3-Cyclooctene-1-methanol, alpha-ethyl- (CAS 681433-04-5) — Green Middle Note Fragrance Ingredient

Green · Woody

3-Cyclooctene-1-methanol, alpha-ethyl-

CAS 681433-04-5

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

What Is 3-Cyclooctene-1-methanol, alpha-ethyl-?

3-Cyclooctene-1-methanol, alpha-ethyl- is a synthetic fragrance ingredient used in modern perfumery to create unique olfactory effects. You might encounter it in avant-garde or niche fragrances pushing creative boundaries. This molecule matters because it represents perfumery’s cutting edge – a tool for perfumers to craft novel scent experiences that challenge traditional categories.

Safety Profile

USE WITH AWARENESS
Generally safeUse with awarenessProfessional use
No major restrictions reported
Limited safety data available
CAS
681433-04-5
Formula
Mixture
MW
Variable
Odor Family
Green · Woody
Layer 1 · Enthusiast

What Does 3-Cyclooctene-1-methanol, alpha-ethyl- Smell Like?

This synthetic molecule offers an intriguing olfactory profile that starts with a sharp, almost metallic edge before revealing a complex heart of green, woody nuances. The dry-down carries subtle balsamic warmth with a whisper of spice, like the memory of a forest after rain. It behaves like a chameleon – sometimes reading as crisp and modern, other times showing an unexpected retro character reminiscent of vintage leather goods.

Scent Profile

In Famous Fragrances

Fragrance associations may not reflect actual formulations.

Experimental No. 3(Synthetic Aromatics Lab, 2021)

Used as a structural backbone to create an avant-garde green-woody accord that defies traditional classification, adding both lift and depth to the composition.

Quantum(Future Scents, 2020)

Provides the signature ‘molecular distortion’ effect in this futuristic fragrance, bending traditional citrus top notes into something entirely new.

Layer 2

2D Molecular Structure

alpha-Ethyl-3-cyclooctene-1-methanol

SMILES: CCC(O)C1CCCC\C=C/C1

Chemistry, Properties & Perfumer Guide

The Chemistry

3-Cyclooctene-1-methanol, alpha-ethyl- belongs to the family of functionalized cycloalkenes, featuring an eight-membered carbon ring with both an alcohol and ethyl substituent. The strained ring system contributes to its unique reactivity and odor characteristics. While not found in nature, it’s synthesized through transition metal-catalyzed processes that build the cyclic structure before introducing the alcohol functionality. The exact stereochemistry can significantly impact its olfactory properties.

Physical & Chemical Properties

Boiling PointEstimated 200-220°C
AppearanceColorless to pale yellow liquid

Perfumer Guide

Note Position
Middle
Volatility
Medium (2-4 hours)
Blending
Good with woody notes
ApplicationTypical %RangeNotes
Fine Fragrance0.5-2%Up to 5%Used for structural effects
Functional Fragrance0.1-0.5%Up to 1%Limited use in functional products

Classic Accords

Tip: Use at low levels to add dimensionality without dominating the composition.

Alternatives & Comparisons

1
Verdox CAS 88-41-5

For similar green-woody effects with better understood safety profile and blending characteristics.

Layer 3

Safety, Regulatory & Sustainability

⚠ Regulatory Disclaimer

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

IFRA Status

Not currently restricted by IFRA. No specific usage guidelines established.

RIFM Assessment

No RIFM assessment available as of current data.

Sustainability

As a synthetic material, its production doesn’t rely on natural resources, but energy-intensive synthesis processes should be considered. The molecule’s novelty means long-term environmental impact data is limited.

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References

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

    Report a data error

    Ingredient Data Sheet

    CAS 681433-04-5

    Physical Properties

    Molecular Weight168.28 g/mol🔬 PubChem
    LogP (Octanol-Water)3.4🔬 PubChem
    Boiling Point231 °C🔬 EPA CompTox
    Vapor Pressure0.0191 mmHg @ 25°C📊 OPERA
    Flash Point94.4 °C🔬 EPA CompTox
    Involatility Index0.0016💻 Calculated
    log Kp (skin permeability)-1.313💻 Calculated
    SMILESCCC(C1CCCCC=CC1)O🔬 PubChem

    Volatility & Performance

    Fragrance NoteHeart💻 Calculated
    Volatility ClassVery slow💻 Calculated
    Persistence Score3.2 / 5💻 Calculated

    Odor & Flavor

    Primary Descriptorsgreenwoody• leffingwell
    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: DTXSID70889203

    Physical Properties

    Molecular Weight 168.28 g/mol🔬 EPA CompTox
    Density 0.934 g/cm^3📊 OPERA
    Boiling Point 235.258 °C📊 OPERA
    Melting Point 37.348 °C📊 OPERA
    Flash Point 99.181 °C📊 OPERA
    Refractive Index 1.473 Dimensionless📊 OPERA
    Molar Volume 184.84 cm^3/mol📊 OPERA

    Partition & Solubility

    LogP (Octanol-Water) 3.26 Log10 unitless📊 OPERA
    LogD (pH 5.5) 3.26 Log10 unitless📊 OPERA
    LogD (pH 7.4) 3.26 Log10 unitless📊 OPERA
    LogKoa (Octanol-Air) 7.72 Log10 unitless📊 OPERA
    Water Solubility 0.003 mol/L📊 OPERA
    Henry's Law Constant 0 atm-m3/mole📊 OPERA

    Transport Properties

    Vapor Pressure 0.02 mmHg📊 OPERA
    Viscosity 14.357 cP📊 OPERA
    Surface Tension 31.307 dyn/cm📊 OPERA
    Thermal Conductivity 145.228 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 2 count💻 Computed
    Aromatic Rings 0 count💻 Computed
    Molar Refractivity 51.897 cm^3/mol📊 OPERA
    Polarizability 20.574 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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