2-Ethyl-4-methylthiazole

What 2-Ethyl-4-methylthiazole smells like

JECFA, as published by PubChem, describes 2-ethyl-4-methylthiazole as a colourless to pale yellow liquid with a nutty, green odour. Sigma-Aldrich gives green and nutty as its organoleptic profile, and Perflavory lists Bedoukian's and Treatt's descriptions as nutty, green and pistachio; PubChem links it to no natural-product database.

Leading note

Nutty

Clear facets

Green

• nutty
• green

What makes 2-Ethyl-4-methylthiazole distinctive

A thiazole that carries nuts and fresh green at once.

How 2-Ethyl-4-methylthiazole is used

Used in traces in nutty, roasted and green-vegetable effects.

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

How 2-Ethyl-4-methylthiazole differs from similar materials

2-Isopropyl-4-methylthiazole

Tropical thiazole is green, herbaceous and earthy; 2-ethyl-4-methylthiazole is described as nutty and green.

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

Potent; usually handled diluted.

Identity and classification

Type

Aroma chemical

Origin

Synthetic

Odour family

Gourmand / Green

Note position

Heart note

Physical form at room temperature

Liquid

CAS number

15679-12-6

Molecular formula

C6H9NS

Molecular weight

127.21 g/mol

IUPAC name

2-ethyl-4-methyl-1,3-thiazole

The CAS number, formula and molecular weight are taken from PubChem compound 27440, 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 classify it (1,600 reports): H302 harmful if swallowed (97.1% of 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

• 2,3,5-Trimethylpyrazine

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

• Sulfurol

  Aroma chemical · Gourmand — beefy, nutty

• 2-Isopropyl-4-methylthiazole

  Aroma chemical · Green / Fruity — green, herbaceous, vegetable, earthy

Used in formulas and accords

Used in 3 published formulas

2-Ethyl-4-methylthiazole is an ingredient in 1 perfume formula, 1 accord and 1 base in the Formula & Accord Library.

Community formulas

• Hazelnut Accord

  Community Formula · Accord · listed as “2 Ethyl 4 Methyl Thiazole”

• Pistachio Base

  Community Formula · Base · listed as “2-Ethyl-4-Methyl Thiazole 1%”, at 1%

RUŌOD House Originals

Original compositions by RUŌOD House.

• Green Pod Theory

  RUŌOD House Creation · listed as “2-Ethyl-4-methylthiazole 1% DPG”, at 1% in DPG

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-Ethyl-4-methylthiazole

Sources

• PubChem — compound 27440, checked 24 October 2026.
• PubChem — GHS classification (the ECHA C&L Inventory notifications and any harmonised EU entry), read 26 October 2026.
• PubChem — 2-Ethyl-4-methyl thiazole (CID 27440): JECFA organoleptic description — odour database.
• Sigma-Aldrich — 2-ethyl-4-methylthiazole (W368008) — manufacturer's description.
• Perflavory — 2-ethyl-4-methyl thiazole — odour database.
• 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.