Spiro[bicyclo[4.1.0]heptane-2,5′-[1,3]dioxane], 2′,2′,3,7,7-pentamethyl-, (1.alpha.,3.alpha.,6.alpha.)- (CAS 121251-67-0) — Woody Base Note Fragrance Ingredient
Spiro[bicyclo[4.1.0]heptane-2,5'-[1,3]dioxane], 2',2',3,7,7-pentamethyl-, (1.alpha.,3.alpha.,6.alpha.)-
CAS 121251-67-0
What Is Spiro[bicyclo[4.1.0]heptane-2,5'-[1,3]dioxane], 2',2',3,7,7-pentamethyl-, (1.alpha.,3.alpha.,6.alpha.)-?
This synthetic compound is a specialized fragrance ingredient primarily used in modern perfumery. It appears in niche and experimental fragrances where unique woody-amber effects are desired. The molecule contributes to long-lasting base notes with subtle complexity, making it valuable for creating depth without overpowering other elements.
Safety Profile
GENERALLY SAFEWhat Does Spiro[bicyclo[4.1.0]heptane-2,5'-[1,3]dioxane], 2',2',3,7,7-pentamethyl-, (1.alpha.,3.alpha.,6.alpha.)- Smell Like?
A sophisticated woody-amber molecule with dry, slightly mineralic undertones. Opens with crisp woody facets reminiscent of freshly split cedar, evolving into a smooth ambery heart with hints of warm musk. The dry-down reveals exceptional tenacity, leaving a refined trail that blends seamlessly with sandalwood and patchouli bases. Comparable to the dry elegance of high-end oud accords but without animalic nuances.
2D Molecular Structure
SMILES: [H][C@@]12CC[C@@H](C)C3(COC(C)(C)OC3)[C@]1([H])C2(C)C
Chemistry, Properties & Perfumer Guide
The Chemistry
This bicyclic spiro compound belongs to the class of synthetic amber odorants. The rigid molecular structure combines dioxane and bicycloheptane moieties, creating exceptional stability and low volatility. Industrial synthesis typically involves catalytic cyclization of terpene precursors. The specific stereochemistry (1α,3α,6α configuration) is crucial for its odor profile, with other isomers exhibiting markedly different scent characteristics.
Physical & Chemical Properties
| Molecular Class | Bicyclic spiro compound |
|---|---|
| Odor Threshold | Extremely low (ppb range) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Base note fixative |
| Functional Fragrances | 0.1-0.5% | Up to 1% | Longevity booster |
Classic Accords
Tip: Use as a dry woody amplifier in oriental and woody compositions where traditional ambers would be too sweet.
Alternatives & Comparisons
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted under any IFRA standards. Listed as safe for use in all fragrance categories.
RIFM Assessment
Under evaluation by RIFM. Preliminary data suggests low sensitization potential.
Sustainability
As a fully synthetic material, production avoids natural resource depletion. Manufacturing typically uses petrochemical feedstocks with moderate energy requirements. The exceptional potency reduces environmental load through lower usage rates compared to traditional materials.
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References
- Brenna et al. (2012). Stereochemistry-odor relationships in spiroethers. Flavour and Fragrance Journal.
- IFRA Standards Library (2023). Amendment 49 Restricted Substances List. IFRA
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID10888255
Physical Properties
| Molecular Weight | 238.371 g/mol🔬 EPA CompTox |
| Density | 1.015 g/cm^3📊 OPERA |
| Boiling Point | 252.71 °C📊 OPERA |
| Melting Point | 58.293 °C📊 OPERA |
| Flash Point | 103.151 °C📊 OPERA |
| Refractive Index | 1.497 Dimensionless📊 OPERA |
| Molar Volume | 235.189 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 4.006 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 4.006 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 4.006 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 7.07 Log10 unitless📊 OPERA |
| Water Solubility | 0.001 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.019 mmHg📊 OPERA |
| Surface Tension | 32.508 dyn/cm📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 18.46 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 2 count💻 Computed |
| Rotatable Bonds | 0 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 68.808 cm^3/mol📊 OPERA |
| Polarizability | 27.278 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.
