Description
Pyrazine is a heterocyclic aromatic organic compound and can be reacted to obtain diverse pyrazine derivatives. Pyrazines are important contributors to the flavor of various roasted, toasted, or similarly heated foods. Pyrazine derivatives exhibit a wide variety of aromas in food, e.g. 2-methoxy-3-isopropylpyrazine produces a green pea odor. Pyrazines and pyrazine derivatives are typically used as flavor agent. Pyrazines and Pyrazine derivatives are also used as fragrances.
References
[1] T.B. Adamsa, J. Doullb, V.J. Feronc, J.I. Goodmand, L.J. Marnette, I.C. Munrof, P.M. Newberneg, P.S. Portogheseh, R.L. Smithi, W.J. Waddellj and B.M. Wagnerk, The FEMA GRAS assessment of pyrazine derivatives used as flavor ingredients, Food and Chemical Toxicology, 2002, vol. 40, 429-451
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).
Uses
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.
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.
Definition
pyrazine: An unsaturated heterocycliccompound having two nitrogenatoms in a six-membered ring,C
4H
4N
2; r.d. 1.03; m.p. 52°C; b.p.115°C. Pyrazine is a symmetric diazine.
Definition
A heterocyclic aromatic compound with a six-membered ring containing four carbon atoms and two nitrogen
atoms.
Definition
ChEBI: A diazine that is benzene in which the carbon atoms at positions 1 and 4 have been replaced by nitrogen atoms.
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.]
