2-Methyl-5-(methylthio)furan (CAS 13678-59-6) — Spicy Top to Middle Note Fragrance Ingredient
2-Methyl-5-(methylthio)furan
CAS 13678-59-6
What Is 2-Methyl-5-(methylthio)furan?
2-Methyl-5-(methylthio)furan is a synthetic aroma chemical that adds meaty, roasted nuances to fragrances and flavorings. You might encounter it in savory gourmand perfumes or processed food flavorings. This molecule matters because it provides an authentic ‘cooked’ character at extremely low concentrations, enhancing the realism of meaty or roasted notes in compositions where natural extracts would be impractical.
Safety Profile
USE WITH AWARENESSWhat Does 2-Methyl-5-(methylthio)furan Smell Like?
A powerhouse of savory intensity, 2-methyl-5-(methylthio)furan erupts with an immediate impression of sizzling beef fat and pan drippings. The top note carries a metallic blood-like sharpness that quickly mellows into roasted onion skins and blackened garlic. As it dries, the sulfurous edge softens into a lingering umami richness reminiscent of soy sauce reduction or dried porcini mushrooms. In trace amounts, it adds incredible depth to gourmand bases, making abstract sweet notes smell inexplicably edible and complex.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used at parts-per-million levels to amplify the leather accord’s animalic warmth, creating the illusion of sun-baked suede with microscopic meaty nuances that register subconsciously.
Provides a visceral smoked-meat undertone to the dark resinous blend, making the cannabis accord smell more narcotic and physically present.
2D Molecular Structure
SMILES: CSC1=CC=C(C)O1
Chemistry, Properties & Perfumer Guide
The Chemistry
This heterocyclic furan derivative belongs to the organosulfur compounds, with a methylthio group at the 5-position enhancing its volatility and odor potency. Industrially synthesized through nucleophilic substitution reactions on furan precursors, its structure combines the electron-rich furan ring with sulfur’s nucleophilic character. The methylthio group’s orientation significantly impacts its odor threshold, making stereochemistry crucial – even trace impurities can drastically alter its sensory profile.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Odor Threshold | Extremely low (ppb range) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.001-0.01% | Max 0.05% | For meaty leather effects |
| Functional Fragrance | 0.0001-0.001% | Max 0.005% | In savory home care products |
Classic Accords
Tip: Always pre-dilute to 0.1% or lower before incorporation – this material can overwhelm a blend at concentrations invisible to the naked eye.
Alternatives & Comparisons
Even more potent meaty sulfur compound, suitable when an extreme roasted beef effect is desired at ultralow doses.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No specific restrictions under current IFRA standards (Amendment 49), but recommended for expert use only due to potency.
GHS Classification
RIFM Assessment
Not currently listed in RIFM’s database – considered a specialty material with limited exposure scenarios.
Sustainability
Synthetic production avoids agricultural impacts but requires careful handling of sulfur-containing precursors. The extreme potency means minimal quantities are needed, reducing overall environmental load compared to natural meat extracts. Supply chain is stable as it’s produced from petrochemical feedstocks.
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References
- Mottram, D.S. (1998). Flavor formation in meat and meat products: a review. Food Chemistry, 62(4), 415-424. DOI:10.1016/S0308-8146(98)00076-4
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 13678-59-6Physical Properties
| Molecular Weight | 128.19 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 2.7🔬 PubChem |
| Boiling Point | 66 °C🔬 EPA CompTox |
| log Kp (skin permeability) | -1.565💻 Calculated |
| SMILES | CC1=CC=C(O1)SC🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
Odor & Flavor
| Primary Descriptors | burntsulfurous• leffingwell |
| Functional Groups | aromatic💻 RDKit |
| 2-Methyl-5-thiomethylfuran has a very strong, sulfurated odor.📖 Fenaroli | |
Regulatory Status
| IOFI Classification | Nature Identical📖 Fenaroli |
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: DTXSID9065578
Physical Properties
| Molecular Weight | 128.19 g/mol🔬 EPA CompTox |
| Density | 1.057 g/cm^3🔬 EPA CTX |
| Boiling Point | 172.336 °C📊 OPERA |
| Melting Point | -13.321 °C📊 OPERA |
| Flash Point | 54.372 °C📊 OPERA |
| Refractive Index | 1.529 Dimensionless📊 OPERA |
| Molar Volume | 118.344 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 2.408 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 2.408 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 2.408 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.42 Log10 unitless📊 OPERA |
| Water Solubility | 0.016 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 4.813 mmHg📊 OPERA |
| Surface Tension | 35.248 dyn/cm📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 13.14 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 2 count💻 Computed |
| Rotatable Bonds | 1 count💻 Computed |
| Aromatic Rings | 1 count💻 Computed |
| Molar Refractivity | 36.498 cm^3/mol📊 OPERA |
| Polarizability | 14.469 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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