()-Bicyclo[2.2.1]hept-5-ene-2-carboxylic acid, ethyl ester (CAS 10138-32-6) — Woody Middle Note Fragrance Ingredient
()-Bicyclo[2.2.1]hept-5-ene-2-carboxylic acid, ethyl ester
CAS 10138-32-6
What Is ()-Bicyclo[2.2.1]hept-5-ene-2-carboxylic acid, ethyl ester?
This synthetic ingredient is a specialized fragrance compound rarely encountered by consumers directly. It may appear in niche perfumery or functional fragrances. As a complex ester, it contributes subtle woody-green nuances to fragrance compositions, though it’s primarily used as a building block for more complex aroma chemicals rather than a standalone note.
Safety Profile
USE WITH AWARENESSWhat Does ()-Bicyclo[2.2.1]hept-5-ene-2-carboxylic acid, ethyl ester Smell Like?
The odor profile of this bicyclic ester is characterized by a clean, slightly camphoraceous woody character with subtle green undertones. In dilution, it reveals a faintly fruity-esteric nuance reminiscent of unripe apples. The dry-down tends toward a dry, paper-like woody note with minimal sweetness. When used in trace amounts, it can add diffusion and lift to woody compositions without dominating the fragrance profile.
2D Molecular Structure
SMILES: CCOC(=O)C1CC2CC1C=C2
Chemistry, Properties & Perfumer Guide
The Chemistry
This compound belongs to the class of bicyclic esters derived from norbornene. The bicyclo[2.2.1]heptene skeleton provides structural rigidity that influences both volatility and odor characteristics. While not found in nature, it serves as an intermediate in the synthesis of more complex fragrance ingredients. The ethyl ester group contributes to its moderate volatility and clean esteric character.
Physical & Chemical Properties
| Boiling Point | Not available |
|---|---|
| Density | Not available |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.1-0.5% | Up to 1% | Used as a modifier in woody accords |
| Functional Fragrances | 0.05-0.2% | Up to 0.5% | Provides clean woody notes |
| Household Products | 0.01-0.1% | Up to 0.2% | Adds subtle freshness |
Classic Accords
Tip: Use in trace amounts to add diffusion to woody bases without introducing sweetness.
Alternatives & Comparisons
Offers similar esteric character with more pronounced fruity notes when a stronger top note effect is desired.
Provides comparable woody-camphoraceous effects with better substantivity for longer-lasting fragrances.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No specific IFRA restrictions. General guidelines for ester compounds apply.
RIFM Assessment
Not currently evaluated by RIFM. Safety assessment based on structural analogs.
Sustainability
As a fully synthetic material, this compound avoids natural resource depletion but requires petrochemical feedstocks. Production typically involves catalytic processes with moderate energy requirements. The bicyclic structure offers good stability, potentially reducing fragrance loss and the need for reapplication in end products.
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Ingredient Data Sheet
CAS 10138-32-6Physical Properties
| Molecular Weight | 166.22 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 1.9🔬 PubChem |
| Boiling Point | 231 °C🔬 EPA CompTox |
| Vapor Pressure | 0.0234 mmHg @ 25°C📊 OPERA |
| Flash Point | 75.3 °C🔬 EPA CompTox |
| Involatility Index | 0.002💻 Calculated |
| log Kp (skin permeability) | -2.365💻 Calculated |
| SMILES | CCOC(=O)C1CC2CC1C=C2🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
| Volatility Class | Very slow💻 Calculated |
| Persistence Score | 2.5 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | fruitygreenhoney• leffingwell |
| Functional Groups | esteretheralkene💻 RDKit |
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: DTXSID30884451
Physical Properties
| Molecular Weight | 166.22 g/mol🔬 EPA CompTox |
| Density | 1.089 g/cm^3📊 OPERA |
| Boiling Point | 224.106 °C📊 OPERA |
| Melting Point | 33.806 °C📊 OPERA |
| Flash Point | 86.006 °C📊 OPERA |
| Refractive Index | 1.508 Dimensionless📊 OPERA |
| Molar Volume | 152.625 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 2.845 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 2.845 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 2.845 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.05 Log10 unitless📊 OPERA |
| Water Solubility | 0.013 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.123 mmHg📊 OPERA |
| Viscosity | 4.744 cP📊 OPERA |
| Surface Tension | 34.619 dyn/cm📊 OPERA |
| Thermal Conductivity | 123.212 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 26.3 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 2 count💻 Computed |
| Rotatable Bonds | 2 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 45.522 cm^3/mol📊 OPERA |
| Polarizability | 18.046 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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