4,5-Dimethyl-2-isobutylthiazole

What 4,5-Dimethyl-2-isobutylthiazole smells like

JECFA, as published by PubChem, describes 4,5-dimethyl-2-isobutylthiazole as a colourless to pale yellow liquid with an earthy, nutty, green vegetative aroma. PubChem lists geranium thiazole among its synonyms. The Good Scents Company gives its odour type as green, of high strength, best smelled at 0.1%, and lists geranium, green, rose, nutty, vegetable, earthy and beany notes.

Leading note

Green earthy

Supporting facets

Nutty, vegetable

• earthy
• nutty
• green
• vegetable

What makes 4,5-Dimethyl-2-isobutylthiazole distinctive

An earthy, leafy thiazole, green in the way crushed leaves are.

How 4,5-Dimethyl-2-isobutylthiazole is used

JECFA evaluates it as a flavouring agent, and The Good Scents Company rates its odour as high in strength, best smelled at 0.1%. In perfumery it is a trace modifier for green, geranium-leaf and earthy-vegetable effects, used from dilution.

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

How 4,5-Dimethyl-2-isobutylthiazole differs from similar materials

2-Isopropyl-4-methylthiazole

2-Isopropyl-4-methylthiazole is green, nutty and fruity, sold for tropical fruit; geranium thiazole is earthier and leafier, with a geranium-green note.

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

Green / Gourmand

Note position

Heart note

Physical form at room temperature

Liquid

Also known as

Geranium thiazole, 2-Isobutyl-4,5-dimethylthiazole

CAS number

53498-32-1

Molecular formula

C9H15NS

Molecular weight

169.29 g/mol

IUPAC name

4,5-dimethyl-2-(2-methylpropyl)-1,3-thiazole

The CAS number, formula and molecular weight are taken from PubChem compound 104513, 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 (120 reports): H302 harmful if swallowed (65.8% of reports); H315 causes skin irritation (12.5% of reports); H319 causes serious eye irritation (12.5% of reports); H335 may cause respiratory irritation (12.5% of reports). 25 of the reports find it does not meet the hazard criteria. 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-Isopropyl-4-methylthiazole

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

• Geranium Oil

  Essential oil · Floral / Green — rosy, green, minty, fresh

• cis-3-Hexenol

  Aroma chemical · Green / Fruity — green, cut grass, leafy, fresh

Used in formulas and accords

Used in 2 published formulas

4,5-Dimethyl-2-isobutylthiazole is an ingredient in 1 perfume formula and 1 accord in the Formula & Accord Library.

Community formulas

• Ivy Accord

  Community Formula · Accord · listed as “Geranium Thiazole 1%”, at 1%

RUŌOD House Originals

Original compositions by RUŌOD House.

• Green Pod Theory

  RUŌOD House Creation · listed as “4,5-Dimethyl-2-isobutylthiazole 1% DPG”, at 1% in DPG

Further reading

• Green Notes in Perfumery: Leaf, Galbanum and Violet Leaf

  The green palette — cis-3-hexenol, galbanum, violet leaf, styrallyl acetate — what green notes do, dosage, restrictions and pairings.

Questions about 4,5-Dimethyl-2-isobutylthiazole

Sources

• PubChem — compound 104513, checked 24 October 2026.
• PubChem — GHS classification (the ECHA C&L Inventory notifications and any harmonised EU entry), read 26 October 2026.
• PubChem — 4,5-Dimethyl-2-isobutylthiazole (CID 104513): JECFA organoleptic description — odour database.
• The Good Scents Company — 4,5-dimethyl-2-isobutyl 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.