lower-mass members of this family (literature).
Metabolic fate: In biological systems, pyrazines may undergo oxidative metabolism (e.g., N-oxidation, ring hydroxylation) mediated by monooxygenases; conjugation pathways can increase polarity for excretion (species- and system-dependent; literature).
Protein interactions: As small, neutral to weakly basic heteroaromatics, methoxypyrazines can engage in π–π and hydrogen-bond interactions, pertinent to receptor binding studies in olfaction research.
Research relevance:
Serves as a well-defined probe molecule in sensory science, odorant receptor mapping, and environmental taint profiling.
Note: This product is labeled For research use only and is not intended for food, cosmetic, diagnostic, or therapeutic applications.
Buffer Applications
This compound is not a buffering reagent and is not typically used to prepare biological or analytical buffers. If using 2-ethyl-3-methoxypyrazine in aqueous experiments (e.g., partitioning or sensory thresholds), select an appropriate buffer system (e.g., phosphate, citrate, HEPES) based on your analytical method, and confirm that the buffer matrix does not adsorb or suppress the volatile/semivolatile analyte. For practical work, prioritize airtight vessels and headspace-compatible vials to limit volatilization and odor loss.
Green Alternatives
As a building block/standard, “greener” choices focus on the solvent and reagent system rather than substituting the molecule itself.
Greener solvent choices (literature-guided):
Replace chlorinated solvents (DCM) with ethyl acetate or 2-MeTHF where feasible for extractions and medium-polarity reactions.
Use CPME or 2-MeTHF in place of THF to reduce peroxide formation risk and improve life-cycle metrics.
Prefer alcohols (ethanol) over methanol when reactivity permits due to lower toxicity and renewable sourcing.
Example comparison (general):
DCM vs. EtOAc: EtOAc offers lower toxicity and better environmental profile but higher bp (77 °C) affecting removal energy.
THF vs. 2-MeTHF: 2-MeTHF is bio-based and more hydrophobic (simplifies workups), but can affect reaction selectivity and requires similar peroxide monitoring.
Hexane vs. Heptane/Isooctane: Heptane/isooctane present reduced neurotoxicity concerns and better defined boiling ranges.
Greener reagents:
Demethylation: Consider catalytic demethylation (e.g., iodide-assisted or boron-catalyzed systems) in place of stoichiometric BBr3 when compatible (still an emerging field; literature-dependent).
Oxidations: Use H2O2/urea (UHP) or Oxone in place of peracids when possible; assess compatibility with N-heteroaromatics.
Operational measures:
Minimize solvent volume via concentrated conditions or flow chemistry.
Implement carbon filtration for odor capture and VOC reduction.
Note: Evaluate EHS, waste, and LCA trade-offs for each substitution in the context of yield, selectivity, and process safety.
Pharmaceutical Uses
No pharmacopeial or excipient status is provided for this item, and it is supplied strictly for research use only.
General context (literature):
Methoxypyrazines are primarily studied as odorant standards and analytical markers rather than as pharmaceutical excipients or actives.
In drug discovery workflows, heteroaromatic fragments like pyrazines may be used as synthetic intermediates or reference compounds in physicochemical/ADME method development, but 2-ethyl-3-methoxypyrazine itself is not a typical formulation component.
Process/analytical relevance:
Potential internal/external standard for GC/GC–MS method qualification in environmental or flavor/taint investigations (matrix-dependent).
No medical or therapeutic claims are made or implied. Consult regulatory guidance before any use outside research contexts.
Physical Properties
Item-specific specifications are not provided in the Product Data. The following are general/literature characteristics for 2-ethyl-3-methoxypyrazine; they are not certificate specifications for this catalog item.
Approximate molecular weight: 138.17 g/mol (literature, computed from formula C7H10N2O)
Physical state/appearance: Not specified for this item; refer to CoA/Spec Sheet.
Boiling point: Typical reports in the literature indicate a moderate bp for C7 methoxypyrazines; approximate range 170–190 °C at 1 atm (literature; verify before process design).
Melting point: Often a low-melting solid or liquid near/below ambient temperature for small methoxypyrazines (literature; not item-specific).
Density (20–25 °C): Frequently near or slightly above 1.0 g/mL for methoxypyrazines (literature; not item-specific).
Refractive index: Not specified for this item; refer to CoA/Spec Sheet.
