2- Chloro-3-phenylpyrazine

Chloro-3-isobutylpyrazine 4-oxide gave 3-isobutyl-2( I // )-pyrazinone 4-oxide (111, R = Hu ) (5 M NaOH, reflux, 2 h 39%) 86 2-chloro-3-phenylpyrazine 4-oxide gave 3-phenyl-2( I //(-pyrazinone 4-oxide (111, R = Ph) (KOH, H20—EtOH, reflux, 1 h 30%) 1290 also analogues likewise.1290... 

Chloro-6-phenylpyrazine 2-Chloro-3-phenylpyrazine 1,4-dioxide 2-Chloro-5-phenylpyrazine 1,4-dioxide 2-Chloro-3-phenylpyrazine 1-oxide 2-Chloro-3-phenylpyrazine 4-oxide 2-Chloro-5-phenylpyrazine 1-oxide 2-Chloro-5-phenylpyrazine 4-oxide 2-Chloro-6-phenylpyrazine 1-oxide... 

Many chloropyrazines have been prepared from hydroxypyrazines by reaction with mixed phosphorus pentachloride-phosphoryl chloride as follows 2-hydroxy-pyrazine to 2-chloropyrazine (818), 2-hydroxy-3-phenylpyrazine to 2-chloro-3-phenylpyrazine (535), 2-hydroxy-6-methyl- and 5-hydroxy-23-[Pg.102]

Normal nucleophilic substitution reactions of alkyl and aryl chloropyrazines have been examined as follows 2-chloro-3-methyl- and 3-chloro-2,5-dimethyl(and diethyl)pyrazine with ammonia and various amines (535, 679, 680) 2-chloro-3(and 6)-methylpyrazine with methylamine and dimethylamine (681, 844), piperidine and other amines (681, 921) 2-chloro-5(and 6)-methylpyrazine with aqueous ammonia (362) alkyl (and phenyl) chloropyrazines with ammonium hydroxide at 200° (887) 2-chloro-3-methylpyrazine with aniline and substituted anilines (929), and piperazine at 140° (759) 2-chloro-3-methyl(and ethyl)pyrazine with piperidine (aqueous potassium hydroxide at reflux) (930,931) [cf. the formation of the 2,6-isomer( ) (932)] 2-chloro-3,6-dimethylpyrazine with benzylamine at 184-250° (benzaldehyde and 2-amino-3,6-dimethylpyrazine were also produced) (921) 2-chloro-3,5,6-trimethylpyrazine with aqueous ammonia and copper powder at 140-150° (933) and with dimethylamine at 180° for 3 days (934,935) 2-chloro-6-trifluoromethylpyrazine with piperazine in acetonitrile at reflux (759) 2-chloro-3-phenylpyrazine with aqueous ammonia at 200° (535) 2-chloro-5-phenylpyrazine with liquid ammonia in an autoclave at 170° (377) 2-chloro-5-phenylpyrazine with piperazine in refluxing butanol (759) but the 6-isomer in acetonitrile (759) 5-chloro-2,3-diphenylpyrazine and piperidine at reflux (741) and 5-chloro-23-diphenylpyrazine with 2-hydroxyethylamine in a sealed tube at 125° for 40 hours (834). 

The reactions of various chlorophenylpyrazines with potassium amide in liquid ammonia have been investigated in detail (827). Treatment of 2-chloro-3-phenylpyrazine with potassium amide in liquid ammonia gave only 2-amino-3-phenyl-pyrazine, but 2-chloro-6-phenylpyrazine gave 4(5)-phenylimidazole and 2-cyano-4(5)-phenylimidazole, and 2-chloro-5-phenylpyrazine gave a mixture of 2-amino-5-phenylpyrazine, 4(5)-phenylimidazole, and 2-cyano-4(5)-phenylimidazole. The 2[Pg.125]

Phenylpyrazine 4-oxide (52) gave a separable mixture of 2-chloro-3-phenylpyrazine (53), 2-chloro-5-phenylpyrazinc (54), and 2-chloro-... 

Chloro-3-isobutylpyrazine 4-oxide gave 3-isobutyl-2(l//)-pyrazinone 4-oxide (111, R = Bu ) (5 M NaOH, reflux, 2 h 39%) 2-chloro-3-phenylpyrazine... 

Chloro-3-phenylpyrazine, C-70142 2-Chloro-5-phenylpyrazine, C-70143 2-Chloro-6-phenylpyrazine, C-70144 2-Chloro-4-phenyIpyrimidine, C-80100 4-Chloro-2-phenylpyrimidine, C-80102 4-Chloro-5-phenylpyrimidine, C-80103... 

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