3a,4,5,6,7,7a-Hexahydro-5-methoxy-4,7-methano-1H-indene (CAS 53018-24-9) — Woody Middle to base Note Fragrance Ingredient
3a,4,5,6,7,7a-Hexahydro-5-methoxy-4,7-methano-1H-indene
CAS 53018-24-9
What Is 3a,4,5,6,7,7a-Hexahydro-5-methoxy-4,7-methano-1H-indene?
This synthetic fragrance ingredient is a complex molecule used in modern perfumery to create unique woody-ambery effects. You’ll find it in niche and avant-garde fragrances pushing olfactory boundaries. It matters because it represents perfumery’s ability to engineer novel scent experiences beyond traditional natural materials, offering perfumers unprecedented creative control.
Safety Profile
USE WITH AWARENESSWhat Does 3a,4,5,6,7,7a-Hexahydro-5-methoxy-4,7-methano-1H-indene Smell Like?
A sophisticated synthetic with a paradoxical duality – simultaneously woody and ethereal. Opens with crisp camphoraceous facets reminiscent of antique wooden chests, evolving into a heart of smooth ambered warmth with subtle metallic undertones. The dry-down reveals an almost mineralic purity, like sun-warmed stones in a pine forest. Exceptionally diffusive with excellent tenacity, it behaves like a chameleon – amplifying woody notes in one context while enhancing ambers in another.
2D Molecular Structure
SMILES: COC1CC2CC1C1C=CCC21
Chemistry, Properties & Perfumer Guide
The Chemistry
This bicyclic ether belongs to the family of synthetic amber chemicals derived from modified terpene structures. The methoxy group at position 5 contributes significantly to its odor profile. Synthesized through Diels-Alder reactions followed by selective oxidation and etherification steps, its rigid molecular architecture creates exceptional stability. The stereochemistry at the methano bridge positions influences its olfactory characteristics, with different isomers exhibiting varying intensity and tonal qualities.
Physical & Chemical Properties
| Molecular Complexity | High |
|---|---|
| Structural Class | Bicyclic ether |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Used as sophisticated woody-amber modifier |
| Functional Fragrance | 0.1-0.5% | Up to 1% | For premium woody fabric care products |
Classic Accords
Tip: Use in trace amounts to add dimensionality to woody bases without overwhelming the composition.
Alternatives & Comparisons
More ambery and less woody, suitable when seeking warmer dry-down characteristics.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted under any IFRA amendment.
RIFM Assessment
Under evaluation by RIFM as part of novel synthetic materials assessment program.
Sustainability
As a fully synthetic material, its production avoids natural resource depletion but requires petrochemical feedstocks. Recent advances in catalytic processes have improved atom economy in its synthesis. Being highly potent, it requires minimal quantities per formulation, reducing overall environmental burden compared to some natural alternatives.
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Ingredient Data Sheet
CAS 53018-24-9Physical Properties
| Molecular Weight | 164.24 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 2.1🔬 PubChem |
| Boiling Point | 219.1 °C🔬 EPA CompTox |
| Vapor Pressure | 0.39 mmHg @ 25°C📊 OPERA |
| Flash Point | 86 °C🔬 EPA CompTox |
| Involatility Index | 0.0328💻 Calculated |
| log Kp (skin permeability) | -2.211💻 Calculated |
| SMILES | COC1CC2CC1C3C2CC=C3🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
| Volatility Class | Slow💻 Calculated |
| Persistence Score | 0.6 / 5💻 Calculated |
Odor & Flavor
| Functional Groups | etheralkene💻 RDKit |
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: DTXSID10866295
Physical Properties
| Molecular Weight | 164.248 g/mol🔬 EPA CompTox |
| Density | 1.01 g/cm^3🔬 EPA CTX |
| Boiling Point | 219.1 °C🔬 EPA CTX |
| Melting Point | 53.608 °C📊 OPERA |
| Flash Point | 86 °C🔬 EPA CTX |
| Refractive Index | 1.53 Dimensionless📊 OPERA |
| Molar Volume | 156.751 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3876.925 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 3.61 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.61 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.22 Log10 unitless📊 OPERA |
| Water Solubility | 0.001 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.499 mmHg🔬 EPA CTX |
| Viscosity | 6.393 cP📊 OPERA |
| Surface Tension | 34.474 dyn/cm📊 OPERA |
| Thermal Conductivity | 111.413 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 9.23 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 1 count💻 Computed |
| Rotatable Bonds | 1 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 48.387 cm^3/mol📊 OPERA |
| Polarizability | 19.182 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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