In short
2-Ethyl-3,5(6)-dimethylpyrazine is a mixture of two isomeric pyrazines with a nutty, roasted, cocoa and hazelnut odour. One formula source sells it as Cocoa Pyrazine.
What 2-Ethyl-3,5(6)-dimethylpyrazine smells like
ChemicalBook lists 2-ethyl-3,5-dimethylpyrazine as nutty, nut skin, hazelnut, peanut, chocolate and roasted, and Elan Chemical sells 2-ethyl-3,5(or 6)-dimethylpyrazine as a toasted-nut, chocolaty material. PubChem's substance records give CAS 55031-15-7 for the isomer mixture.
- Leading note
- Roasted nut
- Clear facets
- Cocoa
- Supporting facets
- Hazelnut
- Character
- Roasted, powerful
What makes 2-Ethyl-3,5(6)-dimethylpyrazine distinctive
Toasted nut with a chocolate edge — hazelnut, peanut and roasted notes in one pyrazine.
How 2-Ethyl-3,5(6)-dimethylpyrazine is used
Used in traces in cocoa, hazelnut, coffee and roasted gourmand notes.
Typical role: modifier (used in small amounts to change the character of a blend).
How 2-Ethyl-3,5(6)-dimethylpyrazine differs from similar materials
- 2-Methylbutanal
- 2-Methylbutanal is a volatile, malty cocoa aldehyde for the top; the pyrazine is roasted hazelnut and chocolate, heavier and longer-lasting.
- Filbertone
- Filbertone is the specific hazelnut, buttery and metallic; the pyrazine is roasted nut and chocolate in general.
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
Pyrazines are very powerful and are used highly diluted. The 3,5-isomer is reported to be far more potent than the 3,6-isomer.
Identity and classification
- Type
- Aroma chemical
- Origin
- Occurs in nature
- Odour family
- Gourmand
- Note position
- Top to heart note
- Physical form at room temperature
- Liquid
- Also known as
- 2-Ethyl-3(5 or 6)-dimethylpyrazine
- CAS number
- 55031-15-7
The CAS number was checked on 25 October 2026 against a PubChem substance record that gives it for this material. It is sold as a mixture of 2-ethyl-3,5- and 2-ethyl-3,6-dimethylpyrazine, which PubChem records as one substance. So no single formula, molecular weight or structure drawing is given.
Safety and compliance
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
-
Tetramethylpyrazine
Aroma chemical · Gourmand — musty, fermented, coffee
-
2,3,5-Trimethylpyrazine
Aroma chemical · Gourmand — roasted, nutty, cocoa, earthy
-
Cacao Absolute
Absolute · Gourmand — chocolate, cocoa, roasted, bitter
Used in formulas and accords
Used in 3 published formulas
2-Ethyl-3,5(6)-dimethylpyrazine is an ingredient in 2 perfume formulas and 1 accord in the Formula & Accord Library.
Community formulas
RUŌOD House Originals
Original compositions by RUŌOD House.
Further reading
Questions about 2-Ethyl-3,5(6)-dimethylpyrazine
Is 2-Ethyl-3,5(6)-dimethylpyrazine natural or synthetic?
The molecule occurs in nature. Commercial 2-Ethyl-3,5(6)-dimethylpyrazine may be made by synthesis or obtained from natural sources, so check the supplier's specification if the distinction matters to you.
What is the CAS number of 2-Ethyl-3,5(6)-dimethylpyrazine?
55031-15-7, the registry number for the aroma chemical as a substance rather than a single molecule. It was checked against PubChem on 25 October 2026.
Which published formulas use 2-Ethyl-3,5(6)-dimethylpyrazine?
2-Ethyl-3,5(6)-dimethylpyrazine is used in 3 published formulas in the RUŌOD Lab Formula & Accord Library: Chocolate Accord, Patchouli Cold Brew and Praline Smoke. Each is listed with a link under "Used in formulas and accords" on this page.
Sources
- PubChem — substance 204409975, checked 25 October 2026.
- ChemicalBook — 2-Ethyl-3,5-dimethylpyrazine — odour database.
- Elan Chemical — 2-ethyl-3,5 (or 6)-dimethyl pyrazine (Knowde) — manufacturer's description.
- PubChem — Pyrazine, 2(or 3)-ethyl-3,5(or 2,5)-dimethyl- (substance) — 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.