Pyrazine

Chemical properties

white crystals or powder

Chemical properties

Pyrazine has a strong pyridine-like odor. Some reports compare the taste of pyrazine to cooked spinach or rancid peanuts

Occurrence

Pyrazine has been detected in several food products including papayas, asparagus, peanuts, popcorn, soybeans, corn, French fries, bread, cheese, milk, eggs (boiled), chicken (fried), beef (cooked), shrimp, clams, beer, sherry, malt, coffee and tea (green).

The Uses of Pyrazine

Pyrazine is used as a flavoring agent. It serves as a component of some herbs in traditional Chinese medicine. It is employed as pharmaceutical intermediates, perfume intermediates and involved in the preparation of other chemicals. In addition to this, it is used in the production of pyrazine 1-oxide.

Definition

ChEBI: A diazine that is benzene in which the carbon atoms at positions 1 and 4 have been replaced by nitrogen atoms.

Definition

A heterocyclic aromatic compound with a six-membered ring containing four carbon atoms and two nitrogen atoms.

Definition

pyrazine: An unsaturated heterocycliccompound having two nitrogenatoms in a six-membered ring,C₄H₄N₂; r.d. 1.03; m.p. 52°C; b.p.115°C. Pyrazine is a symmetric diazine.

Preparation

Prepared by cyclization of α-amino ketones, which were produced by the reduction of isonitroso ketones to yield the dihydropyrazines, which are dehydrogenated with mercury(I) oxide or copper(II) sulfate or sometimes with atmospheric oxygen.

Aroma threshold values

300 ppm (odor threshold in water)

General Description

Pyrazine is a 1,4-diazine and an electron-deficient N-heteroarene found in several natural products, APIs, agrochemicals, and functional materials.

Purification Methods

Distil pyrazine in steam and crystallise it from water. Purify also by zone melting. [Beilstein 23 H 91, 23 II 80, 23 III/IV 899, 23/5 V 351.]