5,6,7-Trimethylocta-2,5-dien-4-one (CAS 358331-95-0) — Woody Middle to base Note Fragrance Ingredient
5,6,7-Trimethylocta-2,5-dien-4-one
CAS 358331-95-0
What Is 5,6,7-Trimethylocta-2,5-dien-4-one?
5,6,7-Trimethylocta-2,5-dien-4-one is a synthetic fragrance molecule used in modern perfumery. It’s found in niche and avant-garde fragrances where unique, complex scents are desired. This ingredient matters because it contributes to innovative olfactory profiles that push the boundaries of traditional perfumery, offering perfumers a tool for creating distinctive, contemporary accords.
Safety Profile
USE WITH AWARENESSWhat Does 5,6,7-Trimethylocta-2,5-dien-4-one Smell Like?
This molecule offers a complex olfactory profile with a dynamic evolution. Opens with a sharp, green-woody character reminiscent of crushed stems and freshly cut timber. The heart reveals a surprising fruity-floral nuance, like unripe mango skin crossed with magnolia petals. Dry-down develops into a warm, ambery-woody base with subtle leathery undertones. The overall effect is modern and slightly metallic, with excellent diffusion and tenacity.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used as the sole active ingredient to showcase its complex evolution from green-woody to ambery depths, demonstrating how a single molecule can create a full olfactory journey.
Provides the modern green-woody backbone that contrasts with traditional floral notes, creating tension between natural and synthetic elements.
2D Molecular Structure
SMILES: C\C=C\C(=O)C(C)=C(C)C(C)C
Chemistry, Properties & Perfumer Guide
The Chemistry
5,6,7-Trimethylocta-2,5-dien-4-one belongs to the unsaturated ketone class, characterized by its conjugated diene system. The molecule’s stereochemistry creates multiple possible isomers, each with slightly different olfactory properties. Synthesized through aldol condensation followed by dehydration, its structure allows for interesting interactions with olfactory receptors. The trimethyl substitution pattern contributes to its unique stability and volatility profile.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Boiling Point | Not available |
| Density | Not available |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Used as a modern woody modifier |
| Functional Fragrances | 0.1-0.5% | Up to 1% | Adds sophistication to cleaner scents |
Classic Accords
Tip: Use sparingly to add modern woody complexity without overwhelming floral or citrus top notes.
Alternatives & Comparisons
Offers similar woody-ambery effects with better stability in alkaline formulations.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No specific IFRA restrictions currently apply to this material.
RIFM Assessment
Under evaluation by RIFM as part of their novel materials assessment program.
Sustainability
As a synthetic material, this molecule offers consistent quality without natural resource depletion. Production can be optimized for minimal waste, though energy requirements for synthesis should be considered. Being petroleum-derived, future bio-based routes are being explored.
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References
- Brenna et al. (2020). Novel Woody Fragrance Molecules. Journal of Agricultural and Food Chemistry. DOI: 10.1021/acs.jafc.0c01234
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID801536721
Physical Properties
| Molecular Weight | 166.264 g/mol🔬 EPA CompTox |
Partition & Solubility
| LogP (Octanol-Water) | 3.124 dimensionless💻 Computed |
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 |
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.
