4,7,7-Trimethyl-6-thiabicyclo[3.2.1]octane (CAS 68398-18-5) — Woody Top to Middle Note Fragrance Ingredient
4,7,7-Trimethyl-6-thiabicyclo[3.2.1]octane
CAS 68398-18-5
What Is 4,7,7-Trimethyl-6-thiabicyclo[3.2.1]octane?
4,7,7-Trimethyl-6-thiabicyclo[3.2.1]octane is a synthetic fragrance ingredient used to add unique sulfurous and woody nuances to perfumes. It’s found in niche fragrances seeking unconventional olfactory profiles. This compound matters because it bridges the gap between traditional woody notes and modern metallic/sulfurous accords, offering perfumers a tool for avant-garde compositions.
Safety Profile
USE WITH AWARENESSWhat Does 4,7,7-Trimethyl-6-thiabicyclo[3.2.1]octane Smell Like?
A striking juxtaposition of sulfidic intensity and dry woody backbone. Opens with a volatile burst reminiscent of struck flint and black pepper, evolving into a heart of charred cedar and roasted coffee beans. The dry-down reveals a lingering mineralic quality akin to hot stones after rain, with subtle camphoraceous undertones that prevent it from becoming overly aggressive.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used here to amplify the fragrance’s central smoke accord, adding a sulfurous edge that transforms the frankincense into something resembling burning rubber and sacred resins.
Employed as a molecular bridge between the sharp pepper top notes and the darker woody base, creating a continuous olfactory narrative from spice to embers.
2D Molecular Structure
SMILES: CC1CCC2CC1SC2(C)C
Chemistry, Properties & Perfumer Guide
The Chemistry
A bicyclic thioether with a unique bridged structure. The sulfur atom creates significant dipole moments and conformational constraints that contribute to its distinctive odor profile. Typically synthesized via thiol-ene reactions of appropriate terpene precursors, with the final structure offering remarkable stability against oxidation compared to simpler thioethers.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Molecular Weight | 184.32 g/mol |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Niche Fragrances | 0.1-0.5% | Up to 1% | Used for radical accents |
| Functional Fragrances | 0.01-0.1% | Trace amounts | For metallic nuances |
Classic Accords
Tip: Use with citrus or aldehydes to tame the sulfurous edge while preserving its character.
Alternatives & Comparisons
When a less aggressive sulfur note is desired, this oxathiane offers similar mineralic qualities with added fruity facets.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted by IFRA. Monitoring under 51st Amendment due to structural alerts.
GHS Classification
RIFM Assessment
Under review by RIFM. Preliminary data suggests moderate skin sensitization potential.
Sustainability
Synthetic production avoids natural resource depletion. The manufacturing process requires careful sulfur management to minimize environmental impact. Future green chemistry approaches may reduce energy requirements.
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References
- IFRA Standards Library – 51st Amendment IFRA 51
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID1052408
Physical Properties
| Molecular Weight | 170.31 g/mol🔬 EPA CompTox |
| Density | 0.936 g/cm^3📊 OPERA |
| Boiling Point | 210.729 °C📊 OPERA |
| Melting Point | 7.347 °C📊 OPERA |
| Flash Point | 74.947 °C📊 OPERA |
| Refractive Index | 1.493 Dimensionless📊 OPERA |
| Molar Volume | 180.835 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.801 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 3.801 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.801 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.57 Log10 unitless📊 OPERA |
| Water Solubility | 0.001 mol/L📊 OPERA |
| Henry's Law Constant | 0.008 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.351 mmHg📊 OPERA |
| Viscosity | 3.954 cP📊 OPERA |
| Surface Tension | 32.338 dyn/cm📊 OPERA |
| Thermal Conductivity | 100.011 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 0 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 1 count💻 Computed |
| Rotatable Bonds | 0 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 52.526 cm^3/mol📊 OPERA |
| Polarizability | 20.823 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.
