2-Isopropyl-4-methylthiazole (CAS 15679-13-7) — Green Top to middle Note Fragrance Ingredient
2-Isopropyl-4-methylthiazole
CAS 15679-13-7
What Is 2-Isopropyl-4-methylthiazole?
2-Isopropyl-4-methylthiazole is a synthetic fragrance compound that imparts green, vegetable-like aromas with earthy undertones. It’s primarily used in fine fragrances and functional products to create naturalistic green notes. This ingredient matters because it helps perfumers replicate the fresh-cut stems and leafy aspects found in nature without relying on plant extracts, offering stability and consistency in formulations.
Safety Profile
USE WITH AWARENESSWhat Does 2-Isopropyl-4-methylthiazole Smell Like?
2-Isopropyl-4-methylthiazole bursts with an intensely green, almost aggressive vegetal character reminiscent of crushed tomato leaves and freshly cut grass stems. The initial sharpness mellows into a warm, earthy undertone with subtle nutty nuances, like the husky aroma of pea vines in sunlight. As it dries down, it maintains a persistent greenness but develops a smoother, almost mushroom-like earthiness that blends well with woody bases. The overall effect is like walking through a humid greenhouse filled with young vegetable plants.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used to amplify the hyper-realistic tomato leaf accord, creating an illusion of sun-warmed vegetation in this groundbreaking green floral.
Provides the wet-earth vegetal facets that evoke monsoon-soaked gardens, paired with melon and ginger notes.
2D Molecular Structure
SMILES: CC(C)C1=NC(C)=CS1
Chemistry, Properties & Perfumer Guide
The Chemistry
2-Isopropyl-4-methylthiazole belongs to the thiazole class of heterocyclic compounds, characterized by a five-membered ring containing both sulfur and nitrogen atoms. While thiazoles occur naturally in some foods (like tomatoes and passionfruit), this particular variant is exclusively synthetic. It’s typically produced through condensation reactions of α-haloketones with thioamides. The isopropyl group at position 2 contributes to its volatility, while the methyl group at position 4 modifies its electron density, affecting both odor characteristics and chemical reactivity.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Boiling Point | ~210 °C (estimated) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.1-0.5% | Up to 1% | Powerful green modifier |
| Functional Products | 0.01-0.1% | Up to 0.2% | Adds naturalistic green character |
Classic Accords
Tip: Use sparingly in citrus colognes to add stemmy depth without overpowering the top notes.
Alternatives & Comparisons
When a softer, more floral green note is needed without the intense vegetal punch of the thiazole.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No IFRA restrictions currently apply to this material (as of 54th Amendment).
GHS Classification
RIFM Assessment
RIFM has reviewed available data and found no significant concerns at typical fragrance usage levels.
Sustainability
As a synthetic material, 2-isopropyl-4-methylthiazole avoids agricultural land use and seasonal variability. Its production requires controlled chemical processes with standard industrial waste management. The sulfur content necessitates proper handling to prevent atmospheric emissions, but overall environmental impact is lower than intensive crop cultivation for similar natural effects.
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Physicochemical Properties
DTXSID: DTXSID0047664
Physical Properties
| Molecular Weight | 141.23 g/mol🔬 EPA CompTox |
| Density | 1 g/cm^3🔬 EPA CTX |
| Boiling Point | 175 °C🔬 EPA CTX |
| Melting Point | -5.292 °C📊 OPERA |
| Flash Point | 53.714 °C📊 OPERA |
| Refractive Index | 1.515 Dimensionless📊 OPERA |
| Molar Volume | 138.484 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 2.288 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 2.26 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 2.288 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.31 Log10 unitless📊 OPERA |
| Water Solubility | 0.269 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 2.884 mmHg📊 OPERA |
| Viscosity | 3.073 cP📊 OPERA |
| Surface Tension | 32.94 dyn/cm📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 12.89 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 | 41.738 cm^3/mol📊 OPERA |
| Polarizability | 16.546 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.
