Pyrazinethiones alkylation

All the important routes to alkylthiopyrazines have been discussed already by primary synthesis (Chapters 1 and 2), by alkanethiolysis of halogenopyrazines (Sections 4.2.5 and 4.4), or by S-alkylation of pyrazinethiones (Section 6.1.2). The remaining minor routes are either unrepresented in recent literature or are illustrated in the following examples ... 

Pyrazinethiones (123) with alkyl halides in the presence of base produce pyrazinylthio compounds (124), which are easily oxidized with peroxymaleic acid to the sulfoxides (125). Cyanomethyl sulfoxide (125 = CN) is alkylated on the methylene carbon between the sulfoxide and cyano... 

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