Pyrazines physical properties

Table 3 lists some of the basic physical properties of pyrazine, quinoxaline and phenazine (references are given in the main text). 

Table 3 Physical Properties of Pyrazine, Quinoxaline and Phenazine...

An extensive table by Brown of boiling points and melting points of simple pyrazines described up to the end of 2000, together with reported spectra or other physical properties, is available. 

This chapter covers the preparations, physical properties, and reactions of pyrazine and its C-alkyl, C-aryl,. V-alkyl, or A/ -aryI derivatives as well as their respective di-, tetra-, and hexahydro derivatives (the last usually known as piperazines). In addition, it includes methods for introducing alkyl or aryl groups (substituted or otherwise) into pyrazines and hydropyrazines already bearing substituents and the reactions specific to the alkyl or aryl groups in such products. For simplicity, the term alkylpyrazine in this chapter is intended to include alkyl-, alkenyl-, alkynyl-, cycloalkyl-, and aralkylpyrazines likewise, the term arylpyrazine includes both aryl- and heteroarylpyrazines. 

This table is intended as a comprehensive alphabetical list of simple pyrazines described up to the end of 2000. For each compound are recorded (1) melting and/or boiling point(s) (2) an indication of reported spectra or other physical properties (3) any reported salts or simple derivatives, especially when the parent compound was un- or ill-characterized (4) an indication of any complexes reported and (5) direct reference(s) to the original literature from 1978 onward, preceded by any page(s) in parentheses, for example, (H 440), on which earlier published data have been reported in Barlin s Hauptwerk,1686... 

Quantification of the pyrazines was accomplished using an internal standard metlxxd. 2-methoaypyrazine was chosai as internal standard due to its similar physical properties (HW, solubility) to the pyrazines of interest and because methosypyrazines have never been reported to form as a result of the Maillard reaction. Ihe amounts of each pyrazine presoit in the sample were determined by the relationship ... 

TABLE V.3 PHYSICAL PROPERTIES OF SIMPLE HALOGENO-PYRAZINES"... 

Pyrazolo[3,4-fe]pyrazines have been the subject of a variety of reports dealing mainly with the synthesis and physical properties of the ring system. 

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