Miscellaneous Displacement Reactions of Nuclear Halogenopyrazines

Several little-used but potentially useful displacement reactions are typified in the following examples  

2-Chloro-3,6-dimethylpyrazine (192) gave methyl 3,6-dimethyl-2-pyrazinecar-boxylate (193) CO (40 kg/cm2), MeOH, Et3N, Pd[PhCH=CHC (=0)CH=CHPh]2, Ph3P, 150°C, autoclave, 16 h 85%, 224, cf-1222 

2-Chloropyrazine (194, R = Cl) gave a separable mixture of /V,/V-diethyl-2-pyrazinecarboxamide (194, R = CONEt2) and 2-diethylaminopyrazine (194, R = NEt2) (as in preceding example but Et2NH, 120°C 85 and 8%, respec- 

2-Chloropyrazine gave 2-bis(trilluoromethyl)aminooxypyrazine (195) Hg-[ON(CF3)2]2 (made in situ), C12FCCC1F2 (solvent), 50°C, sealed, 3 days 22%. 1319 

6-Dichloropyrazine gave 2-chloro-6-[m-methoxy-a, a-(trimethylenedithio)-benzyl]pyrazine (196), the acetal of an acylpyrazine [2-(m-methoxyphenyl)-1,3-dithiane anion (made in situ), 2-Me—THF, -100 — 20°C 14%].1482 2-Chloropyrazine gave several Ni or Pd complexes.566,581 Also other examples.374,882 

6-Dichloropyrazine gave 2-chloro-6-[m-methoxy-a, a-(trimethylenedithio)-benzyllpyrazine (196), the acetal of an acylpyrazine [2-(z//-methoxyphenyl)- 

---