5-Bromo-2-hydroxy-3-phenylpyrazine

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). 

Amino-5-bromo-3-carbamoylpyrazine heated with trifluoroacetamide and sodium ethoxide (or butoxide) gave 6-ethoxy(or butoxy)-4-hydroxy-2-trifluoro-methylpteridine (49) (987) and 2-chloro-3-pyridiniopyrazine chloride with methoxide ion gave 2,3-dimethoxypyrazine (765). 2-Amino-3-bromo-5-phenyl-pyrazine with sodium methoxide in methanol at 134° for 8 hours formed 2-amino-3-methoxy-5-phenylpyrazine (365a) and 3-bromo-2-hydroxy-5-phenylpyrazine similarly treated gave 2-hydroxy-3-methoxy-5-phenylpyrazine (365a). 

Refluxing phosphoms tribromide converted 2-bromo-3-hydroxy-5,6-diphenyl-pyrazine and 2-bromo-5-hydroxy-3,6-diphenylpyrazine to the dibromopyrazines 2,3-dichloro-5,6-dimethylpyrazine and 2,5-dichloro-3-phenylpyrazine to the dibromopyrazines (817) 5-chloro-2,3-diphenylpyrazine (and its 6-ethyl derivative) to 5-bromo-2,3-diphenylpyrazine (and its 6-ethyl derivative) (866) and 2-hydroxy-... 

Section II.7 describes some ring closures of the C-C-N-C-C, N-C-C-N-C-C, and N-C-C-N-C-C-N systems to give hydroxypyrazines (248, 365a, 477, 479, 480-483) more information can be found in reference 1054. Newbold and Spring (89) described the reaction of 2-bromo-A -(r-methyl-2 -oxopropyl)propionamide with ethanolic ammonia to give 2-hydroxy-3,5,6-trimethylpyrazine and Masaki et al. (551) have described the reaction of A -leucyl-6>-benzyIhydroxylamine (2) with phenacyl bromide in methanol saturated with ammonia to give 3-hydroxy-2-isobutyl-5-phenylpyrazine and 2,5-diphenylpyrazine. 

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