2,6-Octadiene-1-thiol, 3,7-dimethyl- (CAS 38237-00-2) — Citrus Top Note Fragrance Ingredient
2,6-Octadiene-1-thiol, 3,7-dimethyl-
CAS 38237-00-2
What Is 2,6-Octadiene-1-thiol, 3,7-dimethyl-?
2,6-Octadiene-1-thiol, 3,7-dimethyl- is a synthetic fragrance ingredient used to create tropical fruit and citrus nuances in perfumes. It’s found in high-end fragrances and some fruity body care products. This molecule matters because it delivers intense, authentic tropical notes that are difficult to obtain from natural sources, allowing perfumers to craft vibrant, exotic accords with precision.
Safety Profile
USE WITH AWARENESSWhat Does 2,6-Octadiene-1-thiol, 3,7-dimethyl- Smell Like?
A powerhouse of tropical intensity, this thiol bursts with an initial punch of overripe guava and passionfruit, dripping with juicy sweetness. As it evolves, a sharper grapefruit peel edge emerges, balanced by a faint sulfurous undertone that adds complexity. The dry-down reveals a surprisingly clean, almost ozonic character reminiscent of sea spray, though traces of the initial fruitiness linger for hours. At high concentrations, it can overwhelm, but when properly diluted, it creates an irresistible tropical halo around floral and citrus compositions.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used at 0.2% to create the signature sun-ripened mango effect, blending seamlessly with ylang-ylang and coconut milk for a photorealistic tropical cocktail.
Provides the juicy pink grapefruit illusion in the top notes, enhancing the natural citrus oils with an extra dimension of tropical sweetness.
2D Molecular Structure
SMILES: CC(C)=CCCC(C)=CCS
Chemistry, Properties & Perfumer Guide
The Chemistry
This unsaturated thiol belongs to the class of sulfur-containing terpenoids, structurally related to grapefruit mercaptan. Synthesized through nucleophilic addition to terpene precursors, its configuration allows for potent odor detection at extremely low concentrations. The molecule’s reactivity requires careful handling during formulation to prevent oxidation and preserve its characteristic fruity notes.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Odor Threshold | Extremely low (ppb range) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.1-0.5% | Up to 1% | Tropical fruit effects |
| Body Care | 0.01-0.1% | Up to 0.3% | Fruity top notes |
Classic Accords
Tip: Always pre-dilute to 1% in DPG before incorporating into blends to ensure even distribution.
Alternatives & Comparisons
For less sulfurous tropical effects with better stability in alkaline formulations.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No specific restrictions under current IFRA standards (as of Amendment 49).
GHS Classification
RIFM Assessment
Currently under review by RIFM for comprehensive safety assessment.
Sustainability
As a synthetic material, production involves petrochemical feedstocks but requires minimal quantities due to extreme potency. Some manufacturers are exploring bio-based routes using fermentation-derived terpenes.
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References
- Brenna et al. (2012). Tropical Thiols in Modern Perfumery. Flavour and Fragrance Journal. DOI:10.1002/ffj.2105
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID9068081
Physical Properties
| Molecular Weight | 170.31 g/mol🔬 EPA CompTox |
| Density | 0.883 g/cm^3📊 OPERA |
| Boiling Point | 238.093 °C📊 OPERA |
| Melting Point | -55.456 °C📊 OPERA |
| Flash Point | 86.433 °C📊 OPERA |
| Refractive Index | 1.488 Dimensionless📊 OPERA |
| Molar Volume | 194.483 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 4.241 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 4.241 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 4.24 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.05 Log10 unitless📊 OPERA |
| Water Solubility | 0.001 mol/L📊 OPERA |
| Henry's Law Constant | 0.001 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.147 mmHg📊 OPERA |
| Viscosity | 1.467 cP📊 OPERA |
| Surface Tension | 26.37 dyn/cm📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 0 Ų💻 Computed |
| H-Bond Donors | 1 count💻 Computed |
| H-Bond Acceptors | 1 count💻 Computed |
| Rotatable Bonds | 4 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 56.075 cm^3/mol📊 OPERA |
| Polarizability | 22.23 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.
