2-Propionyl-2-thiazoline

What 2-Propionyl-2-thiazoline smells like

JECFA, as published by PubChem, describes 2-propionyl-2-thiazoline as a colourless to light yellow liquid with a meaty, nutty, cooked, brown roasted aroma. Symrise gives roasted, popcorn, nutty and basmati rice as its descriptors, and a study of cysteine and sugar mixtures roasted in the laboratory, published by the institute now called Leibniz-LSB@TUM, identifies it as an intense roasty, popcorn-like odorant with a very low threshold.

Leading note

Roasted

Clear facets

Nutty

Supporting facets

Meaty, cooked

Character

Savoury

• roasted
• nutty
• meaty
• cooked

What makes 2-Propionyl-2-thiazoline distinctive

A brown, cooked-grain roast note with a savoury, meaty side.

How 2-Propionyl-2-thiazoline is used

Used in traces for roasted, popcorn and cooked-rice effects.

Typical role: modifier (used in small amounts to change the character of a blend).

How 2-Propionyl-2-thiazoline differs from similar materials

2-Acetylpyridine

2-Acetylpyridine is popcorn and roasted grain; 2-propionyl-2-thiazoline is described as meaty, nutty and brown-roasted.

Each difference compares the published descriptions of the two materials. Smell varies with grade, supplier and dilution; compare them side by side on blotters before substituting one for another.

Formulation considerations

Very potent; usually handled diluted.

Identity and classification

Type

Aroma chemical

Origin

Synthetic

Odour family

Gourmand

Note position

Heart note

Physical form at room temperature

Liquid

Also known as

2-Propionylthiazoline

CAS number

29926-42-9

Molecular formula

C6H9NOS

Molecular weight

143.21 g/mol

IUPAC name

1-(4,5-dihydro-1,3-thiazol-2-yl)propan-1-one

The CAS number, formula and molecular weight are taken from PubChem compound 6428990, whose own record lists this CAS number; checked 24 October 2026.

Safety and compliance

Hazard classification of the neat substance, as PubChem summarises it, read 26 October 2026. Companies notifying the ECHA C&L Inventory report it as not meeting the GHS hazard criteria (114 of 114 reports). Unless it is harmonised, this is the notifiers' own classification, not a binding one.

This page is general information, not a safety assessment or a specification. Confirm identity, composition, IFRA status and allergen content from your supplier's documents for the lot you hold.

Materials it works with

• 2-Acetylpyrazine

  Aroma chemical · Gourmand — popcorn, roasted, nutty, bready

• 2-Acetylpyridine

  Aroma chemical · Gourmand — popcorn, tobacco, fatty

• 2,3,5-Trimethylpyrazine

  Aroma chemical · Gourmand — roasted, nutty, cocoa, earthy

Used in formulas and accords

Used in 1 published formula

2-Propionyl-2-thiazoline is an ingredient in 1 accord in the Formula & Accord Library.

• Jasmine Rice Accord

  Community Formula · Accord · listed as “Basmatti Thiazoline 0.1%”, at 0.1%

Further reading

• Building a Gourmand Accord: Vanilla, Caramel and Beyond

  The materials of gourmand perfume — vanillin, ethyl maltol, coumarin, lactones, roasted notes — how to keep them wearable, and color and crystal problems.

Questions about 2-Propionyl-2-thiazoline

Sources

• PubChem — compound 6428990, checked 24 October 2026.
• PubChem — GHS classification (the ECHA C&L Inventory notifications and any harmonised EU entry), read 26 October 2026.
• PubChem — 2-Propionyl-2-thiazoline (CID 6428990): JECFA organoleptic description — odour database.
• Symrise — 2-Propionyl thiazoline 10% (product sheet) — manufacturer's description.
• Leibniz-LSB@TUM — Identification of key aroma compounds generated from cysteine and carbohydrates under roasting conditions — published literature.
• Olfactory profile: the RUŌOD Lab team's synthesis of the published descriptions above, reviewed 26 October 2026. Evidence: more than one published description. Classification and the short description: revision 1. Descriptions of odour are judgement, not measurement.