2-(4-Methyl-5-thiazolyl)ethyl butanoate (CAS 94159-31-6) — Sweet Top Note Fragrance Ingredient
2-(4-Methyl-5-thiazolyl)ethyl butanoate
CAS 94159-31-6
What Is 2-(4-Methyl-5-thiazolyl)ethyl butanoate?
2-(4-Methyl-5-thiazolyl)ethyl butanoate is a synthetic fragrance ingredient used to add fruity, tropical nuances to perfumes and flavored products. You’ll encounter it in tropical-inspired fragrances and some fruity food flavorings. This molecule matters because it provides a unique sweet-tart character that mimics exotic fruits, helping perfumers create vibrant, summery accords without relying solely on natural extracts.
Safety Profile
USE WITH AWARENESSWhat Does 2-(4-Methyl-5-thiazolyl)ethyl butanoate Smell Like?
This thiazole derivative bursts with a juicy, tropical fruit character reminiscent of passionfruit and guava, with a tart green apple edge. The initial impression is intensely sweet-fruity, evolving into a more vegetal, slightly herbal heart with subtle peppery undertones. As it dries down, it reveals a clean, almost ozonic quality that prevents cloying sweetness. The thiazole ring contributes a distinctive sulfurous nuance that adds complexity, making it particularly useful for creating modern fruity-floral compositions that need depth beyond simple ester fruitiness.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used to amplify the pineapple accord, adding realistic tartness and tropical depth to the fruity top notes while preventing excessive sweetness.
Contributes to the cocktail-like lime and coconut accord, bridging citrus and tropical fruit notes with its juicy-thiolic character.
Enhances the mint-apple opening with its tart green fruit facets, creating a more dynamic fruity freshness.
Works alongside citrus notes to create the fragrance’s signature crisp, fruity-floral character with tropical undertones.
Provides the bright raspberry note with additional dimensionality through its tart-thiolic fruitiness.
Chemistry, Properties & Perfumer Guide
The Chemistry
2-(4-Methyl-5-thiazolyl)ethyl butanoate belongs to the thiazole class of heterocyclic compounds, characterized by a sulfur and nitrogen-containing five-membered ring. While not found in nature, its structure mimics certain sulfur-containing fruit volatiles. Synthesized through esterification of 4-methyl-5-thiazoleethanol with butyric acid, this molecule combines fruity ester characteristics with the distinctive sulfurous notes of the thiazole ring. The methyl group at the 4-position and ethyl ester chain create optimal volatility for top-note applications while maintaining sufficient persistence.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Boiling Point | Estimated 250-280 °C |
| Density | Approx. 1.05 g/cm³ |
| Solubility | Soluble in alcohol, oils; insoluble in water |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Fruity top note enhancer |
| Functional Fragrance | 0.1-0.5% | Up to 1% | Tropical fruit effects |
| Flavor | 10-50 ppm | Up to 100 ppm | Tropical fruit nuances |
Classic Accords
Tip: Use in trace amounts with citrus oils to create more complex fruity top notes that avoid simple sweetness.
Alternatives & Comparisons
When a more caramelized, cooked fruit character is desired instead of fresh tartness.
For simpler, more direct fruity effects without sulfurous complexity.
When a stronger sulfurous tropical fruit effect is needed.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted by IFRA. Approved for use under general fragrance guidelines.
RIFM Assessment
Under evaluation by RIFM; preliminary data suggests safe use at current levels.
Sustainability
As a synthetic material, this ingredient avoids agricultural supply chain issues associated with natural tropical fruit extracts. Production typically involves petrochemical feedstocks, though green chemistry approaches could potentially utilize bio-based butyric acid. Its high potency means small quantities suffice, reducing environmental burden per kilogram of fragrance produced.
Explore 2-(4-Methyl-5-thiazolyl)ethyl butanoate
Browse essential oils and aroma compounds.
Browse on iHerb →Affiliate disclosure: we may earn a small commission at no extra cost to you.
References
- Burdock, G.A. (2010). Fenaroli’s Handbook of Flavor Ingredients. CRC Press. ISBN 9781439832278
- Pybus, D.H. (1999). The Chemistry of Fragrances. RSC Publishing. ISBN 0854045283
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data error
