Nuclear and Extranuclear C-Alkylation

2-Aminopyrazine was alkylated with ethyl methyl ketone and sodium in liquid ammonia (in the absence of a catalyst) to 2-amino-6-butylpyrazine, and a similar reaction occurred with isobutyraldehyde (614) and 2-cyano-3-(A, A -dimethylamino-methyleneamino)-5-methylpyrazine was deprotonated with lithium diisopropyl-amide (from butyllithium and diisopropylamine) and alkylated with ethyl iodide followed by removal of the protecting group by acid hydrolysis to give 3-amino-2-cyano-5-propylpyrazine (1031). 

2-NHj-3- imidazol-2 yl) MeCCOEt), 6-Methy limidazo[ 1,2-c )(pteridine) 455a 

2-NHCH=NOH l N—N (L) s-Triazolo l,5-a]pyrazine Polyphosphoric acid Unsubstituted 1234 

The reactions of 2-(3 -dimethylaminopropyl)pyrazine with sodium amide in liquid ammonia and aliphatic, aromatic, and heterocyclic esters to give ketones have been described in Section IV.2A(3) (645), and with ketones to give carbinols in Section IV.2C(5) (707). 

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Nuclear and extranuclear C-alkylation has been discussed in detail in Sections 2A(2) and 2A(3), respectively. 

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