(2.alpha.,4a.alpha.,8.alpha.)-Hexahydro-1,1,5,5-tetramethyl-2H-2,4a-methanonaphthalen-8(5H)-one (CAS 29461-14-1) — Woody Base Note Fragrance Ingredient

Woody · Balsamic

(2.alpha.,4a.alpha.,8.alpha.)-Hexahydro-1,1,5,5-tetramethyl-2H-2,4a-methanonaphthalen-8(5H)-one

CAS 29461-14-1

Origin
synthetic
Note
Base
IFRA
Use with awareness
Data as of: Apr 2026

What Is (2.alpha.,4a.alpha.,8.alpha.)-Hexahydro-1,1,5,5-tetramethyl-2H-2,4a-methanonaphthalen-8(5H)-one?

This synthetic fragrance ingredient is a complex ketone used in modern perfumery. It’s typically found in niche and artisanal fragrances seeking unique woody-ambery effects. While not widely recognized by name, it contributes to sophisticated scent profiles that consumers encounter in premium products.

Safety Profile

USE WITH AWARENESS
Generally safeUse with awarenessProfessional use
Not currently IFRA restricted
Safety data limited – use moderate concentrations
CAS
29461-14-1
Formula
Mixture
MW
Variable
Odor Family
Woody · Balsamic
Layer 1 · Enthusiast

What Does (2.alpha.,4a.alpha.,8.alpha.)-Hexahydro-1,1,5,5-tetramethyl-2H-2,4a-methanonaphthalen-8(5H)-one Smell Like?

A sophisticated woody-amber molecule with a complex olfactory profile. Opens with crisp camphoraceous facets that quickly evolve into a rich, dry cedarwood character with subtle leathery undertones. The dry-down reveals a smooth ambery warmth with hints of tobacco-like richness. Exceptionally tenacious, it provides excellent diffusion and longevity while maintaining clarity throughout the fragrance evolution.

Scent Profile
Layer 2

2D Molecular Structure

rel-(2R,4aR,8aR)-Hexahydro-1,1,5,5-tetramethyl-2H-2,4a-methanonaphthalen-8(5H)-one

SMILES: [H][C@@]12C(=O)CCC(C)(C)[C@]11CC[C@@H](C1)C2(C)C

Chemistry, Properties & Perfumer Guide

The Chemistry

This bicyclic ketone belongs to the family of decalin derivatives with a complex bridged ring structure. The molecule features multiple quaternary carbons contributing to its stability and tenacity. Synthesized through Diels-Alder reactions of appropriate terpene precursors followed by oxidation, it represents a modern approach to creating durable woody-amber notes. The rigid molecular framework prevents rapid volatilization while allowing excellent diffusion.

Physical & Chemical Properties

Perfumer Guide

Note Position
Base
Volatility
Very low (24+ hours)
Blending
Good
ApplicationTypical %RangeNotes
Fine Fragrance0.5-2%Up to 5%Foundation for woody accords
Home Fragrance1-3%Up to 8%Provides longevity

Classic Accords

Tip: Use with ionones to soften sharp edges while maintaining projection.

Alternatives & Comparisons

1
Ambrox CAS 6790-58-5

For similar tenacity with cleaner ambery character

2
Norlimbanol CAS 70788-30-6

When more pronounced woody-dry effects are desired

Layer 3

Safety, Regulatory & Sustainability

⚠ Regulatory Disclaimer

General reference only. Consult current IFRA Standards Library before formulating.

IFRA Status

No current IFRA restrictions. Not evaluated under latest amendments.

RIFM Assessment

Not currently evaluated by RIFM. Limited toxicological data available.

Sustainability

As a purely synthetic material, this ingredient avoids natural resource depletion concerns. However, its complex synthesis may involve multi-step processes with moderate environmental impact. Modern green chemistry approaches are being explored to optimize production efficiency.

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References

    Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.

    Report a data error

    Physicochemical Properties

    DTXSID: DTXSID5047168

    Physical Properties

    Molecular Weight 220.356 g/mol🔬 EPA CompTox
    Density 1.002 g/cm^3🔬 EPA CTX
    Boiling Point 295.9 °C🔬 EPA CTX
    Melting Point -22 °C🔬 EPA CTX
    Flash Point 134.28 °C🔬 EPA CTX
    Refractive Index 1.509 Dimensionless📊 OPERA
    Molar Volume 219.2 cm^3/mol📊 OPERA

    Partition & Solubility

    LogP (Octanol-Water) 4.905 Log10 unitless🔬 EPA CTX
    LogD (pH 5.5) 4.111 Log10 unitless📊 OPERA
    LogD (pH 7.4) 4.111 Log10 unitless📊 OPERA
    LogKoa (Octanol-Air) 7.26 Log10 unitless📊 OPERA
    Water Solubility 0 mol/L🔬 EPA CTX
    Henry's Law Constant 0 atm-m3/mole📊 OPERA

    Transport Properties

    Vapor Pressure 0.011 mmHg🔬 EPA CTX
    Surface Tension 34.347 dyn/cm📊 OPERA
    Thermal Conductivity 110.947 mW/(m*K)📊 OPERA

    Molecular Descriptors

    Topological Polar Surface Area 17.07 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 65.464 cm^3/mol📊 OPERA
    Polarizability 25.952 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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