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

1. Identity & Chemical Information

2-Isobutyl thiazole is a chemical compound commonly used in flavor and fragrance applications. Its IUPAC name is 2-(2-methylpropyl)-1,3-thiazole. The CAS number for this compound is 18640-74-9. It is also identified by the FEMA number 2205. The molecular formula is C7H11NS, and it has a molecular weight of 141.23 g/mol. The compound features a thiazole ring, which is crucial for its characteristic odor profile. The presence of the isobutyl group contributes to its distinct green and earthy notes, making it relevant in flavor and fragrance formulations.

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 having a fresh, pea-like scent with a moderate to high intensity. The compound is primarily used as an impact note in flavor formulations, providing a realistic green and vegetal character. Its odor threshold is relatively low, allowing it to be effective even at minimal concentrations. In flavor applications, it is used to enhance the freshness and authenticity of vegetable and herbaceous profiles.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

2-Isobutyl thiazole naturally occurs in various foods, including green bell peppers, tomatoes, and peas. It is formed through the Maillard reaction, a chemical reaction between amino acids and reducing sugars that occurs during the cooking process. This compound is significant for its contribution to the "natural flavor" designation, as it is found in many natural food sources and can be derived from natural processes.

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

4. Use in Flavors

In flavor applications, 2-isobutyl thiazole is used across various categories, including vegetable, herb, and savory flavors. It serves as a functional component to impart a fresh, green note, enhancing the authenticity of the flavor profile. Typical use levels in finished food products range from 0.1 to 5 ppm, depending on the desired intensity and application. It is stable under typical processing conditions but may degrade under extreme heat or acidic environments.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

2-Isobutyl thiazole is utilized in fragrance formulations to provide a green, earthy note, often used in the creation of natural and fresh accords. It is found in fragrance families such as green, chypre, and fougère. The compound acts as a modifier or impact note, contributing to the top and middle notes of a fragrance composition. Typical concentrations in fragrance products are low, often less than 0.1%, due to its potent aroma.

Citation hooks: FlavScents; IFRA; fragrance chemistry texts

6. Regulatory Status (Regional Overview)

In the United States, 2-isobutyl thiazole is recognized as GRAS (Generally Recognized As Safe) by FEMA for flavor use. In the European Union, it is regulated under Regulation (EC) No 1334/2008 and has an assigned FL number. The United Kingdom follows similar regulations post-Brexit. In Asia, including Japan and China, it is generally accepted for use in flavors, though specific regulations may vary. In Latin America, countries like Brazil and those in MERCOSUR have aligned regulations for its use in flavors and fragrances.

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 an acceptable daily intake (ADI) not specifically established but deemed low risk. Dermal exposure in fragrance applications is generally safe, with no significant irritation or sensitization reported at typical use levels. Inhalation exposure is minimal due to its low volatility, but occupational exposure should be managed with standard safety practices. The risk profiles for food and fragrance applications are similar, with no significant differences noted.

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 note that enhances the authenticity of both flavor and fragrance formulations. It synergizes well with other green and herbaceous compounds, such as hexenal and cis-3-hexenol. Formulators should be cautious of its potent aroma, as overuse can lead to an overpowering or artificial character. It is often under-utilized in complex formulations where a subtle green note is desired.

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. Industry practices are well-documented, though specific use levels may vary based on formulation goals. Some data gaps exist in the precise quantification of its natural occurrence in various food sources, but these do not significantly impact its application or safety assessment.

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 2026-04-17 18:51:15 GMT (p2)