Halogenopyrazines extranuclear

Note There appear to be no recent examples of the direct thiolysis of extranuclear halogenopyrazines All such transformations have been done indirectly via an isothiouronium intermediate (cf. Section 4.2.4). 

Many such hydroxypyrazines have been made by primary synthesis (see Chapters 1 and 2), some by C- or N-hydroxyalkylation procedures (see Sections 3.1.1.1 and 3.2.2.1), and a few by hydrolysis of extranuclear halogenopyrazines (see Section 4.4). Other preparative routes are illustrated in the following classified examples ... 

Extranuclear hydroxypyrazines react as alcohols or phenols according to the type of substituent that bears the hydroxy group. Already covered are their conversion into alkenylpyrazines by dehydration (Section 3.2.1.5) or into extranuclear halogenopyrazines (Section 4.3.1). 

By aminolysis of halogenopyrazines (nuclear, extranuclear primary, secondary, tertiary, quaternary) Sections 4.2.1 and 4.4. 

Some preparations of extranuclear aminopyrazines from extranuclear halogenopyrazines and amines have been described in Section V.6B (542, 679, 932,1029-1031). 2-Chloromethylpyrazine also reacted with sodium azide and gave 2-azidomethylpyrazine, which was hydrogenated in 95% ethanol over Adams catalyst to 2-aminomethylpyrazine (690). 

Also other examples, suss.sos,1180,1195,1412,1518 gome using extranuclear halogenopyrazines as substrates. ... 

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