5-Methylquinoxaline (CAS 13708-12-8) — Woody Middle Note Fragrance Ingredient
5-Methylquinoxaline
CAS 13708-12-8
What Is 5-Methylquinoxaline?
5-Methylquinoxaline is a synthetic aroma chemical used in niche perfumery to create unique roasted, nutty, and coffee-like nuances. It’s found in avant-garde fragrances pushing olfactory boundaries. This molecule matters because it offers perfumers an unconventional tool to craft modern gourmand accords without relying on traditional vanilla or caramel notes.
Safety Profile
USE WITH AWARENESSWhat Does 5-Methylquinoxaline Smell Like?
5-Methylquinoxaline unfolds with an intense roasted character reminiscent of freshly ground coffee beans and toasted hazelnuts. The opening has a slightly bitter, almost burnt sugar edge that evolves into a warm, nutty heart. As it dries down, it reveals subtle earthy undertones akin to cocoa nibs and roasted barley. The overall effect is sophisticatedly savory rather than sweet, with a dry, woody finish that lingers like the aftertaste of dark chocolate.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used here to amplify the dark, resinous character with its roasted nuances, creating an illusion of cannabis smoke without actual cannabis notes.
Provides the coffee shop ambiance in this gourmand, blending with cardamom and cinnamon for a photorealistic Turkish coffee effect.
2D Molecular Structure
SMILES: CC1=CC=CC2=NC=CN=C12
Chemistry, Properties & Perfumer Guide
The Chemistry
5-Methylquinoxaline belongs to the heterocyclic aromatic compounds class, specifically diazanaphthalenes. While not found in nature, its structure resembles naturally occurring quinoxaline alkaloids. Industrially synthesized through condensation reactions of o-phenylenediamine with α-diketones, followed by methylation. The methyl group at position 5 creates a distinctive odor profile compared to other quinoxaline derivatives.
Physical & Chemical Properties
| Appearance | Pale yellow crystalline solid |
|---|---|
| Molecular Weight | 144.17 g/mol |
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 0.2% | Used sparingly in air care for coffee-like notes |
Classic Accords
Tip: Use in trace amounts with vanillin to create sophisticated coffee-chocolate effects without overwhelming sweetness.
Alternatives & Comparisons
Offers similar roasted notes but with more pronounced potato skin and nutty characteristics at lower detection thresholds.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted by IFRA standards. Listed as safe for use in current IFRA 51st Amendment guidelines.
RIFM Assessment
Under review by RIFM for comprehensive safety assessment. Preliminary data suggests low skin sensitization potential.
Sustainability
As a synthetic material, 5-Methylquinoxaline has minimal environmental impact during production. Its high potency means very small quantities are needed, reducing overall chemical load in formulations compared to natural coffee absolutes.
Explore 5-Methylquinoxaline
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References
- Burdock, G.A. (2010). Fenaroli’s Handbook of Flavor Ingredients. CRC Press. ISBN 9781420090869
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 13708-12-8Physical Properties
| Molecular Weight | 144.17 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 2🔬 PubChem |
| Boiling Point | 245 °C🔬 EPA CompTox |
| Vapor Pressure | 0.0004 mmHg @ 25°C📊 OPERA |
| Flash Point | 108.8 °C🔬 EPA CompTox |
| log Kp (skin permeability) | -2.159💻 Calculated |
| SMILES | CC1=C2C(=CC=C1)N=CC=N2🔬 PubChem |
Volatility & Performance
| Fragrance Note | Base💻 Calculated |
| Volatility Class | Very slow💻 Calculated |
| Persistence Score | 5.1 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | burntnuttyroasted• leffingwell |
| Functional Groups | aromatic💻 RDKit |
| 5-Methylquinoxaline has a burnt, roasted, nutty, roasted corn, coffee odor.📖 Fenaroli | |
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: DTXSID4047090
Physical Properties
| Molecular Weight | 144.177 g/mol🔬 EPA CompTox |
| Density | 1.115 g/cm^3🔬 EPA CTX |
| Boiling Point | 245 °C🔬 EPA CTX |
| Melting Point | 20.8 °C🔬 EPA CTX |
| Flash Point | 111.14 °C📊 OPERA |
| Refractive Index | 1.633 Dimensionless📊 OPERA |
| Molar Volume | 126.272 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 2.04 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 1.972 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 1.972 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.75 Log10 unitless📊 OPERA |
| Water Solubility | 0.114 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.019 mmHg📊 OPERA |
| Viscosity | 8.148 cP📊 OPERA |
| Surface Tension | 44.129 dyn/cm📊 OPERA |
| Thermal Conductivity | 130.954 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 | 2 count💻 Computed |
| Molar Refractivity | 45.103 cm^3/mol📊 OPERA |
| Polarizability | 17.88 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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