5-Chloro-2-methoxy-3-methoxycarbonylpyrazine

Diazotization of 2-amino-3-alkoxycarbonylpyrazine foDowed by treatment with alcohols gave 2-alkoxy-3-alkoxycarbonylpyrazines (890) and 2-amino-5with methanol formed 5-chloro-2-methoxy-3-methoxycarbonylpyrazine (799,892). 

Methoxypyrazines (31) have been prepared by diazomethane methylation of 2-hydroxy-3-isobutylpyrazine (60, 311, 367), 2-hydroxy-3-isopropylpyrazine (59, 367), 2-hydroxy-3-propyl(ethyl or hexyl)pyrazine (367), 3-hydroxy-2-isobutyl-5(and 6)methylpyrazine and 2-hydroxy-3-isobutyl-5,6-dimethylpyrazine (368), 2,3-dihydroxypyrazine (832), 2-hydroxy-5-methoxy- and 2,5-dihydroxy-3,6-diphenyl-pyrazine (832), 2-hydroxy-6-methoxy(and benzyloxy)pyrazine (832), 2,6-dihydroxy-3,5-diphenylpyrazine (873), 2,3,5-trifluoro-6-hydroxypyrazine (851), 2-chloro-6-hydroxy-3,5-diphenylpyrazine (873), 2-chloro-6-hydroxy-5-methyl-3-phenylpyrazine (873), 2-chloro-6-hydroxy-3-methyl-5-phenylpyrazine (873), 5,6-dichloro-1 -cyclohexyl-34iydroxy-2-oxo-l, 2-dihydropyrazine (853), 2-chloro-5-hydroxy-3-methoxy-6-methoxycarbonylpyrazine (881), 2-(4 -amino-3, 5 -dibromo-phenylsulfonamido)-3Tiydroxy-6-methoxypyrazine (881), 2-amino-3-hydroxy-... 

Amino-3-methoxycarbonylpyrazine with urea in the presence of sodium hydride in dimethylformamide at — 15° gave 2-amino-3-ureidocarbonylpyrazine (1152, 1322). The reaction was also applied to the following pyrazines 2-amino-5-chloro-3-methoxy carbonyl (1152) 2,6-diamino-3-chloro-5-methoxycarbonyl (1380) 2-amino-5-chloro-3-methoxycarbonyl-6-methylamino (1380) 2-amino-5-chloro-6-dimethylamino(and other dialkylamino)-3-methoxycarbonyl (1152) and 2-amino-5-chloro-3-methoxycarbonyl-6-methylthio (1152). The preparation of ureidocarbonylpyrazines from A -cyanamides has been described in Section 2C(2)(d). 

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