Bicyclo[2.2.1]hept-5-ene-2-carboxylic acid, 3-(1-methylethyl)-, ethyl ester, (2-exo,3-endo)- (CAS 116126-82-0) — Woody Middle Note Fragrance Ingredient
Bicyclo[2.2.1]hept-5-ene-2-carboxylic acid, 3-(1-methylethyl)-, ethyl ester, (2-exo,3-endo)-
CAS 116126-82-0
What Is Bicyclo[2.2.1]hept-5-ene-2-carboxylic acid, 3-(1-methylethyl)-, ethyl ester, (2-exo,3-endo)-?
This synthetic fragrance ingredient is a specialized chemical compound used in modern perfumery to create unique olfactory effects. It’s typically found in niche and avant-garde fragrances where unconventional scent profiles are desired. The material offers perfumers a tool for crafting distinctive woody-amber accords with subtle fruity undertones, contributing to contemporary fragrance architectures that push creative boundaries.
Safety Profile
USE WITH AWARENESSWhat Does Bicyclo[2.2.1]hept-5-ene-2-carboxylic acid, 3-(1-methylethyl)-, ethyl ester, (2-exo,3-endo)- Smell Like?
This bicyclic ester presents a complex olfactory profile beginning with crisp, almost metallic top notes reminiscent of crushed green stems. As it evolves, reveals a heart of warm woody character with facets of amber and a faint fruity nuance akin to unripe pear. The dry-down carries subtle musky undertones with excellent tenacity, leaving a clean yet intriguing trail. Its structural rigidity translates to precise scent definition, making it valuable for modern fragrance constructions requiring both projection and longevity.
2D Molecular Structure
SMILES: CCOC(=O)[C@@H]1[C@@H]2C[C@@H](C=C2)[C@H]1C(C)C
Chemistry, Properties & Perfumer Guide
The Chemistry
This bicyclic ester belongs to the class of functionalized norbornane derivatives, characterized by their rigid molecular architecture. The compound is synthesized through Diels-Alder reactions followed by esterification, with the specific stereochemistry (2-exo,3-endo) being crucial for its olfactory properties. The isopropyl group introduces steric effects that influence volatility and scent profile. As a synthetic material, it doesn’t occur in nature but mimics certain aspects of woody-amber natural products while offering superior stability in formulations.
Physical & Chemical Properties
| Molecular Class | Bicyclic ester |
|---|---|
| Structural Features | Rigid norbornane core |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Used as woody-amber modifier |
| Functional Fragrance | 0.1-0.5% | Up to 1% | For technical effects |
Classic Accords
Tip: Use in trace amounts to add structural definition to woody bases without overwhelming other materials.
Alternatives & Comparisons
Provides similar amber-woody effects but with more pronounced diffusion and less fruity nuance.
Offers comparable structural woody character with greater intensity and longer persistence.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted by IFRA. Listed as safe for use at standard concentrations.
RIFM Assessment
Under evaluation by RIFM. Preliminary data suggests safe use at current industry levels.
Sustainability
As a synthetic material, this compound is produced through controlled chemical processes with minimal environmental impact compared to natural alternatives. Its efficient synthesis and high potency reduce the overall carbon footprint in fragrance applications. The material’s stability contributes to longer-lasting fragrances, potentially reducing reapplication frequency.
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Ingredient Data Sheet
CAS 116126-82-0Physical Properties
| Molecular Weight | 208.3 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3.1🔬 PubChem |
| Boiling Point | 243 °C🔬 EPA CompTox |
| Vapor Pressure | 0.0117 mmHg @ 25°C📊 OPERA |
| Flash Point | 104.7 °C🔬 EPA CompTox |
| Involatility Index | 0.0009💻 Calculated |
| log Kp (skin permeability) | -1.77💻 Calculated |
| SMILES | CCOC(=O)C1C2CC(C1C(C)C)C=C2🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
| Volatility Class | Very slow💻 Calculated |
| Persistence Score | 3.7 / 5💻 Calculated |
Odor & Flavor
| Functional Groups | esteretheralkene💻 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: DTXSID0051316
Physical Properties
| Molecular Weight | 208.301 g/mol🔬 EPA CompTox |
| Density | 1.012 g/cm^3📊 OPERA |
| Boiling Point | 248.767 °C📊 OPERA |
| Melting Point | 33.239 °C📊 OPERA |
| Flash Point | 103.931 °C📊 OPERA |
| Refractive Index | 1.492 Dimensionless📊 OPERA |
| Molar Volume | 204.735 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.813 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 3.813 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.813 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 6.08 Log10 unitless📊 OPERA |
| Water Solubility | 0.001 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.011 mmHg📊 OPERA |
| Viscosity | 10.459 cP📊 OPERA |
| Surface Tension | 31.997 dyn/cm📊 OPERA |
| Thermal Conductivity | 113.744 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 | 3 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 59.386 cm^3/mol📊 OPERA |
| Polarizability | 23.543 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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