2,3,5,6-Tetramethylpyrazine (CAS 1124-11-4) — Sweet Heart to base Note Fragrance Ingredient
2,3,5,6-Tetramethylpyrazine
CAS 1124-11-4
What Is 2,3,5,6-Tetramethylpyrazine?
2,3,5,6-Tetramethylpyrazine is a synthetic aroma compound found in roasted nuts, coffee, and some tobacco products. It adds a warm, nutty character to fragrances and flavors. This molecule matters because it mimics natural roasting processes, creating comforting gourmand accords without actual food ingredients. It’s commonly used in both fine fragrances and functional products like candles.
Safety Profile
GENERALLY SAFEWhat Does 2,3,5,6-Tetramethylpyrazine Smell Like?
A rich, roasted nut core with hints of dark chocolate and coffee grounds. Opens with a slightly burnt caramel top note that evolves into a deep, earthy heart reminiscent of roasted hazelnuts. The dry-down reveals a subtle woody-smoky character that lingers close to the skin. Compared to simpler pyrazines, the tetramethyl structure adds complexity – imagine the difference between milk chocolate and 85% dark single-origin.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used at trace levels to enhance the almond-vanilla accord, adding roasted depth without overt gourmand sweetness.
Contributes to the dark chocolate facet of the truffle accord, blending with patchouli and ylang.
2D Molecular Structure
SMILES: CC1=NC(C)=C(C)N=C1C
Chemistry, Properties & Perfumer Guide
The Chemistry
An alkylpyrazine with four methyl groups creating steric hindrance that slows evaporation. Synthesized via condensation reactions of diacetyl with ammonia derivatives. The symmetrical substitution pattern makes this one of the more stable pyrazines, resisting oxidation better than trimethyl variants. While not chiral itself, it frequently occurs in racemic mixtures with other pyrazines in natural extracts.
Physical & Chemical Properties
| Boiling Point | 242-244 °C |
|---|---|
| Vapor Pressure | 0.01 mmHg at 25°C |
| LogP | 2.34 |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.1-0.5% | Up to 1% | Used sparingly for depth |
| Functional Fragrances | 0.05-0.2% | Up to 0.5% | Adds warmth to air fresheners |
Classic Accords
Tip: Use below 0.5% to avoid dominating compositions with its roasted character.
Alternatives & Comparisons
More volatile with sharper roasted peanut character, suitable when lighter top notes are needed.
Provides popcorn-like notes at ultra-low levels, useful for savory tweaks.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted by IFRA. Listed on 2019 amendment as under review for potential sensitization.
GHS Classification
RIFM Assessment
RIFM evaluation ongoing as of 2023 due to structural alerts for potential sensitization.
Sustainability
Synthetic production avoids agricultural impacts of natural pyrazine sources. Most commercial routes use petrochemical precursors, though some manufacturers are exploring bio-based routes via fermentation. Energy-intensive purification required due to similar boiling points of pyrazine isomers.
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References
- PubChem Compound Summary for CID 14260 PubChem
- Flavor and Extract Manufacturers Association (2020). Safety assessment.
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 1124-11-4Physical Properties
| Molecular Weight | 136.19 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 1.3🔬 PubChem |
| Boiling Point | 190 °C🔬 EPA CompTox |
| Flash Point | 71.6 °C🔬 EPA CompTox |
| log Kp (skin permeability) | -2.608💻 Calculated |
| SMILES | CC1=C(N=C(C(=N1)C)C)C🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
Odor & Flavor
| Primary Descriptors | chocolatenutty• leffingwell |
| Functional Groups | aromatic💻 RDKit |
Sensory Thresholds
| Odor Detection Threshold | 3.3138 ppm (n=6)📖 van Gemert |
Regulatory Status
| IOFI Classification | Nature Identical📖 Fenaroli |
Physical data: PubChem (NIH/NLM), U.S. EPA CompTox Dashboard, EPA OPERA models, RDKit. Odor & flavor: Arctander (Perfume & Flavor Chemicals), Fenaroli's Handbook of Flavor Ingredients, Leffingwell. Thresholds: van Gemert (Compilations of Odour Threshold Values). Regulatory: IFRA Standards 51st, FEMA GRAS. Trade names: Surburg (Common Fragrance & Flavor Materials). All data compiled and cross-referenced for perfumertools.com.
Physicochemical Properties
DTXSID: DTXSID6047070
Physical Properties
| Molecular Weight | 136.198 g/mol🔬 EPA CompTox |
| Density | 1.08 g/cm^3🔬 EPA CTX |
| Boiling Point | 190 °C🔬 EPA CTX |
| Melting Point | 84.944 °C🔬 EPA CTX |
| Flash Point | 71.675 °C🔬 EPA CTX |
| Refractive Index | 1.504 Dimensionless📊 OPERA |
| Molar Volume | 140.982 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 1.28 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 1.425 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 1.426 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.74 Log10 unitless📊 OPERA |
| Water Solubility | 0.451 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.689 mmHg📊 OPERA |
| Viscosity | 2.044 cP📊 OPERA |
| Surface Tension | 34.648 dyn/cm📊 OPERA |
| Thermal Conductivity | 123.067 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 25.78 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 2 count💻 Computed |
| Rotatable Bonds | 0 count💻 Computed |
| Aromatic Rings | 1 count💻 Computed |
| Molar Refractivity | 41.735 cm^3/mol📊 OPERA |
| Polarizability | 16.545 Å^3📊 OPERA |
Data Sources:
🔬 EPA Experimental data from U.S. EPA CompTox Chemicals Dashboard & CTX APIs. 📊 OPERA Predicted using EPA's OPERA QSAR models. 💻 Computed Calculated from SMILES using RDKit.
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