Aminolysis of Nuclear Halogenopyrazines

2-Chloropyrazine (69) gave 2-hydrazinopyrazine (68, R = NH2) (neat H2NNH2.H20, reflux, 40 min then 4°C, 2 days 70% 593 or H2NNH2, EtOH, reflux, 4 h 65%).622 

2-Chloropyrazine (69) and phenothiazine gave 10-(pyrazin-2-yl)phenothiazine (71) (KI, K2C03, Cu, no solvent, 240°C, 4 days 80%).1316 

6- Dichloropyrazine (73, X = Cl) gave 2-chloro-6-hydroxyaminopyrazine (72) (H2NOH, EtOH, reflux, 2 h 35%).1121 

6- Diiodopyrazine (73, X = I) gave 2-dimethylamino-6-iodopyrazine (74) (Me2NH, MeOH, reflux, 1 h 89%).638 

6- Dibromopyrazine (73, X = Br) and ethyl 3-pyrazolecarboxylate gave 2,6-bis(3-ethoxycarbonylpyrazol-l-yl)pyrazine (75) [K, THF then substrate J, reflux, 2 days 60%, after separation from 2-bromo-6-(3-ethoxycarbonylpyra-zol-l-yl)pyrazine (7%)].963 

6-Tetrachloropyrazine (78) gave 2,5-dichloro-3,6-diphthalimidopyrazine (79) (K-phthalimide, Me2NCHO, 50°C, 16 h %), and thence 3,6-dichloro- 

2-Chloro- (81, R = Cl) gave 2-hydrazino-3-(2-methylthioethyl)-5-phenylpyra-zine (81, R = NllNll, ) (55% ll. NNll, H2O, BuOH, reflux, 4 h 92%). 5 

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