5,6,7,8-Tetrahydroquinoxaline (CAS 34413-35-9) — Green Heart Note Fragrance Ingredient
5,6,7,8-Tetrahydroquinoxaline
CAS 34413-35-9
What Is 5,6,7,8-Tetrahydroquinoxaline?
5,6,7,8-Tetrahydroquinoxaline is a synthetic aroma chemical used in niche perfumery. It’s found in some modern fragrances seeking unusual earthy-green effects. This ingredient matters because it offers perfumers a unique tool for creating complex, intellectual scents that challenge traditional fragrance structures.
Safety Profile
USE WITH AWARENESSWhat Does 5,6,7,8-Tetrahydroquinoxaline Smell Like?
5,6,7,8-Tetrahydroquinoxaline presents an intriguing olfactory paradox – simultaneously earthy like damp forest soil yet with a sharp, almost metallic greenness reminiscent of crushed stems. The initial impression is intensely vegetal, evolving into a dry, papery character with hints of tobacco leaf. In drydown, it leaves a subtle mineralic trace, like wet stones warmed by sunlight. Its persistence is moderate, working best when paired with materials that can soften its angular edges.
2D Molecular Structure
SMILES: C1CCC2=NC=CN=C2C1
Chemistry, Properties & Perfumer Guide
The Chemistry
5,6,7,8-Tetrahydroquinoxaline belongs to the quinoxaline class of heterocyclic compounds, characterized by a benzene ring fused to a pyrazine ring. As a synthetic material, it’s produced through catalytic hydrogenation of quinoxaline derivatives. The partially saturated structure contributes to its distinctive odor profile, with the nitrogen atoms playing a key role in its binding to olfactory receptors. Its molecular rigidity gives it excellent stability in fragrance formulations.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Solubility | Soluble in alcohol, insoluble in water |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.1-0.5% | Up to 1% | Used as an accent material |
| Functional Fragrance | Trace | Up to 0.1% | Rarely used |
Classic Accords
Tip: Use sparingly in chypre or fougère bases to add intellectual depth.
Alternatives & Comparisons
Offers similar earthy notes but with more nutty character and better blending properties.
Provides comparable green-leather effects but with greater diffusion and tenacity.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted by IFRA standards.
RIFM Assessment
No formal RIFM evaluation available. Use recommended at low levels pending further studies.
Sustainability
As a synthetic material, 5,6,7,8-Tetrahydroquinoxaline has minimal environmental impact in production. Its high potency means small quantities suffice, reducing overall material usage. The synthesis route typically employs green chemistry principles with good atom economy.
Explore 5,6,7,8-Tetrahydroquinoxaline
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References
- Burdock, G.A. (2010). Fenaroli’s Handbook of Flavor Ingredients. CRC Press.
- Arctander, S. (1969). Perfume and Flavor Chemicals. Allured Publishing.
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 34413-35-9Physical Properties
| Molecular Weight | 134.18 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 0.9🔬 PubChem |
| Boiling Point | 108 °C🔬 EPA CompTox |
| log Kp (skin permeability) | -2.879💻 Calculated |
| SMILES | C1CCC2=NC=CN=C2C1🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
Odor & Flavor
| Primary Descriptors | nuttyroasted• leffingwell |
| Functional Groups | aromatic💻 RDKit |
| “/cTcH The material resembles para-Methylquino- z Iine with respect to odor, but it has not o become nearly as well known or popular in \~,&H, perfumery. o This quinoline is rarely offered commercial- COHIIN = 133.20 ly, and it could be because of the mentioned lack of “softness” in its initial odor. Rather rough or harsh-caramellic-Honey- like, sweet odor with discrete animal character.”📖 Arctander | |
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: DTXSID4047678
Physical Properties
| Molecular Weight | 134.182 g/mol🔬 EPA CompTox |
| Density | 1.077 g/cm^3🔬 EPA CTX |
| Boiling Point | 109.5 °C🔬 EPA CTX |
| Melting Point | 29.5 °C🔬 EPA CTX |
| Flash Point | 94.088 °C📊 OPERA |
| Refractive Index | 1.552 Dimensionless📊 OPERA |
| Molar Volume | 122.71 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 1.46 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 1.46 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 1.46 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.06 Log10 unitless📊 OPERA |
| Water Solubility | 0.297 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.038 mmHg📊 OPERA |
| Viscosity | 6.69 cP📊 OPERA |
| Surface Tension | 41.472 dyn/cm📊 OPERA |
| Thermal Conductivity | 134.856 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 | 39.221 cm^3/mol📊 OPERA |
| Polarizability | 15.549 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.