LogP (octanol/water): Methoxypyrazines of this size typically show logP ~1–2, reflecting modest hydrophobicity with polar functionality (literature; not item-specific).
pKa: Ring nitrogens in pyrazines are weak bases; conjugate acid pKa typically ~0–1, while phenolic/ether oxygen is not titratable under neutral conditions (literature; not item-specific).
Solubility: Generally soluble in common organic solvents (Et2O, DCM, EtOAc, alcohols) and sparingly to moderately soluble in water due to heteroatoms (literature; not item-specific).
Always consult the product’s CoA/SDS for definitive, lot-specific properties before scale-up or analytical calibration.
Quality and Grades
Grade/Purity: Not specified for this item; refer to CoA/Spec Sheet.
Guidance for interpreting possible grades (general):
Analytical/Reference standard grade: Emphasizes identity/assay and low levels of related impurities; frequently used for GC/GC–MS/LC odorant calibration. Expect accompanying purity data and, when applicable, chromatographic purity trace.
Reagent grade: Suitable for synthetic applications where trace UV absorbance or ultra-trace impurities are less critical.
Considerations specific to methoxypyrazines:
Odor purity: Trace impurities can alter odor character/potency. For sensory or analytical reference work, review GC profiles and any residual solvent/impurity disclosures on the CoA.
Stabilizers: No stabilizer is typically required for methoxypyrazines; however, absence/presence of stabilizers for this item is Not specified for this item; refer to CoA/Spec Sheet.
UV/Chromatography: If using in HPLC/GC methods, verify background UV absorbance and retention behavior; low-UV cutoffs are not applicable here, but chromatographic purity is.
Recommendation: Match grade to the application—use higher assay/trace-profiled lots for analytical standards and flexible reagent grades for synthesis. Always confirm lot-specific assay, water, and impurity limits in the CoA before critical use.
Reaction and Applications
Applications for 2-ethyl-3-methoxypyrazine span analytical odorant work and heteroaromatic synthesis.
Analytical/standards:
Frequently employed as a reference standard for method development and calibration in GC or GC–MS due to its potent odor and detectability at trace levels (literature). Its distinctive retention/ion patterns aid in profiling methoxypyrazines in food and environmental matrices.
Synthetic chemistry (general, literature):
Demethylation to 2-ethyl-3-hydroxypyrazine using Lewis acids (e.g., BBr3 or AlCl3) affords a phenoxy-type handle for subsequent etherification or esterification.
N-oxidation (e.g., mCPBA) activates the ring toward nucleophilic aromatic substitution at remaining C–H positions; subsequent Meisenheimer-type substitutions enable diversification followed by deoxygenation (e.g., PCl3, Zn/AcOH).
Directed lithiation at C-5/C-6 with strong bases (s-BuLi/TMEDA) at low temperature allows electrophile introduction (formylation, halogenation, alkylation), exploiting the directing effect of ring nitrogens.
Cross-coupling strategies typically require a halogenated precursor; thus, this compound may serve as a starting point for oxidation/activation–halogenation sequences before Suzuki/Negishi couplings.
Hydrogenation provides access to partially saturated diazines, though conditions must be tuned to avoid O-demethylation.
Practical tips:
Maintain anhydrous conditions for organolithium chemistry; quench cautiously.
For demethylation, control temperature to suppress ring cleavage; minute water content drastically affects BBr3 efficacy.
Odor control: seal reaction vessels and scrubbing off-gas (activated carbon) to mitigate persistent odor.
All conditions should be validated experimentally for the specific substrate and scale.
Reaction Conditions
The following literature-style conditions illustrate typical manipulations of 2-ethyl-3-methoxypyrazine or close analogs. They are starting points only and must be optimized experimentally.
O-Demethylation to 3-hydroxypyrazine: BBr3 (1–3 equiv per OMe) in dry DCM, −78 to 0 °C, 1–4 h, then quench with MeOH/H2O. Work up under cold conditions to suppress side reactions. Alternative: AlCl3/thiols or iodide-assisted demethylation in polar aprotic solvents.
N-Oxidation (ring activation): mCPBA (1–2 equiv) in DCM or CHCl3, 0–25 °C, 2–16 h. Monitor by TLC/LC–MS. Subsequent SNAr with amines/alkoxides typically in DMF/MeCN with base (e.g., NaH, K2CO3) at 25–80 °C.
Directed metalation/electrophile quench: s-BuLi (1.1–1.5 equiv) with TMEDA in THF at −78 °C, 0.5–1 h, then electrophile (e.g., DMF for formylation; I2/Br2 for halogenation). Warm to 0–25 °C as appropriate and quench.
