FlavScents AInsights Entry for 2-Isobutyl Thiazole (CAS: 18640-74-9)

1. Identity & Chemical Information

• Common Name(s): 2-Isobutyl thiazole
• IUPAC Name: 2-(2-methylpropyl)-1,3-thiazole
• CAS Number: 18640-74-9
• FEMA Number: 3209
• Other Identifiers: FL No. 15.034
• Molecular Formula: C7H11NS
• Molecular Weight: 141.23 g/mol

2-Isobutyl thiazole is a heterocyclic compound characterized by a thiazole ring, which is a five-membered ring containing both sulfur and nitrogen atoms. The presence of the isobutyl group contributes to its distinct odor profile. The thiazole ring is crucial for its odor characteristics, often described as green and earthy, which are significant in flavor and fragrance applications.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

2-Isobutyl thiazole is known for its potent green, earthy, and slightly nutty aroma. It is often described as reminiscent of freshly cut green peppers, which makes it a valuable impact note in flavor formulations. The compound has a low odor threshold, allowing it to impart its characteristic scent even at low concentrations. Its sensory role is typically as an impact note, providing a fresh, green character to both flavors and fragrances.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

2-Isobutyl thiazole naturally occurs in various foods, most notably in green bell peppers, where it contributes to their characteristic aroma. It is also found in other vegetables and some fruits. The compound can form through the Maillard reaction, a chemical reaction between amino acids and reducing sugars that occurs during the cooking process, enhancing the flavor profile of cooked foods.

Citation hooks: FlavScents; food chemistry literature; EFSA/JECFA monographs

4. Use in Flavors

2-Isobutyl thiazole is widely used in flavor formulations, particularly in vegetable and savory flavors. It is commonly used to enhance the green, fresh notes in products such as soups, sauces, and snacks. Typical use levels in finished food products range from 0.1 to 5 ppm, depending on the desired intensity and the specific application. The compound is relatively stable under typical processing conditions, but formulators should consider its volatility when used in high-temperature applications.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

In the fragrance industry, 2-isobutyl thiazole is used to impart green, fresh notes to various fragrance families, including chypre and fougère. It serves as a modifier or impact note, often used in trace amounts to enhance the realism of natural green scents. Its volatility makes it suitable for top and middle notes in fragrance compositions.

Citation hooks: FlavScents; IFRA; fragrance chemistry texts

6. Regulatory Status (Regional Overview)

• United States: Recognized as GRAS by FEMA for flavor use.
• European Union: Approved under Regulation (EC) No 1334/2008 with FL No. 15.034.
• United Kingdom: Aligns with EU regulations post-Brexit.
• Asia: Approved for use in Japan and China, with specific restrictions varying by country.
• Latin America: Generally accepted, but specific regulations may vary by country.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

For oral exposure, 2-isobutyl thiazole is considered safe at the levels typically used in food products, with a wide margin of safety. Dermal exposure in fragrance applications is generally low risk, but formulators should consider potential sensitization in sensitive individuals. Inhalation exposure is minimal due to its low volatility at typical use levels, but occupational exposure should be managed with standard safety practices.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

2-Isobutyl thiazole is valued for its ability to impart a fresh, green character to both flavors and fragrances. It synergizes well with other green and herbal notes, enhancing the overall freshness of a formulation. However, its potent aroma means it can easily be overused, leading to an overpowering scent. Formulators should carefully balance its concentration to achieve the desired effect without overwhelming other components.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

The data on 2-isobutyl thiazole is well-established, with comprehensive sensory and regulatory information available. While industry practices are generally consistent, some variability in natural occurrence data may exist due to differences in agricultural and processing conditions.

Citation hooks: FlavScents

QA Check

• All required sections 1–9 are present
• "Citation hooks:" line is present under each section
• Flavor section includes ppm ranges
• Toxicology section covers oral, dermal, inhalation
• Regulatory section mentions US, EU, UK, Asia, Latin America
• If complex natural material: includes section 5a (not applicable here)

About FlavScents AInsights (Disclosure)
FlavScents AInsights integrates information from authoritative government, scientific, academic, and industry sources to provide applied, exposure-aware insight into flavor and fragrance materials. Data are drawn from regulatory bodies, expert safety panels, peer-reviewed literature, public chemical databases, and long-standing professional practice within the flavor and fragrance community. Where explicit published values exist, they are reported directly; where gaps remain, AInsights reflects widely accepted industry-typical practice derived from convergent sensory behavior, historical commercial use, regulatory non-objection, and expert consensus. All such information is clearly labeled to distinguish documented data from professional guidance or informed estimation, with the goal of offering transparent, practical, and scientifically responsible context for researchers, formulators, and regulatory specialists. This section is generated using advanced computational language modeling to synthesize and structure information from established scientific and regulatory knowledge bases, with the intent of supporting—not replacing—expert review and judgment.

Generated 2026-08-10 18:42:16 GMT (p2)