5(Or 6)-Methyl-7(or 8)-(1-methylethyl)bicyclo[2.2.2]oct-5-ene-2-carbaldehyde (CAS 68259-31-4) — Woody Middle Note Fragrance Ingredient

Woody · Green

5(Or 6)-Methyl-7(or 8)-(1-methylethyl)bicyclo[2.2.2]oct-5-ene-2-carbaldehyde

CAS 68259-31-4

Origin
synthetic
Note
Middle
IFRA
Professional use
Data as of: Apr 2026

What Is 5(Or 6)-Methyl-7(or 8)-(1-methylethyl)bicyclo[2.2.2]oct-5-ene-2-carbaldehyde?

This synthetic fragrance compound is a complex bicyclic aldehyde primarily used by professional perfumers. Consumers might encounter it in niche or avant-garde fragrances where unusual woody-green notes are desired. Its intricate structure creates a unique olfactory signature that’s hard to replicate with natural materials, making it valuable for creating distinctive modern accords.

Safety Profile

PROFESSIONAL USE
Generally safeUse with awarenessProfessional use
Limited safety data available
Potential skin sensitizer
CAS
68259-31-4
Formula
Mixture
MW
Variable
Odor Family
Woody · Green
Layer 1 · Enthusiast

What Does 5(Or 6)-Methyl-7(or 8)-(1-methylethyl)bicyclo[2.2.2]oct-5-ene-2-carbaldehyde Smell Like?

This bicyclic aldehyde presents an intriguing duality – opening with a sharp, almost metallic greenness reminiscent of crushed stems, then unfolding into a damp woody character with hints of mushroom earthiness. The dry-down reveals subtle camphoraceous undertones and a lingering dry cedar-like persistence. Its complex structure creates an evolving scent profile that bridges the gap between herbal freshness and deep forest notes.

Scent Profile
Layer 2

2D Molecular Structure

5(or 6)-Methyl-7(or 8)-(1-methylethyl)bicyclo[2.2.2]oct-5-ene-2-carbaldehyde

SMILES: CC(C)C1CC2CC(C=O)C1C=C2C

Chemistry, Properties & Perfumer Guide

The Chemistry

This bicyclic terpene aldehyde belongs to a class of structurally complex synthetic fragrance materials designed to mimic natural woody-green notes. The molecule features a strained bicyclo[2.2.2]octene core with aldehyde and isopropyl substituents that create significant steric hindrance. Synthesis typically involves Diels-Alder cycloaddition followed by oxidative transformations. The multiple possible substitution patterns (5/6 and 7/8 positions) often result in isomeric mixtures that contribute to its complex olfactory profile.

Physical & Chemical Properties

Perfumer Guide

Note Position
Middle
Volatility
Medium (2-6 hours)
Blending
Moderate
ApplicationTypical %RangeNotes
Fine Fragrance0.1-0.5%Up to 1%Used as woody-green modifier
Functional Fragrance0.01-0.1%Up to 0.3%Limited use due to potency

Classic Accords

Tip: Use sparingly in woody bases to add structural complexity without overwhelming the composition.

Alternatives & Comparisons

1
Verdox CAS 88-41-5

A more stable and widely used synthetic green-woody note with better safety profile for mainstream applications.

2
Dihydroambrinol CAS 67999-59-9

For similar woody persistence but with ambered rather than green tonalities.

Layer 3

Safety, Regulatory & Sustainability

⚠ Regulatory Disclaimer

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

IFRA Status

Not currently restricted by IFRA, but usage should be monitored due to limited safety data.

GHS Classification

H315 Skin irritation H317 May cause allergic skin reaction

RIFM Assessment

No RIFM assessment currently available for this specific compound.

Sustainability

As a purely synthetic material, this compound avoids natural resource depletion but requires energy-intensive synthesis. Its complex structure may present challenges for biodegradation. Perfumers should consider its relatively high potency – small quantities can achieve significant effects, potentially reducing overall environmental load compared to less potent alternatives.

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References

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

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    Physicochemical Properties

    DTXSID: DTXSID6052405

    Physical Properties

    Molecular Weight 192.302 g/mol🔬 EPA CompTox
    Density 0.965 g/cm^3📊 OPERA
    Boiling Point 258.564 °C📊 OPERA
    Melting Point 19.752 °C📊 OPERA
    Flash Point 95.846 °C📊 OPERA
    Refractive Index 1.531 Dimensionless📊 OPERA
    Molar Volume 192.915 cm^3/mol📊 OPERA

    Partition & Solubility

    LogP (Octanol-Water) 3.747 Log10 unitless📊 OPERA
    LogD (pH 5.5) 3.747 Log10 unitless📊 OPERA
    LogD (pH 7.4) 3.747 Log10 unitless📊 OPERA
    LogKoa (Octanol-Air) 6.09 Log10 unitless📊 OPERA
    Water Solubility 0 mol/L📊 OPERA
    Henry's Law Constant 0 atm-m3/mole📊 OPERA

    Transport Properties

    Vapor Pressure 0.017 mmHg📊 OPERA
    Viscosity 9.695 cP📊 OPERA
    Surface Tension 32.751 dyn/cm📊 OPERA
    Thermal Conductivity 125.664 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 2 count💻 Computed
    Aromatic Rings 0 count💻 Computed
    Molar Refractivity 59.728 cm^3/mol📊 OPERA
    Polarizability 23.678 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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