2,4,5-Trimethylthiazole (CAS 13623-11-5) — Sweet Middle Note Fragrance Ingredient
2,4,5-Trimethylthiazole
CAS 13623-11-5
What Is 2,4,5-Trimethylthiazole?
2,4,5-Trimethylthiazole is a synthetic aroma chemical that contributes to the savory, roasted, and nutty aspects of many food flavors and fragrances. You might encounter it in coffee, chocolate, or meat flavorings. This molecule matters because it adds depth and complexity to gourmand and savory fragrance compositions, creating a bridge between sweet and umami notes.
Safety Profile
GENERALLY SAFEWhat Does 2,4,5-Trimethylthiazole Smell Like?
2,4,5-Trimethylthiazole delivers an intense, roasted character reminiscent of freshly brewed coffee grounds and roasted nuts. The initial burst is powerfully savory, with a meaty undertone that evolves into a warm, toasted bread-like heart. As it dries down, it reveals a subtle earthy-green nuance that lingers close to the skin. The effect is like walking past a coffee roastery where the beans have just reached second crack – rich, slightly smoky, and mouthwateringly complex.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used here to amplify the dark coffee and chocolate accord, adding a photorealistic roasted edge to the gourmand heart.
Contributes to the hyper-realistic espresso note, blending with vanillic sweetness to create a coffee shop ambiance.
Chemistry, Properties & Perfumer Guide
The Chemistry
2,4,5-Trimethylthiazole belongs to the thiazole class of heterocyclic compounds, characterized by a five-membered ring containing both sulfur and nitrogen atoms. While trace amounts occur naturally in roasted foods, commercial material is synthesized through condensation reactions of α-haloketones with thioamides. The three methyl groups at positions 2, 4, and 5 create steric hindrance that influences both volatility and odor strength. The molecule’s planar structure allows for strong interactions with olfactory receptors tuned to detect roasted and savory notes.
Physical & Chemical Properties
| Boiling Point | ~180-185 °C (estimated) |
|---|---|
| Density | ~1.05 g/cm³ (estimated) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.1-0.5% | Up to 1% | Powerful modifier for coffee/chocolate accords |
| Functional Fragrance | 0.01-0.1% | Up to 0.2% | Adds realism to food flavors |
Classic Accords
Tip: Use in trace amounts with vanillic materials to prevent overpowering the composition.
Alternatives & Comparisons
Offers similar roasted character but with more green, tomato leaf aspects at lower concentrations.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No IFRA restrictions currently apply to 2,4,5-Trimethylthiazole.
RIFM Assessment
RIFM has evaluated related thiazoles but no specific assessment found for this isomer.
Sustainability
As a synthetic material, 2,4,5-Trimethylthiazole has minimal environmental impact in production. The synthesis uses common petrochemical feedstocks with efficient catalytic processes. Its high potency means very small quantities are needed, reducing material requirements compared to natural extracts with similar odor profiles.
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References
- Burdock, G.A. (2010). Fenaroli’s Handbook of Flavor Ingredients. CRC Press. ISBN 9781439847503
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
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