2,5-Dimethylpyrazine (CAS 123-32-0) — Sweet Heart Note Fragrance Ingredient
2,5-Dimethylpyrazine
CAS 123-32-0
What Is 2,5-Dimethylpyrazine?
2,5-Dimethylpyrazine is a synthetic aroma compound that adds roasted, nutty notes to fragrances. Commonly encountered in coffee, chocolate, and tobacco scents, it provides depth and warmth. This ingredient matters because it authentically recreates gourmand nuances at trace concentrations, enhancing realism in food-inspired perfumery without being overpowering.
Safety Profile
GENERALLY SAFEWhat Does 2,5-Dimethylpyrazine Smell Like?
Opens with sharp roasted coffee grounds and dark chocolate bitterness, quickly softening into hazelnut spread warmth. The dry-down reveals subtle earthy tobacco leaf nuances. Like walking past a artisan coffee roastery where cocoa nibs are being ground – intense first impression that mellows into comforting gourmand embrace.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used at 0.2% to enhance the coffee accord, adding roasted depth that contrasts with white florals.
Provides the burnt sugar facet in the famous tar-and-coffee gourmand base.
2D Molecular Structure
SMILES: CC1=CN=C(C)C=N1
Chemistry, Properties & Perfumer Guide
The Chemistry
Pyrazine derivative with methyl groups at positions 2 and 5. Synthesized via condensation reactions of aminoketones. The planar aromatic ring system allows strong interaction with olfactory receptors. Methyl positioning creates steric hindrance that modulates volatility.
Physical & Chemical Properties
| Boiling Point | 155 °C |
|---|---|
| Vapor Pressure | 1.2 mmHg at 25°C |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.1-0.5% | Up to 1% | Overdosing creates harsh burnt notes |
| Functional Fragrance | 50-200 ppm | Up to 500 ppm | Coffee flavor enhancement |
Classic Accords
Tip: Counterbalance with sweet vanillic notes to prevent excessive bitterness.
Alternatives & Comparisons
More intense roasted character with higher olfactory threshold. Use when longer-lasting coffee effect is desired.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No restrictions under current IFRA standards.
RIFM Assessment
RIFM assessment confirms safe use at reported levels.
Sustainability
Synthesized from petrochemical precursors. Energy-intensive manufacturing offset by high potency requiring minimal quantities per formulation.
Explore 2,5-Dimethylpyrazine
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References
- PubChem Compound Summary for 2,5-Dimethylpyrazine CID 31257
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID6047652
Physical Properties
| Molecular Weight | 108.144 g/mol🔬 EPA CompTox |
| Density | 0.991 g/cm^3🔬 EPA CTX |
| Boiling Point | 155 °C🔬 EPA CTX |
| Melting Point | 15 °C🔬 EPA CTX |
| Flash Point | 63.975 °C🔬 EPA CTX |
| Refractive Index | 1.504 Dimensionless📊 OPERA |
| Molar Volume | 108.431 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 0.63 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 0.683 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 0.684 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 3.73 Log10 unitless📊 OPERA |
| Water Solubility | 3.064 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 1.5 mmHg🔬 EPA CTX |
| Viscosity | 1.873 cP📊 OPERA |
| Surface Tension | 36.448 dyn/cm📊 OPERA |
| Thermal Conductivity | 131.246 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 | 32.085 cm^3/mol📊 OPERA |
| Polarizability | 12.72 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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