Hydrogenation (caution): H2 (1–5 bar), Pd/C (5–10 wt%), EtOH/EtOAc, 25–50 °C; monitor closely to avoid over-reduction or O-demethylation.
Analytical standard preparation: Prepare stock at 100–1000 mg/L in GC-grade solvent (e.g., isooctane, methanol, or DCM). Store cold (2–8 °C) in amber, PTFE-lined vials to minimize adsorption/volatilization.
Typical yields vary widely with substitution pattern and conditions; verify on small scale first. Stringent exclusion of moisture/air is advised for organolithium and BBr3 operations. Dispose of odor-laden wastes via sealed containers and activated-carbon scrubbing where available.
Safety and Handling
Hazard classification for this specific item is not provided in the Product Data. Consult the SDS for authoritative information.
GHS/Signal word/Pictograms: Not specified for this item; refer to SDS.
Anticipated hazards (general for methoxypyrazines): May cause irritation to eyes/skin/respiratory tract; intense odor detectable at very low concentrations. Handle in a well-ventilated fume hood to avoid nuisance odor and potential sensitization.
PPE: Lab coat, safety glasses or splash goggles, and appropriate chemical-resistant gloves (e.g., nitrile). Use respiratory protection if ventilation is insufficient (per risk assessment and SDS).
Handling tips:
Avoid inhalation and skin contact; methoxypyrazines are potent odorants—prevent cross-contamination of workspaces and instruments.
Avoid strong oxidizers and strong acids/bases that could lead to ring degradation or demethylation under forcing conditions.
Spill/Exposure (general guidance):
Small spill: absorb with inert material, collect for disposal; ventilate area to disperse odor.
Skin/eye contact: rinse with water for several minutes; remove contaminated clothing; seek medical advice if irritation persists.
Inhalation: move to fresh air; obtain medical attention if symptoms occur.
Fire safety: As an organic compound, expect combustibility; use CO2, dry chemical, or foam. Combustion may produce NOx and CO.
Always defer to the SDS and institutional EHS requirements for final procedures.
Solvent Selection
This product is a heteroaromatic building block/standard, not a bulk solvent. Selection here refers to solvents for dissolving/processing 2-ethyl-3-methoxypyrazine in synthesis or analysis.
General solubility/miscibility (literature, not item-specific):
Expected to dissolve readily in common organic solvents: dichloromethane (DCM), ethyl acetate, diethyl ether, THF, acetone, methanol, ethanol, and acetonitrile.
Water solubility: limited to moderate due to polar heteroatoms balanced by hydrophobic ring/alkyl substituent.
Choosing a medium:
GC/GC–MS standards: Use high-purity solvents with low bleed (e.g., pesticide-grade hexane, isooctane, DCM, or methanol), selected based on detector compatibility and volatility.
Synthesis: Polar aprotic solvents (DCM, THF, DMF, MeCN) are suitable for electrophilic/nucleophilic substitutions or demethylation protocols. Alcohols can be used for extractions or workups but may participate in transetherification under acidic conditions.
Metalation chemistry: Use anhydrous, oxygen-free ethers (THF/Et2O) or hydrocarbons (toluene/hexane) with strong bases at low temperature.
Comparison notes:
DCM vs. EtOAc: DCM offers higher solubility and easy removal; EtOAc is a greener alternative with higher boiling point.
MeOH/EtOH vs. MeCN: Alcohols may hydrogen-bond and influence reactivity; MeCN provides polar aprotic environment useful for SNAr or salt-forming steps.
Always dry and degas solvents as required by the transformation, and confirm compatibility with planned reagents.
Storage and Reconstitution
Storage conditions (item-specific): Store at 2–8 °C.
Shipped in (item-specific): Wet ice.
Appearance: Not specified for this item; refer to CoA/Spec Sheet.
General handling:
Keep container tightly closed to prevent volatilization and pervasive odor contamination. Use secondary containment and odor-absorbing materials (e.g., activated carbon) in storage cabinets as needed.
Protect from strong oxidizers and moisture during long-term storage to maintain integrity.
Reconstitution/preparation of solutions (general):
Solvents: Dissolve in GC/HPLC-grade organic solvents such as methanol, isooctane, acetonitrile, DCM, or ethanol, selected per application.
Stock solutions: Typical analytical stocks 0.1–1.0% w/v (1–10 mg/mL). For trace-level work, prepare fresh dilutions in low-adsorption vials with PTFE-lined caps.
