Pyrazine, 2-methyl-6-propoxy (CAS 67845-28-7) — Sweet Middle to base Note Fragrance Ingredient
Pyrazine, 2-methyl-6-propoxy
CAS 67845-28-7
What Is Pyrazine, 2-methyl-6-propoxy?
2-methyl-6-propoxy pyrazine is a synthetic aroma chemical that creates a roasted, nutty scent. You might encounter it in gourmand fragrances or savory food flavorings. This molecule is prized for its ability to add depth and complexity to fragrances, mimicking the smell of roasted peanuts, coffee, or toasted bread. It’s particularly useful in modern perfumery for creating unconventional, edible-inspired accords.
Safety Profile
USE WITH AWARENESSWhat Does Pyrazine, 2-methyl-6-propoxy Smell Like?
This pyrazine derivative delivers an intensely roasted character – imagine fresh coffee beans ground with peanut skins, or the crust of sourdough bread pulled straight from the oven. The propoxy side chain softens the typical pyrazine sharpness, adding a buttery richness that evolves into a warm, nutty heart. In drydown, it leaves a subtle savory trace like toasted sesame oil, making it excellent for gourmand bases. The effect is more refined than simpler alkylpyrazines, with better blending potential in complex compositions.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used here to create the illusion of dark roasted coffee beans, blending with rum and caramel notes for an intoxicating gourmand effect.
Provides a subtle toasted bread nuance that grounds the iris and honey accord, adding comforting warmth.
2D Molecular Structure
SMILES: CCCOC1=NC(C)=CN=C1
Chemistry, Properties & Perfumer Guide
The Chemistry
As an alkoxypyrazine, this molecule features a propoxy group at the 6-position and methyl at the 2-position on the pyrazine ring. The electron-donating propoxy group decreases the nitrogen’s basicity compared to unsubstituted pyrazines, resulting in a less aggressive odor profile. Synthesis typically involves nucleophilic aromatic substitution on chloropyrazine precursors. While not found in nature, its odor profile mimics Maillard reaction products from roasted foods.
Physical & Chemical Properties
| Appearance | Clear to pale yellow liquid |
|---|---|
| Odor Threshold | Extremely low (ppb range) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.1-0.5% | Up to 1% | Powerful modifier for gourmand accords |
| Functional Fragrance | 0.01-0.1% | Up to 0.3% | Used sparingly in air care products |
Classic Accords
Tip: Stabilize in ethanol before blending to prevent uneven distribution due to low solubility.
Alternatives & Comparisons
More vegetal (bell pepper) character, useful when sharper green notes are desired rather than roasted effects.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted by IFRA. Self-limiting due to potency.
RIFM Assessment
No specific RIFM evaluation published, but structurally similar pyrazines have good safety profiles at typical use levels.
Sustainability
As a synthetic material, production avoids agricultural land use. Manufacturing requires careful control of nitrogen-containing waste streams. More sustainable than some natural pyrazine sources that require extensive plant material processing.
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Physicochemical Properties
DTXSID: DTXSID2070685
Physical Properties
| Density | 1.019 g/cm^3📊 OPERA |
| Boiling Point | 205.706 °C📊 OPERA |
| Melting Point | 32.398 °C📊 OPERA |
| Flash Point | 79.837 °C📊 OPERA |
| Refractive Index | 1.491 Dimensionless📊 OPERA |
| Molar Volume | 149.172 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 2.29 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 2.17 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 2.19 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.06 Log10 unitless📊 OPERA |
| Water Solubility | 0.064 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.172 mmHg📊 OPERA |
| Viscosity | 3.519 cP📊 OPERA |
| Surface Tension | 36.427 dyn/cm📊 OPERA |
| Thermal Conductivity | 134.956 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 | 3 count💻 Computed |
| Aromatic Rings | 1 count💻 Computed |
| Molar Refractivity | 43.205 cm^3/mol📊 OPERA |
| Polarizability | 17.128 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.
