.alpha.,.alpha.,6,6-Tetramethylbicyclo[3.1.1]hept-2-ene-2-propionaldehyde (CAS 33885-52-8) — Woody Middle to base Note Fragrance Ingredient
.alpha.,.alpha.,6,6-Tetramethylbicyclo[3.1.1]hept-2-ene-2-propionaldehyde
CAS 33885-52-8
What Is .alpha.,.alpha.,6,6-Tetramethylbicyclo[3.1.1]hept-2-ene-2-propionaldehyde?
α,α,6,6-Tetramethylbicyclo[3.1.1]hept-2-ene-2-propionaldehyde is a synthetic fragrance ingredient used in modern perfumery. It contributes woody, pine-like nuances to fragrances. This molecule is found in niche and designer perfumes aiming for crisp, forest-like accords. Its complex structure allows perfumers to create unique scent profiles that mimic natural aromas while offering superior stability. The ingredient matters because it provides a sustainable alternative to harvesting rare natural materials, and its precise chemical structure enables consistent scent reproduction across batches.
Safety Profile
USE WITH AWARENESSWhat Does .alpha.,.alpha.,6,6-Tetramethylbicyclo[3.1.1]hept-2-ene-2-propionaldehyde Smell Like?
This bicyclic aldehyde opens with a sharp, almost metallic pine needle freshness that quickly settles into a dense forest floor character. Imagine the crisp snap of breaking pine branches layered over damp moss. As it evolves, the scent reveals subtle citrus undertones and a clean woody dryness reminiscent of freshly sanded cedar. The dry-down maintains remarkable tenacity, transforming into an elegant amber-woody base with faint resinous sweetness.
2D Molecular Structure
SMILES: CC(C)(CC1=CCC2CC1C2(C)C)C=O
Chemistry, Properties & Perfumer Guide
The Chemistry
This bicyclic terpenoid aldehyde belongs to the pinane structural family, characterized by its rigid bicyclo[3.1.1]heptane framework. The molecule features two quaternary carbons and an aldehyde group positioned alpha to the bridgehead carbon. Industrial synthesis typically involves Diels-Alder reactions of myrcene derivatives followed by selective oxidation. The tetramethyl substitution pattern creates significant steric hindrance, influencing both its odor profile and chemical reactivity. The aldehyde functionality is relatively stable due to protection by the bulky hydrocarbon framework.
Physical & Chemical Properties
| Molecular Class | Bicyclic terpenoid aldehyde |
|---|---|
| Complexity | 247 (calculated) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Woody accord enhancer |
| Functional Fragrance | 0.1-0.5% | Up to 1% | Pine-type cleaner scents |
Classic Accords
Tip: Use with citrus top notes to brighten the woody character and prevent excessive heaviness.
Alternatives & Comparisons
Similar woody character but with more pronounced citrus aspects and better diffusion.
Provides comparable woody-amber dry-down with enhanced muskiness and better stability.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted under IFRA standards. General aldehyde precautions apply.
RIFM Assessment
No specific RIFM evaluation published. General aldehyde safety protocols recommended.
Sustainability
As a synthetic material, this ingredient reduces pressure on natural pine forest resources. Its production avoids the variability and ecological impact of harvesting natural terpenes. Modern synthesis routes aim for atom economy and reduced solvent waste. The material’s potency allows for lower usage rates compared to some natural alternatives.
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Ingredient Data Sheet
CAS 33885-52-8Physical Properties
| Molecular Weight | 206.32 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3.1🔬 PubChem |
| Boiling Point | 259.8 °C🔬 EPA CompTox |
| Vapor Pressure | 0.0255 mmHg @ 25°C📊 OPERA |
| Flash Point | 104 °C🔬 EPA CompTox |
| Involatility Index | 0.0019💻 Calculated |
| log Kp (skin permeability) | -1.758💻 Calculated |
| SMILES | CC1(C2CC=C(C1C2)CC(C)(C)C=O)C🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
| Volatility Class | Very slow💻 Calculated |
| Persistence Score | 3.1 / 5💻 Calculated |
Odor & Flavor
| Functional Groups | aldehydealkene💻 RDKit |
Regulatory Status
| IFRA Listed | Yes — see IFRA Standards for category limits⚖️ IFRA 51 |
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: DTXSID5051490
Physical Properties
| Molecular Weight | 206.329 g/mol🔬 EPA CompTox |
| Density | 0.941 g/cm^3🔬 EPA CTX |
| Boiling Point | 259.8 °C🔬 EPA CTX |
| Melting Point | 38.397 °C📊 OPERA |
| Flash Point | 104 °C🔬 EPA CTX |
| Refractive Index | 1.483 Dimensionless📊 OPERA |
| Molar Volume | 219.372 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 5.4 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 4.355 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 4.355 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 6.7 Log10 unitless📊 OPERA |
| Water Solubility | 0 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.026 mmHg🔬 EPA CTX |
| Surface Tension | 29.749 dyn/cm📊 OPERA |
| Thermal Conductivity | 114.72 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 | 3 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 62.633 cm^3/mol📊 OPERA |
| Polarizability | 24.83 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.
