(2-endo,3-exo)-Ethyl 3-(1-methylethyl)bicyclo[2.2.1]hept-5-ene-2-carboxylate (CAS 116044-44-1) — Woody Middle Note Fragrance Ingredient
(2-endo,3-exo)-Ethyl 3-(1-methylethyl)bicyclo[2.2.1]hept-5-ene-2-carboxylate
CAS 116044-44-1
What Is (2-endo,3-exo)-Ethyl 3-(1-methylethyl)bicyclo[2.2.1]hept-5-ene-2-carboxylate?
This synthetic fragrance ingredient is a specialized bicyclic compound used in modern perfumery to create unique woody-green effects. You might encounter it in niche fragrances seeking avant-garde scent profiles. While not widely known, it offers perfumers a tool for crafting unconventional accords that stand out from traditional compositions.
Safety Profile
GENERALLY SAFEWhat Does (2-endo,3-exo)-Ethyl 3-(1-methylethyl)bicyclo[2.2.1]hept-5-ene-2-carboxylate Smell Like?
This bicyclic ester delivers a crisp, modern woody-green character with subtle camphoraceous undertones. The initial impression is reminiscent of freshly split pine wood with a cool, almost minty edge. As it evolves, a clean woody backbone emerges, supported by faintly resinous and slightly fruity nuances. The dry-down reveals a persistent woody-mossy character that blends well with modern chypre and fougère bases.
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
(2-endo,3-exo)-Ethyl 3-(1-methylethyl)bicyclo[2.2.1]hept-5-ene-2-carboxylate belongs to the bicyclic terpenoid esters class, structurally related to camphor derivatives. The molecule features a norbornene core with ester and isopropyl substituents in specific spatial configurations. Synthesis typically involves Diels-Alder reactions of cyclopentadiene with appropriate dienophiles, followed by esterification. The stereochemistry at the 2-endo and 3-exo positions creates unique olfactory properties distinct from simpler terpenoid esters.
Physical & Chemical Properties
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Modern woody modifier |
| Functional Fragrance | 0.1-1% | Up to 3% | Green-woody accent |
Classic Accords
Tip: Use as a bridge between citrus top notes and woody base materials in contemporary masculine fragrances.
Alternatives & Comparisons
Similar woody-camphoraceous character but more traditional and less green.
Offers floral-woody aspects with better diffusion but lacks the bicyclic character.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted by IFRA standards.
RIFM Assessment
No RIFM assessment publicly available for this specific compound.
Sustainability
As a synthetic material, this ingredient avoids natural resource depletion concerns. However, its synthesis requires petrochemical feedstocks and energy-intensive processes. The specialized nature of its production means it has a relatively high carbon footprint compared to bulk aroma chemicals.
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Ingredient Data Sheet
CAS 116044-44-1Physical 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 | 103.2 °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: DTXSID5051315
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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