Trimethyl-bicyclo-heptane-spirocyclohexenone (CAS 133636-82-5) — Woody Middle to base Note Fragrance Ingredient

Woody · Balsamic

Trimethyl-bicyclo-heptane-spirocyclohexenone

CAS 133636-82-5

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

What Is Trimethyl-bicyclo-heptane-spirocyclohexenone?

Trimethyl-bicyclo-heptane-spirocyclohexenone is a synthetic fragrance ingredient used in modern perfumery. It’s typically found in niche and avant-garde fragrances where unique, abstract scents are desired. This compound matters because it represents the cutting edge of fragrance chemistry, allowing perfumers to create novel olfactory experiences that don’t exist in nature.

Safety Profile

USE WITH AWARENESS
Generally safeUse with awarenessProfessional use
Approved for use in fragrances
Limited safety data available
CAS
133636-82-5
Formula
Mixture
MW
Variable
Odor Family
Woody · Balsamic
Layer 1 · Enthusiast

What Does Trimethyl-bicyclo-heptane-spirocyclohexenone Smell Like?

Trimethyl-bicyclo-heptane-spirocyclohexenone presents a complex, abstract aroma that defies simple classification. It opens with a sharp, metallic edge reminiscent of cold steel, evolving into a warm, woody-ambery heart with subtle spicy undertones. The dry-down reveals a lingering mineralic quality, like sun-warmed stones, with a faint camphoraceous whisper. Its odor profile is highly synthetic yet intriguing, creating an otherworldly effect that works well in conceptual fragrances.

Scent Profile
Layer 2

2D Molecular Structure

(1S,2S,3S,5R)-2,6,6-Trimethylspiro[bicyclo[3.1.1]heptane-3,1'-cyclohexane]-2'-en-4'-one

SMILES: C[C@H]1[C@@H]2C[C@H](C[C@]11CCC(=O)C=C1)C2(C)C

Chemistry, Properties & Perfumer Guide

The Chemistry

Trimethyl-bicyclo-heptane-spirocyclohexenone is a synthetic bicyclic ketone with a complex spirocyclic structure. Its molecular architecture combines rigid cyclohexenone and bicycloheptane frameworks, creating unique steric and electronic properties that influence its odor characteristics. Synthesis typically involves multi-step organic transformations including cyclization and oxidation reactions. The three methyl groups contribute to its volatility and modify its interaction with olfactory receptors.

Physical & Chemical Properties

Perfumer Guide

Note Position
Middle to base
Volatility
Medium (2-6 hours)
Blending
Moderate
ApplicationTypical %RangeNotes
Fine Fragrance0.5-2%Up to 5%Used as an abstract modifier
Functional Fragrance0.1-0.5%Up to 1%For industrial applications

Classic Accords

Tip: Use sparingly to add an unconventional edge to woody-ambery bases.

Alternatives & Comparisons

1
Iso E Super CAS 54464-57-2

A more conventional woody-amber with better safety data and blending properties.

2
Ambroxan CAS 6790-58-5

Provides similar longevity but with a more natural ambergris character.

Layer 3

Safety, Regulatory & Sustainability

⚠ Regulatory Disclaimer

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

IFRA Status

Not currently restricted by IFRA.

RIFM Assessment

No RIFM assessment currently available.

Sustainability

As a synthetic material, this compound is produced through controlled chemical processes with minimal environmental impact compared to some natural materials. However, its complex synthesis may require multiple steps with associated energy inputs. The long-term biodegradability profile is not well characterized.

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References

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

    Report a data error

    Ingredient Data Sheet

    CAS 133636-82-5

    Physical Properties

    Molecular Weight218.33 g/mol🔬 PubChem
    LogP (Octanol-Water)3.8🔬 PubChem
    Boiling Point292 °C🔬 EPA CompTox
    Vapor Pressure0.0023 mmHg @ 25°C📊 OPERA
    Flash Point159.9 °C🔬 EPA CompTox
    Involatility Index0.0002💻 Calculated
    log Kp (skin permeability)-1.334💻 Calculated
    SMILESCC1C2CC(C2(C)C)CC13CCC(=O)C=C3🔬 PubChem

    Volatility & Performance

    Fragrance NoteBase💻 Calculated
    Volatility ClassVery slow💻 Calculated
    Persistence Score5.6 / 5💻 Calculated

    Odor & Flavor

    Primary Descriptorsbalsamicwoody• leffingwell
    Functional Groupsketonealkene💻 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: DTXSID1051480

    Physical Properties

    Molecular Weight 218.34 g/mol🔬 EPA CompTox
    Density 1.011 g/cm^3📊 OPERA
    Boiling Point 300.635 °C📊 OPERA
    Melting Point 68.015 °C📊 OPERA
    Flash Point 142.505 °C📊 OPERA
    Refractive Index 1.526 Dimensionless📊 OPERA
    Molar Volume 212.727 cm^3/mol📊 OPERA

    Partition & Solubility

    LogP (Octanol-Water) 4.372 Log10 unitless📊 OPERA
    LogD (pH 5.5) 4.372 Log10 unitless📊 OPERA
    LogD (pH 7.4) 4.372 Log10 unitless📊 OPERA
    LogKoa (Octanol-Air) 7.32 Log10 unitless📊 OPERA
    Water Solubility 0 mol/L📊 OPERA
    Henry's Law Constant 0 atm-m3/mole📊 OPERA

    Transport Properties

    Vapor Pressure 0.001 mmHg📊 OPERA
    Surface Tension 34.839 dyn/cm📊 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 65.345 cm^3/mol📊 OPERA
    Polarizability 25.905 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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