2,5-Dimethyl pyrazine Property

Melting point:

15°C

Boiling point:

155 °C (lit.)

Density 

0.99 g/mL at 25 °C (lit.)

refractive index 

n20/D 1.502(lit.)

FEMA 

3272 | 2,5-DIMETHYLPYRAZINE

Flash point:

147 °F

storage temp. 

Inert atmosphere,Room Temperature

solubility 

Chloroform (Slightly), DMSO (Slightly), Methanol (Slightly)

form 

Liquid

pka

2.21±0.10(Predicted)

Specific Gravity

0.990

color 

Clear colorless to pale yellow

PH

7 (H2O)

Odor

at 0.10 % in dipropylene glycol. nutty roasted baked potato

Odor Type

chocolate

Sensitive 

Hygroscopic

JECFA Number

766

BRN 

107052

Dielectric constant

2.4399999999999999

LogP

0.64

CAS DataBase Reference

123-32-0(CAS DataBase Reference)

NIST Chemistry Reference

Pyrazine, 2,5-dimethyl-(123-32-0)

EPA Substance Registry System

Pyrazine, 2,5-dimethyl- (123-32-0)

Safety

Hazard Codes 

Xn,Xi

Risk Statements 

22-36/37/38-R22

Safety Statements 

26-36

RIDADR 

NA 1993 / PGIII

WGK Germany 

3

RTECS 

UQ2800000

Hazard Note 

Irritant

TSCA 

Yes

HS Code 

29339990

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Warning

Hazard statements

H302Harmful if swallowed

2,5-Dimethyl pyrazine Chemical Properties,Usage,Production

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

Uses

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.

Uses

2,5-Dimethyl pyrazine is used for blending food, nuts and beverage flavors.

Application

2,5-Dimethyl pyrazine is held chiefly responsible for the typical flavor of Potato Chips (oil-fried, thin-sliced Potato). It has therefore been manufactured synthetically and is used in the reconditioning of commercial products, such as Potato Chips and the packaging material for same, and also for reconditioning of "instant" coffee.

Definition

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

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.

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.]