2,2,3-Trimethyl-3-Cyclopentene-1-acetaldehyde (CAS 4501-58-0) — Woody Middle Note Fragrance Ingredient
2,2,3-Trimethyl-3-Cyclopentene-1-acetaldehyde
CAS 4501-58-0
What Is 2,2,3-Trimethyl-3-Cyclopentene-1-acetaldehyde?
2,2,3-Trimethyl-3-Cyclopentene-1-acetaldehyde is a synthetic fragrance ingredient used in modern perfumery. It’s found in niche and designer fragrances, often as a fresh, woody modifier. This aldehyde contributes to contemporary scent profiles by adding crispness and diffusion. Its structural complexity allows perfumers to create novel olfactory effects that bridge natural and synthetic accords.
Safety Profile
GENERALLY SAFEWhat Does 2,2,3-Trimethyl-3-Cyclopentene-1-acetaldehyde Smell Like?
This synthetic aldehyde presents a multifaceted aroma profile. Initially sharp and metallic, like crushed aluminum foil against citrus zest, it evolves into a damp forest floor character with hints of ambergris. The dry-down reveals a whisper of violet leaf and a cooling, almost mentholated effect. Its tenacity is moderate but impactful, serving as an olfactory ‘highlighter’ that amplifies adjacent notes without dominating.
2D Molecular Structure
SMILES: CC1=CC[C@H](CC=O)C1(C)C
Chemistry, Properties & Perfumer Guide
The Chemistry
2,2,3-Trimethyl-3-Cyclopentene-1-acetaldehyde belongs to the cyclopentene derivative class of fragrance aldehydes. Its synthesis typically involves Diels-Alder reactions with appropriate dienes and dienophiles, followed by oxidation steps. The molecule’s constrained cyclopentene ring creates steric hindrance that influences both volatility and odor characteristics. While not found in nature, its structure mimics certain terpenoid degradation products.
Physical & Chemical Properties
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Used as diffusive modifier |
| Functional Fragrance | 0.1-0.5% | Up to 1% | Boosts freshness |
Classic Accords
Tip: Use in trace amounts to add lift to woody ambers.
Alternatives & Comparisons
More floral and less metallic, better for mainstream applications where smoothness is preferred.
Softer floral character with similar diffusion properties but greater stability in soap bases.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No current IFRA restrictions. Not listed in any amendment as of 2023.
RIFM Assessment
Not currently evaluated by RIFM. Limited toxicological data available.
Sustainability
As a synthetic material, this ingredient doesn’t rely on agricultural resources. Production involves petrochemical feedstocks, but its high potency means minimal quantities are required in formulations. The synthesis route has not been evaluated for green chemistry metrics.
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Ingredient Data Sheet
CAS 4501-58-0Physical Properties
| Molecular Weight | 152.23 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 1.9🔬 PubChem |
| Boiling Point | 217 °C🔬 EPA CompTox |
| Vapor Pressure | 0.15 mmHg @ 25°C📊 OPERA |
| Flash Point | 76 °C🔬 EPA CompTox |
| Involatility Index | 0.0131💻 Calculated |
| log Kp (skin permeability) | -2.28💻 Calculated |
| SMILES | CC1=CCC(C1(C)C)CC=O🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
| Volatility Class | Slow💻 Calculated |
| Persistence Score | 1.2 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | greenwoody• leffingwell |
| Functional Groups | aldehydealkene💻 RDKit |
| “a great variety of fragrance types, other than This material is listed under its trade name Violet and leaf-types. because it was known for some time under Its main asset is its natural sweet-weedy that name and not under the inconvenient odor, which falls equally well into a Violet chemical name, only recently revealed.”📖 Arctander | |
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: DTXSID3044756
Physical Properties
| Molecular Weight | 152.237 g/mol🔬 EPA CompTox |
| Density | 0.921 g/cm^3🔬 EPA CTX |
| Boiling Point | 217.425 °C🔬 EPA CTX |
| Melting Point | 17.586 °C📊 OPERA |
| Flash Point | 76 °C🔬 EPA CTX |
| Refractive Index | 1.446 Dimensionless📊 OPERA |
| Molar Volume | 173.298 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 2.839 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 2.839 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 2.839 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.84 Log10 unitless📊 OPERA |
| Water Solubility | 0.004 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.15 mmHg🔬 EPA CTX |
| Viscosity | 1.374 cP📊 OPERA |
| Surface Tension | 25.122 dyn/cm📊 OPERA |
| Thermal Conductivity | 125.283 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 | 2 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 46.201 cm^3/mol📊 OPERA |
| Polarizability | 18.316 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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