Description
2-Methylpyrazine has an odor threshold in water variously
reported at 60,000 or 105,000 ppb. May be prepared from the
corresponding carboxylic acid; by catalytic dehydrogenation of
2-methyl-piperazine; by condensation of methylglyoxal with ethylenediamine.
Chemical Properties
clear colorless to slightly yellow liquid
Chemical Properties
2-Methylpyrazine has a nutty, cocoa, green, roasted, chocolate, meaty odor.
Occurrence
Reported found in bakery products, roasted barley, cocoa products, coffee, dairy products, cooked meats,
peanuts, filberts, pecans, popcorn, potato chips, rum and whiskey, soy product, roasted filberts, roasted almonds, guava, papaya,
asparagus, kohlrabi, baked and fried potato, milk, boiled egg, smoked fish, beer, coffee, sesame seed, rice, sukiyaki, buckwheat,
sweet corn, corn tortillas, malt, wort, wild rice, okra, crayfish, clam, squid and maté.
Uses
2-Methylpyrazine is used as flavoring agents in bread fresh bread, butter, chocolate, chocolate cocoa, coffee, meat roasted, nut almond.
Uses
These Secondary Standards are qualified as Certified Reference Materials. These are suitable for use in several analytical applications including but not limited to pharma release testing, pharma method development for qualitative and quantitative analyses, food and beverage quality control testing, and other calibration requirements.
Preparation
From corresponding carboxylic acid; by catalytic dehydrogenation of 2-methyl-piperazine; by condensation of methylglyoxal with ethylenediamine
Definition
ChEBI: Methylpyrazine is a member of the class of pyrazines that is pyrazine in which one of the hydrogens is replaced by a methyl group. It is a flavouring agent found in coffee, peanuts and red peppers. It has a role as a flavouring agent, a plant metabolite and a Maillard reaction product.
Aroma threshold values
Detection: 60 ppb to 100 ppm
Taste threshold values
Taste characteristics at 75 ppm: nutty, brown, musty, roasted and astringent
General Description
2-Methylpyrazine is an alkyl-substituted pyrazine used as a key intermediate in the synthesis of pyrazineamide, an anti-tubercular drug.
Safety Profile
Moderately toxic by
ingestion and intraperitoneal routes.
Mutation data reported. Flammable liquid
when exposed to heat, sparks, or flame. Can react with oxidizing materials. To fight fire,
use water spray, foam, dry chemical, CO2.
When heated to decomposition it emits
highly toxic fumes of NOx.
Synthesis
2-Methylpyrazine is mostly synthesized via cyclization of ethylenediamine (ED) and 1,2-propylene glycol (PG)
[1].
Purification Methods
Purify it via the picrate and distil the free base. The picrate has m133-134o(from EtOH). [Wiggins & Wise J Chem Soc 4780 1956, Beilstein 23 III/IV 911, 23/5 V 386.]
References
[1] Hou, J., Luo, Wen., Luo, S., Lin, C., Liu, P., Liao, X., Jing, F., & Li, X. (2017). Facile synthesis of CuMAl (M = Cr, Mn, Zn, and Co) with highly dispersed Cu and tailorable surface acidity for efficient 2-methylpyrazine synthesis. RSC Advances, 77, 48662–48669.
https://doi.org/10.1039/C7RA08349A
