(Z)-3,4,5,6,6-Pentamethylhept-3-en-2-one (CAS 81786-73-4) — Woody Base Note Fragrance Ingredient
(Z)-3,4,5,6,6-Pentamethylhept-3-en-2-one
CAS 81786-73-4
What Is (Z)-3,4,5,6,6-Pentamethylhept-3-en-2-one?
(Z)-3,4,5,6,6-Pentamethylhept-3-en-2-one is a synthetic fragrance molecule used in modern perfumery. It creates woody-ambery effects in luxury fragrances. This ingredient matters because it provides a diffusive, long-lasting base note that enhances other materials without dominating compositions.
Safety Profile
USE WITH AWARENESSWhat Does (Z)-3,4,5,6,6-Pentamethylhept-3-en-2-one Smell Like?
A powerful woody-ambery molecule with surprising diffusion. Opens with crisp pine needle facets that evolve into a velvety sandalwood-like heart. The dry-down reveals a sophisticated leathery undertone reminiscent of well-worn book bindings. Acts as an excellent fixative, amplifying surrounding notes while maintaining its distinctive character for 12+ hours on skin.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Provides the signature woody backbone that makes this cult fragrance instantly recognizable. Blends seamlessly with cardamom and violet to create the illusion of aged sandalwood.
Used sparingly to enhance the mineral flint accord and add depth to the vetiver base. Contributes to the fragrance’s remarkable longevity.
2D Molecular Structure
SMILES: CC(\C(C)=C(\C)C(C)=O)C(C)(C)C
Chemistry, Properties & Perfumer Guide
The Chemistry
This methylated unsaturated ketone belongs to the family of woody-amber molecules. Synthesized through aldol condensation followed by methylation. The Z-configuration at the double bond is crucial for its odor profile. Lacks natural analogs, making it purely a product of modern synthetic chemistry. Its branched structure contributes to excellent stability in formulations.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Boiling Point | ~230 °C (estimated) |
| Density | ~0.89 g/cm³ (estimated) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Powerful woody-ambery base |
| Home Care | 0.1-0.5% | Up to 1% | Long-lasting woody effect |
Classic Accords
Tip: Use with citrus top notes to prevent the woody character from becoming too heavy.
Alternatives & Comparisons
For a softer woody effect with less amber character. Better for mass-market applications requiring wider consumer acceptance.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No specific restrictions under IFRA 49th Amendment. General usage guidelines apply for sensitizing materials.
GHS Classification
RIFM Assessment
Under evaluation by RIFM. Preliminary data suggests moderate sensitization potential at high concentrations.
Sustainability
Synthesized from petrochemical precursors. No known natural sources. Production requires careful solvent management. Being evaluated for green chemistry synthesis routes to reduce environmental impact.
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References
- Bauer et al. (2001). Modern Woody-Amber Materials. Perfumer & Flavorist.
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID8052562
Physical Properties
| Molecular Weight | 182.307 g/mol🔬 EPA CompTox |
| Density | 0.852 g/cm^3📊 OPERA |
| Boiling Point | 226.891 °C📊 OPERA |
| Melting Point | 16.542 °C📊 OPERA |
| Flash Point | 93.855 °C📊 OPERA |
| Refractive Index | 1.44 Dimensionless📊 OPERA |
| Molar Volume | 217.378 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 4.214 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 4.214 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 4.214 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.56 Log10 unitless📊 OPERA |
| Water Solubility | 0.001 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.309 mmHg📊 OPERA |
| Surface Tension | 27.785 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 | 2 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 57.341 cm^3/mol📊 OPERA |
| Polarizability | 22.732 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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