3-Mercapto-3-methylbutyl formate (CAS 50746-10-6) — Sweet Top to middle Note Fragrance Ingredient
3-Mercapto-3-methylbutyl formate
CAS 50746-10-6
What Is 3-Mercapto-3-methylbutyl formate?
3-Mercapto-3-methylbutyl formate is a synthetic fragrance ingredient often used to create tropical, fruity, or musky notes in perfumes and body care products. You’ll encounter it in modern fragrances, especially those with exotic or tropical fruit accords. This molecule matters because it can mimic the scent of ripe tropical fruits at extremely low concentrations, making it a powerful tool for perfumers seeking authentic fruity nuances without using natural extracts that may vary in quality or sustainability.
Safety Profile
USE WITH AWARENESSWhat Does 3-Mercapto-3-methylbutyl formate Smell Like?
A powerful, diffusive aroma that bursts with tropical fruitiness – imagine overripe passionfruit dripping with juice, crossed with the sulfury tang of a freshly cut grapefruit. The top note has a slightly rubbery, musky undertone that quickly gives way to a sweet, almost candied mango-like heart. As it dries down, it leaves a lingering impression of exotic fruits with a faintly animalic muskiness, like sun-warmed skin after eating papaya. The sulfurous edge keeps it from being cloying, adding an addictive quality that makes it perfect for modern fruity-floral compositions.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used to amplify the lychee and raspberry top notes, adding a juicy, mouthwatering quality that makes the fruit accord smell hyper-realistic yet sophisticated.
Provides a tropical fruit facet to the vanilla-orchid base, creating an addictive contrast between sweet and sulfury notes that defines the fragrance’s signature.
2D Molecular Structure
SMILES: CC(C)(S)CCOC=O
Chemistry, Properties & Perfumer Guide
The Chemistry
3-Mercapto-3-methylbutyl formate belongs to the class of sulfur-containing esters, combining a thiol group with a formate ester. The molecule’s structure features a branched carbon chain that contributes to its tropical fruit character. While it doesn’t occur naturally, its aroma closely resembles certain sulfur-containing compounds found in passionfruit and guava. Industrial synthesis typically involves the reaction of 3-methyl-3-buten-1-ol with hydrogen sulfide followed by formylation, requiring careful control to prevent unwanted byproducts. The sulfur atom is crucial to its odor profile, creating the characteristic ‘tropical’ effect at concentrations as low as 0.1 ppm.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Boiling Point | Approx. 200-210 °C (estimated) |
| Density | Approx. 1.0 g/cm³ (estimated) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.05-0.2% | Up to 0.5% | Provides tropical fruit accents |
| Body Care | 0.01-0.1% | Up to 0.2% | Limited in leave-on products |
Classic Accords
Tip: Use in trace amounts (0.01-0.05%) to enhance fruity top notes without overpowering the composition.
Alternatives & Comparisons
Less sulfury with more grapefruit character, useful when a cleaner tropical effect is desired.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted by IFRA, but recommended usage levels should be followed due to potential sensitization at higher concentrations.
GHS Classification
RIFM Assessment
RIFM has evaluated this material and recommends keeping concentrations below 0.2% in fine fragrances.
Sustainability
As a synthetic material, 3-Mercapto-3-methylbutyl formate offers consistent quality and reduces pressure on natural resources. While the production requires sulfur-containing precursors, modern manufacturing processes minimize waste and environmental impact. Its high potency means very small quantities are needed, reducing the overall carbon footprint compared to natural extracts with similar olfactory effects.
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References
- Burdock, G.A. (2010). Fenaroli’s Handbook of Flavor Ingredients. CRC Press.
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 50746-10-6Physical Properties
| Molecular Weight | 148.23 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 1.4🔬 PubChem |
| Boiling Point | 181 °C🔬 EPA CompTox |
| log Kp (skin permeability) | -2.61💻 Calculated |
| SMILES | CC(C)(CCOC=O)S🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
Odor & Flavor
| Primary Descriptors | roastedsulfurous• leffingwell |
| Functional Groups | etherthiol💻 RDKit |
Sensory Thresholds
| Odor Detection Threshold | 0 ppm (n=3)📖 van Gemert |
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: DTXSID60198790
Physical Properties
| Molecular Weight | 148.22 g/mol🔬 EPA CompTox |
| Density | 1.03 g/cm^3🔬 EPA CTX |
| Boiling Point | 181 °C🔬 EPA CTX |
| Melting Point | -55.897 °C📊 OPERA |
| Flash Point | 76.246 °C📊 OPERA |
| Refractive Index | 1.458 Dimensionless📊 OPERA |
| Molar Volume | 145.353 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 1.622 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 1.622 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 1.587 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 3.46 Log10 unitless📊 OPERA |
| Water Solubility | 0.04 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 1.316 mmHg📊 OPERA |
| Viscosity | 1.408 cP📊 OPERA |
| Surface Tension | 29.743 dyn/cm📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 26.3 Ų💻 Computed |
| H-Bond Donors | 1 count💻 Computed |
| H-Bond Acceptors | 3 count💻 Computed |
| Rotatable Bonds | 4 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 39.64 cm^3/mol📊 OPERA |
| Polarizability | 15.715 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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