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 distinctive odor profile. The thiazole ring is crucial for its odor characteristics, often described as green and earthy, reminiscent of raw vegetables.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

2-Isobutyl thiazole is known for its potent green, earthy, and vegetable-like odor, often associated with the aroma of freshly cut green peppers. It is a high-impact aroma compound, meaning even small concentrations can significantly influence the overall scent profile. Its odor threshold is relatively low, making it effective as an impact note in flavor formulations. The compound is primarily used to impart a fresh, green character to flavor and fragrance compositions.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

2-Isobutyl thiazole naturally occurs in a variety of foods, most notably in green bell peppers, tomatoes, and other vegetables. It is formed through enzymatic reactions during the ripening of these vegetables. The compound is often used to enhance the "natural" flavor profile of food products, aligning with consumer preferences for natural ingredients.

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

4. Use in Flavors

2-Isobutyl thiazole is widely used in flavor formulations, particularly in savory applications such as soups, sauces, and snack foods. It serves as an impact note, providing a fresh, green, and slightly earthy character. 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 stable under typical processing conditions but may degrade under extreme heat or acidic conditions.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

In the fragrance industry, 2-isobutyl thiazole is used to impart a fresh, green note to compositions, often in conjunction with other green or herbal notes. It is commonly found in perfumes, air fresheners, and personal care products. The compound is typically used at low concentrations due to its high impact, contributing primarily to the top notes of a fragrance.

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 use in food flavors. In the European Union, it is regulated under Regulation (EC) No 1334/2008 and assigned FL No. 15.034. The compound is also approved for use in flavors in the United Kingdom, Japan, China, and several ASEAN countries. Regulatory status in Latin America, including Brazil and MERCOSUR countries, aligns with international standards, though specific approvals may vary.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

For oral exposure, 2-isobutyl thiazole is considered safe at typical use levels in food, with no specific ADI established. The compound is not known to cause irritation or sensitization upon dermal exposure, making it suitable for use in fragrances. Inhalation exposure is generally considered safe at typical fragrance concentrations, though occupational exposure limits should be observed in manufacturing settings. Overall, the risk profile is similar for both food and fragrance applications.

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 composition. Formulators should be cautious of its high impact, as overuse can lead to an overpowering or artificial aroma. It is often under-utilized in complex formulations where subtlety is required.

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 some variability exists in use levels and applications. No significant data gaps or regulatory ambiguities are noted.

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 2026-03-04 09:59:06 GMT (p2)