4-Methyl-5-thiazoleethanol acetate (CAS 656-53-1) — Sweet Heart to base Note Fragrance Ingredient
4-Methyl-5-thiazoleethanol acetate
CAS 656-53-1
What Is 4-Methyl-5-thiazoleethanol acetate?
4-Methyl-5-thiazoleethanol acetate is a synthetic fragrance compound used to add unique meaty, roasted nuances to savory flavors and gourmand perfumes. You’ll encounter it in high-end fragrances and some savory food flavorings. This molecule matters because it bridges the gap between food and fragrance worlds, creating unexpected depth in compositions that play with umami and caramelized notes.
Safety Profile
USE WITH AWARENESSWhat Does 4-Methyl-5-thiazoleethanol acetate Smell Like?
A complex chameleon that begins with a sharp, almost burnt matchstick sulfurousness before unfolding into rich meat broth and roasted nuts. As it dries down, it reveals surprising caramelized sugar facets reminiscent of crème brûlée’s burnt sugar crust. The sulfurous edge persists throughout, giving it an addictive savory-sweet tension that makes it invaluable for modern gourmands seeking depth beyond vanilla.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used sparingly here to amplify the oud’s animalic facets while adding a caramelized dimension that bridges the gap between the rose and leather notes.
Provides the haunting roasted coffee bean illusion in this dark gourmand, interacting with the rum and chocolate notes to create a boozy tiramisu effect.
2D Molecular Structure
SMILES: CC(=O)OCCC1=C(C)N=CS1
Chemistry, Properties & Perfumer Guide
The Chemistry
This thiazole derivative belongs to the heterocyclic sulfur compounds class, structurally featuring both a thiazole ring and acetate ester group. While not found in nature, it mimics Maillard reaction products found in roasted meats and coffee. Industrial synthesis typically involves reacting 4-methylthiazole with ethylene oxide followed by acetylation. The sulfur atom’s lone pair electrons contribute to its potent odor characteristics at extremely low thresholds.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Boiling Point | ~250 °C (estimated) |
| Density | ~1.15 g/cm³ (estimated) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.01-0.1% | Up to 0.3% | Used in trace amounts for savory accents |
| Gourmand Fragrances | 0.05-0.2% | Up to 0.5% | Amplifies caramelized notes |
Classic Accords
Tip: Always pre-dilute to 1% or lower before incorporating – its sulfurous facets can overwhelm blends at full strength.
Alternatives & Comparisons
For a brighter popcorn-like effect when less meatiness is desired. Shares similar thiazole structure but with acetyl instead of ethanol acetate group.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No specific IFRA restrictions. General sulfur compound guidelines apply.
GHS Classification
RIFM Assessment
Not currently evaluated by RIFM. Use recommended at industry-standard low levels.
Sustainability
As a synthetic material, production involves petrochemical feedstocks but requires minimal quantities due to extreme potency. No known ecological accumulation concerns at usage levels.
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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 errorPhysicochemical Properties
DTXSID: DTXSID8060959
Physical Properties
| Molecular Weight | 185.24 g/mol🔬 EPA CompTox |
| Density | 1.147 g/cm^3🔬 EPA CTX |
| Boiling Point | 247.574 °C📊 OPERA |
| Melting Point | 46.603 °C📊 OPERA |
| Flash Point | 110.897 °C📊 OPERA |
| Refractive Index | 1.523 Dimensionless📊 OPERA |
| Molar Volume | 157.725 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 1.684 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 1.678 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 1.684 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.72 Log10 unitless📊 OPERA |
| Water Solubility | 0.013 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.01 mmHg📊 OPERA |
| Viscosity | 6.673 cP📊 OPERA |
| Surface Tension | 38.271 dyn/cm📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 39.19 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 4 count💻 Computed |
| Rotatable Bonds | 3 count💻 Computed |
| Aromatic Rings | 1 count💻 Computed |
| Molar Refractivity | 48.143 cm^3/mol📊 OPERA |
| Polarizability | 19.085 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.
