2,3,4,4a,5,6,7,8-Octahydro-2,5,5-trimethyl-2-naphtol (CAS 643-53-8) — Woody Middle to base Note Fragrance Ingredient

ByThe Good Scents
Woody · Balsamic

2,3,4,4a,5,6,7,8-Octahydro-2,5,5-trimethyl-2-naphtol

CAS 643-53-8

Origin
synthetic
Note
Middle to base
IFRA
Use with awareness
Data as of: Apr 2026

What Is 2,3,4,4a,5,6,7,8-Octahydro-2,5,5-trimethyl-2-naphtol?

This synthetic fragrance ingredient is a complex woody-alcohol compound primarily used by professional perfumers. Consumers may encounter it in niche woody or amber fragrances where it contributes depth. Its importance lies in providing a stable, long-lasting woody note that blends well with both natural and synthetic components.

Safety Profile

USE WITH AWARENESS
Generally safeUse with awarenessProfessional use
✓ Stable under normal use conditions
⚠ Limited toxicological data available
CAS
643-53-8
Formula
Mixture
MW
Variable
Odor Family
Woody · Balsamic
Layer 1 · Enthusiast

What Does 2,3,4,4a,5,6,7,8-Octahydro-2,5,5-trimethyl-2-naphtol Smell Like?

A sophisticated woody-alcohol with a dry, slightly camphoraceous opening that evolves into a smooth sandalwood-like heart. The dry-down reveals subtle amber facets with exceptional tenacity. Imagine aged oak barrels meeting freshly planed cedarwood, with a whisper of dry tobacco leaves in the background. Its odor profile bridges the gap between sharp woody top notes and warm base materials.

Scent Profile
Layer 2

2D Molecular Structure

2-Naphthalenol, 2,3,4,4a,5,6,7,8-octahydro-2,5,5-trimethyl-

SMILES: CC1(C)CCCC2=CC(C)(O)CCC12

Chemistry, Properties & Perfumer Guide

The Chemistry

This bicyclic tertiary alcohol belongs to the decalin-derived fragrance alcohols class. Synthesized through hydrogenation of appropriate naphthalene precursors followed by hydroxylation. The rigid bicyclic structure contributes to its stability and diffusion properties. The three methyl groups create steric hindrance that modulates volatility.

Physical & Chemical Properties

Molecular ClassBicyclic tertiary alcohol
Structural FeaturesRigid decalin core with three methyl groups

Perfumer Guide

Note Position
Middle to base
Volatility
Moderate (2-6 hours)
Blending
Good
ApplicationTypical %RangeNotes
Fine Fragrance0.5-2%Up to 5%Woody-amber base note
Functional Fragrance0.1-1%Up to 3%Stabilizing woody note

Classic Accords

Tip: Use to add woody depth without excessive dryness in amber compositions.

Alternatives & Comparisons

1
Sandalwood EO CAS 8006-87-9

For natural woody profiles when cost allows, though less stable.

2
Ebanol CAS 14528-94-2

Similar woody-alcohol character with more pronounced sandalwood facets.

Layer 3

Safety, Regulatory & Sustainability

⚠ Regulatory Disclaimer

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

IFRA Status

Not currently restricted by IFRA standards.

RIFM Assessment

Limited safety assessment available through RIFM databases.

Sustainability

As a synthetic material, production avoids natural resource depletion. Manufacturing typically involves petrochemical feedstocks, though newer green chemistry routes may reduce environmental impact. Offers consistent quality without seasonal variation.

Explore 2,3,4,4a,5,6,7,8-Octahydro-2,5,5-trimethyl-2-naphtol

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References

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

    Report a data error

    Ingredient Data Sheet

    CAS 643-53-8

    Physical Properties

    Molecular Weight194.31 g/mol🔬 PubChem
    LogP (Octanol-Water)2.8🔬 PubChem
    Boiling Point266 °C🔬 EPA CompTox
    Vapor Pressure0.0062 mmHg @ 25°C📊 OPERA
    Flash Point115.3 °C🔬 EPA CompTox
    Involatility Index0.0005💻 Calculated
    log Kp (skin permeability)-1.897💻 Calculated
    SMILESCC1(CCCC2=CC(CCC21)(C)O)C🔬 PubChem

    Volatility & Performance

    Fragrance NoteHeart💻 Calculated
    Volatility ClassVery slow💻 Calculated
    Persistence Score4 / 5💻 Calculated

    Odor & Flavor

    Functional Groupsalcoholalkene💻 RDKit
    Data Sources & Attribution
    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: DTXSID30862350

    Physical Properties

    Molecular Weight 194.318 g/mol🔬 EPA CompTox
    Density 0.968 g/cm^3📊 OPERA
    Boiling Point 270.314 °C📊 OPERA
    Melting Point 79.917 °C📊 OPERA
    Flash Point 117.577 °C📊 OPERA
    Refractive Index 1.512 Dimensionless📊 OPERA
    Molar Volume 197.886 cm^3/mol📊 OPERA

    Partition & Solubility

    LogP (Octanol-Water) 3.63 Log10 unitless📊 OPERA
    LogD (pH 5.5) 3.63 Log10 unitless📊 OPERA
    LogD (pH 7.4) 3.63 Log10 unitless📊 OPERA
    LogKoa (Octanol-Air) 8.57 Log10 unitless📊 OPERA
    Water Solubility 0.003 mol/L📊 OPERA
    Henry's Law Constant 0 atm-m3/mole📊 OPERA

    Transport Properties

    Vapor Pressure 0.003 mmHg📊 OPERA
    Viscosity 9.857 cP📊 OPERA
    Surface Tension 33.658 dyn/cm📊 OPERA
    Thermal Conductivity 130.468 mW/(m*K)📊 OPERA

    Molecular Descriptors

    Topological Polar Surface Area 20.23 Ų💻 Computed
    H-Bond Donors 1 count💻 Computed
    H-Bond Acceptors 1 count💻 Computed
    Rotatable Bonds 0 count💻 Computed
    Aromatic Rings 0 count💻 Computed
    Molar Refractivity 59.361 cm^3/mol📊 OPERA
    Polarizability 23.532 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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