2-Iodo-5-phenylpyrazine

Iodo-3-methyl-2-pyrazinamine 2-Iodo-3-methylpyrazine 2-Iodo-5-phenylpyrazine 2-Iodo-3-phenylthiopyrazine... 

This convenient indirect process involves conversion of a pyrazinone into the conesponding trimethylsiloxypyrazine, and thence (with phosphorus halide) into the required halogenopyrazine. For example, 5-phenyl-2(lH)-pyrazinone afforded crude 2-phenyl-5-trimethylsiloxypyrazme (neat McsSiNHSiMe , ClSiMc, reflux, 30 min) that reacted with an appropriate phosphorus halide to furnish 2-bromo-(neat PBrj, 150 (1 1 h 77% overall), 2-chloro- (neat PCI5, 2(X) C. 1 h 40%), or 2-iodo-5-phenylpyrazine (PI3, CI2CHCH2CI, reflux, 24 h 12%) homologues were made similarly. ... 

Bromo-3-methoxycarbonylpyrazine with 2,3-dimethylaniline in refluxing toluene gave 2-(2, 3 -dimethylphenyl)amino-3-methoxycarbonylpyrazine (950) [hydrolysis of this product with sodium hydroxide in ethanol gave 2-carboxy-3-(2, 3 -dimethylphenyl)aminopyrazine, which was also obtained by treatment of l-(2, 3 -dimethylphenyl)lumazine with sodium hydroxide in refluxing ethanol (950)]. 3-Bromo-2-hydroxy-5-phenylpyrazine with ammonium hydroxide and copper at 150° gave 3-amino-2-hydroxy-5-phenylpyrazine (365a). Replacement of the iodo substituent from 2-amino-5-iodo-3,6-dimethylpyrazine has been effected with ammonium hydroxide (887). 

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