Stability: Working solutions are best stored refrigerated (2–8 °C) and used promptly. For longer storage, prepare aliquots to avoid repeated opening and potential solvent evaporation/adsorption losses.
Freeze–thaw: Not generally required; avoid freezing aqueous mixtures that may promote phase separation or volatility losses on thawing.
Always consult the CoA/SDS for lot-specific guidance and observe institutional chemical hygiene protocols. Product is supplied For research use only.
Structure and Identity
A heteroaromatic methoxypyrazine bearing an ethyl substituent, commonly used as a reference odorant and as a heteroaromatic building block.
SKU: E474282
Product name: 2-Ethyl-3-methoxypyrazine
CAS: 25680-58-4 (item-specific)
CID: 33135 (item-specific)
InChIKey: 69197 (item-specific; truncated format as provided)
SMILES: Not specified for this item; refer to CoA/Spec Sheet.
Molecular formula: C7H10N2O (literature)
Molecular weight: ~138.17 g/mol (literature)
Structural features (general description):
Core ring: 1,4-diazine (pyrazine) — a six‑membered aromatic ring with nitrogens at positions 1 and 4.
Substituents: ethyl group at C-2 and methoxy (–OCH3) at C-3 (adjacent carbons on the ring).
Functional groups: aromatic N-heteroaromatic ring (electron-deficient), aryl ether (methoxy), and an alkyl side chain (ethyl).
Stereochemistry: achiral; no stereogenic centers.
2D arrangement in words: starting at a ring nitrogen (position 1) and proceeding clockwise, the ring atoms are N(1)–C(2)[bearing –CH2CH3]–C(3)[bearing –OCH3]–N(4)–C(5)(H)–C(6)(H), with conjugation across the ring and lone pairs on N(1) and N(4) contributing to aromaticity.
Note: Identity parameters not explicitly provided above (e.g., SMILES) should be confirmed against the product CoA/Spec Sheet for this specific lot.
Synthetic Utility
2-Ethyl-3-methoxypyrazine provides a compact, electron-deficient N-heteroaromatic scaffold with orthogonal handles (aryl ether, alkyl substituent) that enable several diversification tactics (literature, general guidance):
O-Functional handle: Demethylation to the phenol (3-hydroxypyrazine) enables subsequent O-alkylation, O-acylation, or formation of carbonate/urethane derivatives.
Ring activation via N-oxide: Oxidation to the pyrazine N-oxide(s) increases susceptibility toward nucleophilic aromatic substitution at C-5/C-6, allowing introduction of amines, thiols, or alkoxides, followed by deoxygenation to regenerate the aromatic core.
Directed metalation: Strong base-mediated lithiation (e.g., s-BuLi/TMEDA) at C-5/C-6 affords access to electrophile trapping (formylation, halogenation, sulfenylation), expanding substitution patterns inaccessible by direct electrophilic aromatic substitution.
Cross-coupling routes: Although the parent is not halogenated, sequential activation (e.g., halogenation after lithiation) enables Suzuki, Negishi, or Buchwald–Hartwig couplings on a preinstalled aryl halide.
Redox tailoring: Partial hydrogenation or hydride addition (with control) can furnish dihydropyrazines or open routes to saturated diamines after further transformations.
Advantages:
High chemoselectivity opportunities based on differential reactivity at OMe, ring nitrogens, and specific carbons.
Compact size and strong odor facilitate tracking in reaction monitoring (GC/GC–MS) at very low levels.
Caveats: Odor management is essential; demethylation and strong base steps require rigorous anhydrous technique.
Target Specificity
Not applicable. This product is a small-molecule reagent/standard, not a biological affinity reagent. No antigen/epitope, clone, isotype, or species reactivity information applies.
Frequently Asked Questions
What is the purity of this product?
This product is supplied at ≥98% purity (chemical assay). Lot-specific values are stated on the Certificate of Analysis.
How should this product be stored?
Store at 2–8 °C. Refrigerated storage is required to maintain the specified shelf life.
How is this product shipped?
This product ships chilled on wet ice. Unpack on arrival and transfer it to the storage condition stated above.
What are the CAS number, molecular formula and molecular weight?
The CAS Number is 25680-58-4, the molecular formula is C7H10N2O, and the molecular weight is 138.17 g/mol. InChIKey DPCILIMHENXHQX-UHFFFAOYSA-N.
What documentation is provided?
Available product documentation, including Certificates of Analysis (COA), Safety Data Sheets (SDS), and specification sheets, is shown in the product document area. Document availability and access follow the current site policy.
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