2,5-Dimethyl pyrazine

Chemical properties

clear colorless to pale yellow liquid

Chemical properties

2,5-Dimethylpyrazine has a characteristic odor of earthy, potato-like odor.

Occurrence

Reported to be present in bakery products, roasted barley, cocoa products, roasted coffee, dairy products, pork, peanuts, pecans, filberts, popcorn, potato products, rum and whiskey, soy products; a volatile component in roasted filberts and in potato chips; reportedly identified in the fat of cooked beef; also reported found in toasted off-flavors. Also reported in cheeses, butter, boiled eggs, grilled beef, tea, barley, oats, oatmeal, soybeans, heated beans, kohlrabi, shrimp and mushrooms. Also reported found in coffee, potato chips and shrimp

The Uses of 2,5-Dimethyl pyrazine

2,5-Dimethylpyrazine is used as a reagent in the synthesis of bone-targeted proteasome inhibitors for multiple myeloma (MM). 2,5-Dimethylpyrazine is also used in the preparation of 3-Methyl-2,5-bis-(2-hydroxyethyl)pyrazine (M295340); a degredation product of Clavulanic Acid (C563750) which is a β-lactamase inhibitor, typically added to amoxicillin to increase its effectiveness.

Preparation

By the interaction of acrolein and ammonia when heated in glycerol in the presence of ammonium salts; by self-condensation of aminoacetone, followed by oxidation with mercury chloride.

Definition

ChEBI: 2,5-Dimethylpyrazine is a member of pyrazines.

Aroma threshold values

Detection: 80 ppb to 1.8 ppm

Taste threshold values

Taste characteristics at 7.5 ppm: musty, potato, cocoa and nutty with a fatty and oily nuance

General Description

2,5-Dimethylpyrazine is a pyrazine compound that is mainly formed in food products such as cooked rice or roasted peanuts due to the Maillard reaction between sugars and proteins during cooking or roasting process.

Safety Profile

Moderately toxic by ingestion and intraperitoneal routes. Mutation data reported. When heated to decomposition it emits toxic fumes of NOx

Purification Methods

Purify it via its picrate (m 150o) which is decomposed with a base (e,g, KOH) and distilled. [Wiggins and Wise J Chem Soc 4780 1956]. [Beilstein 23/5 V 403.]