4-(2,6,6-Trimethyl-2-cyclohexen)-2-methylbutanal (CAS 65405-84-7) — Woody Heart to Base Note Fragrance Ingredient
4-(2,6,6-Trimethyl-2-cyclohexen)-2-methylbutanal
CAS 65405-84-7
What Is 4-(2,6,6-Trimethyl-2-cyclohexen)-2-methylbutanal?
4-(2,6,6-Trimethyl-2-cyclohexen)-2-methylbutanal is a synthetic fragrance ingredient used to add woody, floral, and slightly fruity nuances to perfumes. It’s found in various fine fragrances and personal care products. This molecule helps create sophisticated, long-lasting scent profiles, often contributing to the heart or base notes of a fragrance. Its balanced character makes it valuable for perfumers seeking to bridge floral and woody accords.
Safety Profile
USE WITH AWARENESSWhat Does 4-(2,6,6-Trimethyl-2-cyclohexen)-2-methylbutanal Smell Like?
This aldehyde opens with a crisp, slightly green floralcy reminiscent of crushed leaves and fresh petals. As it evolves, it reveals a sophisticated woody-amber character with subtle fruity undertones—like ripe plums wrapped in sandalwood. The dry-down is warm and persistent, with a velvety texture that blends seamlessly with musks and vanillic notes. Its behavior is reminiscent of more expensive natural materials, making it a perfumer’s secret weapon for adding depth without heaviness.
2D Molecular Structure
SMILES: CC(CCC1C(C)CCCC1(C)C)C=O
Chemistry, Properties & Perfumer Guide
The Chemistry
4-(2,6,6-Trimethyl-2-cyclohexen)-2-methylbutanal belongs to the family of cyclic terpene aldehydes. While not found in nature, it’s structurally related to ionones and damascones. Synthesis typically involves the condensation of trimethylcyclohexene derivatives with methylbutanal precursors. The molecule’s stereochemistry significantly impacts its odor profile, with different isomers exhibiting varying intensities of floral versus woody character. Its aldehyde group contributes to both reactivity and diffusion properties in formulations.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Odor Threshold | Low (high potency) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Adds woody-floral complexity |
| Personal Care | 0.1-0.5% | Up to 1% | Used for substantivity |
Classic Accords
Tip: Use with ionones to enhance floralcy or with woody ambers to boost diffusion.
Alternatives & Comparisons
Offers similar woody-floral character but with less fruity nuance and better stability in alkaline formulations.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted under IFRA standards. Monitoring status as of 2022.
RIFM Assessment
Under review by RIFM for comprehensive safety assessment (2023 update pending).
Sustainability
As a synthetic material, this ingredient avoids natural resource depletion but requires petrochemical feedstocks. Modern production methods aim to optimize atom economy and reduce waste. Its high potency means minimal quantities are needed in formulations, reducing overall environmental load compared to less powerful alternatives.
Explore 4-(2,6,6-Trimethyl-2-cyclohexen)-2-methylbutanal
Browse essential oils and aroma compounds.
Browse on iHerb →Affiliate disclosure: we may earn a small commission at no extra cost to you.
References
- Brenna et al. (2012). Synthetic routes to cyclic terpene aldehydes. Flavour and Fragrance Journal.
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID5052339
Physical Properties
| Molecular Weight | 210.361 g/mol🔬 EPA CompTox |
| Density | 0.846 g/cm^3📊 OPERA |
| Boiling Point | 261.052 °C📊 OPERA |
| Melting Point | 22.451 °C📊 OPERA |
| Flash Point | 116.321 °C📊 OPERA |
| Refractive Index | 1.434 Dimensionless📊 OPERA |
| Molar Volume | 249.647 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 4.838 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 4.838 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 4.838 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 6.56 Log10 unitless📊 OPERA |
| Water Solubility | 0 mol/L📊 OPERA |
| Henry's Law Constant | 0.001 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.01 mmHg📊 OPERA |
| Viscosity | 3.106 cP📊 OPERA |
| Surface Tension | 27.947 dyn/cm📊 OPERA |
| Thermal Conductivity | 125.412 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 | 4 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 65.071 cm^3/mol📊 OPERA |
| Polarizability | 25.796 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.
