Methoxypyrazine (CAS 3149-28-8) — Green Top to Heart Note Fragrance Ingredient
Methoxypyrazine
CAS 3149-28-8
What Is Methoxypyrazine?
Methoxypyrazines are powerful aroma compounds that occur naturally in some vegetables and wine grapes, but are also synthesized for perfumery. They’re responsible for the characteristic ‘green bell pepper’ or ‘earthy’ notes in certain fragrances and wines. These molecules are prized in perfumery for their ability to add ultra-realistic vegetal nuances at extremely low concentrations, often measured in parts per million.
Safety Profile
USE WITH AWARENESSWhat Does Methoxypyrazine Smell Like?
Methoxypyrazines hit the nose with an intensely green, vegetal explosion – think freshly cut bell peppers, crushed vine leaves, or the sappy steminess of just-picked tomatoes. The aroma persists stubbornly, evolving into earthier, almost mineralic nuances over time. At higher concentrations, they can smell like damp soil or even the musky underside of forest mushrooms. Their tenacity makes them excellent fixatives despite their volatile nature, anchoring green accords with a razor-sharp precision.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
This groundbreaking green floral used pyrazines to create its hyper-realistic crushed leaves effect, revolutionizing vegetal accords in perfumery.
A tomato leaf soliflore where pyrazines provide the photorealistic garden freshness that defines this cult classic.
2D Molecular Structure
SMILES: COC1=NC=CN=C1
Chemistry, Properties & Perfumer Guide
The Chemistry
Methoxypyrazines belong to the heterocyclic nitrogen compounds, characterized by a pyrazine ring with methoxy substitutions. While found naturally in plants like bell peppers and Cabernet Sauvignon grapes, perfumery uses synthetic versions for consistency. The 2-methoxy-3-isobutylpyrazine isomer is most significant, detectable by humans at concentrations as low as 2 parts per trillion. Synthesis typically involves condensation reactions of α-diketones with amino acids, followed by methoxylation.
Physical & Chemical Properties
| Detection Threshold | 0.002 ppt in air |
|---|---|
| Typical Use Level | 0.0001-0.001% |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.0005% | 0.0001-0.002% | Extremely potent – measure carefully |
| Functional Fragrance | 0.0001% | trace-0.0003% | For realistic green nuances |
| Flavoring | 0.00001% | trace-0.00005% | Wine and vegetable flavors |
Classic Accords
Tip: Always pre-dilute to 0.1% or lower before incorporating into blends due to extreme potency.
Alternatives & Comparisons
Provides similar green stemmy effects but with less vegetal intensity and better blending properties for floral compositions.
Offers fresh green leaf character without the pyrazine’s potentially overwhelming bell pepper aspects at higher concentrations.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No specific IFRA restrictions, but extreme potency warrants caution in formulations.
GHS Classification
RIFM Assessment
RIFM evaluation confirms safety at current use levels in fragrances.
Sustainability
Synthetic production avoids agricultural sourcing challenges, though energy-intensive chemistry is required. Recent advances in biocatalysis may offer greener synthesis routes. The extreme potency means very small quantities satisfy demand, reducing overall environmental impact per kilogram of finished product.
Explore Methoxypyrazine
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References
- Maga, J.A. (1975). Pyrazines in Foods. CRC Critical Reviews in Food Technology. DOI
- Allen, M.S. et al. (1991). Contribution of Methoxypyrazines to Sauvignon Blanc Wine Aroma. ACS
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorLayer 3 · Practical
- Odor Profile: cocoa, earthy, green, nutty, roasted, sweet, winey
- FEMA GRAS: 3302
- Molecular Weight: 110.11 g/mol
- LogP (XLogP): 0.70
Ingredient Data Sheet
CAS 3149-28-8Physical Properties
| Molecular Weight | 110.11 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 0.7🔬 PubChem |
| Boiling Point | 60 °C🔬 EPA CompTox |
| log Kp (skin permeability) | -2.875💻 Calculated |
| SMILES | COC1=NC=CN=C1🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
Odor & Flavor
| Primary Descriptors | earthygreennuttyroastedsweet• leffingwell |
| Functional Groups | etheraromatic💻 RDKit |
| Methoxypyrazine has a sweet, nutty, cocoa odor. Methoxypyrazine contributes a distinctive “green, capsicum (bell pepper), herbaceous and earthy” aroma that is quite characteristic of certain wines, such as sauvignon blanc and cabernet sauvignon.📖 Fenaroli | |
Sensory Thresholds
| Odor Detection Threshold | 0.7 ppm📖 van Gemert |
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: DTXSID4047676
Physical Properties
| Molecular Weight | 110.116 g/mol🔬 EPA CompTox |
| Density | 1.14 g/cm^3🔬 EPA CTX |
| Boiling Point | 154.263 °C📊 OPERA |
| Melting Point | 32.922 °C📊 OPERA |
| Flash Point | 54.414 °C📊 OPERA |
| Refractive Index | 1.495 Dimensionless📊 OPERA |
| Molar Volume | 99.883 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 0.73 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 0.894 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 0.894 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 3.95 Log10 unitless📊 OPERA |
| Water Solubility | 1.879 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 2.247 mmHg📊 OPERA |
| Viscosity | 2.12 cP📊 OPERA |
| Surface Tension | 37.536 dyn/cm📊 OPERA |
| Thermal Conductivity | 137.538 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 35.01 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 3 count💻 Computed |
| Rotatable Bonds | 1 count💻 Computed |
| Aromatic Rings | 1 count💻 Computed |
| Molar Refractivity | 29.114 cm^3/mol📊 OPERA |
| Polarizability | 11.542 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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