2-Propionylthiazole (CAS 43039-98-1) — Mid Note Fragrance Ingredient
2-Propionylthiazole
CAS 43039-98-1
What Is 2-Propionylthiazole?
2-Propionylthiazole (CAS 43039-98-1) is an aroma chemical used as a fragrance and flavour ingredient. Its odour is described as bakery, sweet and garlic, placing it within the gourmand family as a mid note with medium volatility. With a molecular weight of 141.2 (formula C6H7NOS), it is handled by perfumers as a building block for compositions where a bakery character is desired. The data below is compiled from public chemical and regulatory sources.
Safety Profile
HANDLE WITH CARE
What Does 2-Propionylthiazole Smell Like?
The odour profile of 2-Propionylthiazole is reported as bakery, sweet, garlic, spices, cold, sour, burnt, acid, warm, musky, sweaty, ammonia/urinous, decayed, wood, grass, flower, chemical, edible, fish, vegetable, nut. The dominant facet is its bakery character, with the remaining notes adding nuance and complexity. As a mid note it contributes to the heart of a fragrance. Perceived intensity and exact character depend on concentration, the carrier and the surrounding accord.
Scent Profile
Profile derived from public odour-descriptor data; relative, not absolute.
Chemistry & Properties
The Chemistry
2-Propionylthiazole has the molecular formula C6H7NOS and a molecular weight of 141.2 g/mol. Its canonical SMILES representation is CCC(=O)C1=NC=CS1. Its reported log P (XLogP) of 1.74 indicates a moderately polar molecule, which informs how it partitions in a formula. Physical constants below are drawn from PubChem and EPA CompTox public datasets.
Physical & Chemical Properties
| Molecular Weight | 141.2 g/mol |
|---|---|
| Boiling Point | 210.4 °C |
| Melting Point | 22.67 °C |
| Flash Point | 74.23 °C |
| Density | 1.21 g/cm³ |
| Vapor Pressure | 0.0836 mmHg |
| Water Solubility | 0.048 g/L |
| XLogP | 1.74 |
Perfumer Guide
Alternatives & Comparisons
Ingredients occupying a similar odour space — useful as substitutes or companions when 2-Propionylthiazole is unavailable or restricted.
Shares bakery, sweet, fish character — a candidate substitute or companion in the same odour space.
Shares bakery, sweet, fish character — a candidate substitute or companion in the same odour space.
Shares bakery, sweet, fish character — a candidate substitute or companion in the same odour space.
Safety & Regulatory
⚠ Regulatory Disclaimer
General reference only. IFRA, REACH and EU Cosmetics Regulation standards update periodically. Consult the current IFRA Standards Library before formulating. Not legal or regulatory advice.
IFRA Status
No IFRA restriction recorded in the data set. This is not a guarantee of unrestricted status — always confirm against the current IFRA Standards Library.
GHS Classification
Signal word: Warning
Open 2-Propionylthiazole in Fragrance Studio (Pro) for the calibrated vapour-pressure curve, the modelled odour-threshold estimate, and the substitute-matching engine across 2,900+ aromachemicals.
References & Sources
- PubChem Compound Summary (NIH) — search by InChIKey
- EPA CompTox Chemicals Dashboard — physicochemical & fate data
- IFRA Standards Library (49th / 51st Amendment)
Data: PubChem (NIH), EPA CompTox, IFRA. Last reviewed: Jun 2026.
Related Research
- Farnesal (CAS 19317-11-4) — Green Top to middle Note Fragrance Ingredient
- .Eta.-1H-Indol-1-yl-.alpha.,.alpha.,.epsilon.-trimethyl-1H-indole-1-heptanol (CAS 67801-36-9) — Musky Base Note Fragrance Ingredient
- Benzenepropanenitrile, 4-ethyl-.alpha.,.alpha.-dimethyl- (CAS 134123-93-6) — Woody Base Note Fragrance Ingredient
- Lavender oil (Lavandula dentata) (CAS 93165-50-5) — Floral Top to middle Note Fragrance Ingredient
