6-Methyl-7oxa-1-thia-4-azaspiro(4,4)nonane (CAS 165261-13-2) — Musky Base Note Fragrance Ingredient
6-Methyl-7oxa-1-thia-4-azaspiro(4,4)nonane
CAS 165261-13-2
What Is 6-Methyl-7oxa-1-thia-4-azaspiro(4,4)nonane?
6-Methyl-7oxa-1-thia-4-azaspiro(4,4)nonane is a synthetic fragrance ingredient used in modern perfumery to create unique olfactory effects. It’s found in niche and avant-garde fragrances. This compound matters because it represents cutting-edge perfumery, allowing creators to design novel scent experiences that can’t be achieved with traditional materials.
Safety Profile
PROFESSIONAL USEWhat Does 6-Methyl-7oxa-1-thia-4-azaspiro(4,4)nonane Smell Like?
This synthetic molecule offers a complex olfactory profile – initially presenting with a sharp, metallic edge that evolves into a warm, slightly animalic musk with hints of burnt rubber and leather. The dry-down reveals subtle woody-ambery facets, making it an intriguing base for modern fragrances. Its unusual structure creates a diffusive, long-lasting effect that perfumers value for adding cutting-edge character to compositions.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
This minimalist fragrance showcases the material’s unique metallic-musk character, creating an avant-garde scent experience that evolves intriguingly on skin.
Used here to enhance the dark, resinous qualities with its animalic edge, adding depth to the oud and cannabis accord.
2D Molecular Structure
SMILES: CC1OCCC11NCCS1
Chemistry, Properties & Perfumer Guide
The Chemistry
6-Methyl-7oxa-1-thia-4-azaspiro(4,4)nonane is a synthetic sulfur-containing heterocyclic compound with a unique spiro structure. Its molecular architecture combines oxygen, sulfur, and nitrogen atoms in a constrained ring system that contributes to its distinctive olfactory properties. The compound is synthesized through specialized organic reactions that construct its complex bicyclic framework. The presence of multiple heteroatoms creates strong dipole moments that influence both its physical properties and scent characteristics.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Molecular Weight | Not publicly available |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.1-0.5% | Up to 1% | Used as a special effect |
| Functional Fragrance | Not used | N/A | Not suitable for consumer products |
Classic Accords
Tip: Use sparingly in avant-garde compositions where a metallic-animalic nuance is desired.
Alternatives & Comparisons
Offers a smoother musk-woody effect without the sharp metallic character, suitable when a more wearable base is needed.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Usage restricted under IFRA guidelines for professional perfumery only (Amendment 49).
GHS Classification
RIFM Assessment
Under review by RIFM for comprehensive safety assessment.
Sustainability
As a synthetic material, this compound is produced through controlled chemical processes with minimal environmental impact. Its high potency means very small quantities are needed in formulations, reducing overall material usage. However, specialized synthesis requirements may involve energy-intensive steps.
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References
- IFRA Standards Library Amendment 49 IFRA Standards
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 165261-13-2Physical Properties
| Molecular Weight | 159.25 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 0.6🔬 PubChem |
| Boiling Point | 227 °C🔬 EPA CompTox |
| Vapor Pressure | 0.002 mmHg @ 25°C📊 OPERA |
| Flash Point | 124.5 °C🔬 EPA CompTox |
| Involatility Index | 0.0002💻 Calculated |
| log Kp (skin permeability) | -3.245💻 Calculated |
| SMILES | CC1C2(CCO1)NCCS2🔬 PubChem |
Volatility & Performance
| Fragrance Note | Base💻 Calculated |
| Volatility Class | Very slow💻 Calculated |
| Persistence Score | 3.3 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | muskywoody• leffingwell |
| Functional Groups | etheramine💻 RDKit |
| “Penetrating and heavy, but in dilution floral, sweet-animal odor of good tenacity.”📖 Arctander | |
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: DTXSID80889052
Physical Properties
| Molecular Weight | 159.25 g/mol🔬 EPA CompTox |
| Density | 1.14 g/cm^3📊 OPERA |
| Boiling Point | 229.501 °C📊 OPERA |
| Melting Point | 81.146 °C📊 OPERA |
| Flash Point | 106.072 °C📊 OPERA |
| Refractive Index | 1.556 Dimensionless📊 OPERA |
| Molar Volume | 136.178 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 1.068 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 0.313 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 1.021 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 7.51 Log10 unitless📊 OPERA |
| Water Solubility | 0.402 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.013 mmHg📊 OPERA |
| Viscosity | 7.755 cP📊 OPERA |
| Surface Tension | 39.281 dyn/cm📊 OPERA |
| Thermal Conductivity | 142.828 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 21.26 Ų💻 Computed |
| H-Bond Donors | 1 count💻 Computed |
| H-Bond Acceptors | 3 count💻 Computed |
| Rotatable Bonds | 0 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 43.761 cm^3/mol📊 OPERA |
| Polarizability | 17.348 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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