2,5-Octadien-4-one, 5,6,7-trimethyl-, (2E,5Z)- (CAS 357650-26-1) — Green Top to Heart Note Fragrance Ingredient

ByThe Good Scents
Green · Sweet

2,5-Octadien-4-one, 5,6,7-trimethyl-, (2E,5Z)-

CAS 357650-26-1

Origin
synthetic
Note
Top to Heart
IFRA
Use with awareness
Data as of: Apr 2026

What Is 2,5-Octadien-4-one, 5,6,7-trimethyl-, (2E,5Z)-?

2,5-Octadien-4-one, 5,6,7-trimethyl-, (2E,5Z)- is a synthetic fragrance molecule used in fine perfumery to create unique olfactory effects. It is typically found in niche or experimental fragrances. This ingredient matters because it offers perfumers a tool to craft novel scent profiles that stand out in competitive markets.

Safety Profile

USE WITH AWARENESS
Generally safeUse with awarenessProfessional use
⚠ Limited safety data available
⚠ Use in professional formulations only
CAS
357650-26-1
Formula
Mixture
MW
Variable
Odor Family
Green · Sweet
Layer 1 · Enthusiast

What Does 2,5-Octadien-4-one, 5,6,7-trimethyl-, (2E,5Z)- Smell Like?

This synthetic molecule delivers a complex olfactory profile, often described as a blend of fruity, green, and slightly woody nuances. Its top note is sharp and slightly metallic, evolving into a heart with fruity undertones reminiscent of unripe berries. The dry-down reveals a subtle woody character, making it versatile for modern fragrance compositions.

Scent Profile
Layer 2

2D Molecular Structure

(2E,5Z)-5,6,7-Trimethyl-2,5-octadien-4-one

SMILES: C\C=C\C(=O)C(\C)=C(\C)C(C)C

Chemistry, Properties & Perfumer Guide

The Chemistry

2,5-Octadien-4-one, 5,6,7-trimethyl-, (2E,5Z)- is a synthetic ketone with a complex double-bond structure. It is not found in nature and is typically synthesized through controlled organic reactions. The molecule’s stereochemistry (2E,5Z) plays a crucial role in its olfactory properties, influencing both its volatility and scent profile.

Physical & Chemical Properties

Boiling PointN/A
DensityN/A

Perfumer Guide

Note Position
Top to Heart
Volatility
Medium (1-2 hours)
Blending
Good
ApplicationTypical %RangeNotes
Fine Fragrance0.1-1%Up to 2%Used as a modifier for fruity-green accords

Classic Accords

Tip: Use sparingly to avoid overpowering other notes.

Alternatives & Comparisons

1
Damascenone CAS 23726-93-4

Offers similar fruity-woody characteristics with more established safety data.

Layer 3

Safety, Regulatory & Sustainability

⚠ Regulatory Disclaimer

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

IFRA Status

No specific IFRA restrictions currently apply.

RIFM Assessment

No RIFM assessment available.

Sustainability

As a synthetic molecule, its environmental impact depends on production methods. Being lab-created, it doesn’t deplete natural resources but requires energy-intensive processes.

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References

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

    Report a data error

    Ingredient Data Sheet

    CAS 357650-26-1

    Physical Properties

    Molecular Weight166.26 g/mol🔬 PubChem
    LogP (Octanol-Water)3.4🔬 PubChem
    Boiling Point226 °C🔬 EPA CompTox
    Vapor Pressure0.631 mmHg @ 25°C📊 OPERA
    Flash Point89.4 °C🔬 EPA CompTox
    Involatility Index0.0527💻 Calculated
    log Kp (skin permeability)-1.3💻 Calculated
    SMILESCC=CC(=O)C(=C(C)C(C)C)C🔬 PubChem

    Volatility & Performance

    Fragrance NoteHeart💻 Calculated
    Volatility ClassSlow💻 Calculated
    Persistence Score0.5 / 5💻 Calculated

    Odor & Flavor

    Primary Descriptorsgreensweet• leffingwell
    Functional Groupsketonealkene💻 RDKit

    Regulatory Status

    IFRA ListedYes — see IFRA Standards for category limits⚖️ IFRA 51
    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: DTXSID00889170

    Physical Properties

    Molecular Weight 166.264 g/mol🔬 EPA CompTox
    Density 0.875 g/cm^3📊 OPERA
    Boiling Point 226.056 °C📊 OPERA
    Melting Point 20.915 °C📊 OPERA
    Flash Point 85.577 °C📊 OPERA
    Refractive Index 1.455 Dimensionless📊 OPERA
    Molar Volume 194.438 cm^3/mol📊 OPERA

    Partition & Solubility

    LogP (Octanol-Water) 3.451 Log10 unitless📊 OPERA
    LogD (pH 5.5) 3.451 Log10 unitless📊 OPERA
    LogD (pH 7.4) 3.451 Log10 unitless📊 OPERA
    LogKoa (Octanol-Air) 5.22 Log10 unitless📊 OPERA
    Water Solubility 0.002 mol/L📊 OPERA
    Henry's Law Constant 0 atm-m3/mole📊 OPERA

    Transport Properties

    Vapor Pressure 0.299 mmHg📊 OPERA
    Surface Tension 28.102 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 3 count💻 Computed
    Aromatic Rings 0 count💻 Computed
    Molar Refractivity 52.8 cm^3/mol📊 OPERA
    Polarizability 20.931 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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