2-Hydroxy-5,6-dimethyl-3-phenylpyrazine

Dimethylamino-7V-hydroxy-2-pyrazinecarboxamide 6-Dimethylamino-7V-hydroxy-2-pyrazinecarboxamidine 2-Dimethylamino-5-iodopyrazine 2-Dimethylamino-6-iodopyrazine 2-Dimethylamino-5-iodopyrazine 4-oxide 2-Dimethylamino-3-isobutylpyrazine 2-Dimethylamino-6-isobutylpyrazine 2-Dimethylamino-5-methoxy-3,6-dimethylpyrazine 2-Dimethylaminomethyl-3,6-bismethylthiopyrazine 2-Dimethylamino-6-methyl-5-phenylpyrazine 4-oxide 2-Dimethylamino-3-methylpyrazine 2-Dimethylamino-6-methylpyrazine 2-Dimethylamino-3-methylpyrazine 4-oxide Dimethyl 5-amino-6-oxo-1,6-dihydro-2,3-pyrazinedicarboxylate 2-Dimethylamino-5-phenylpyrazine 2-(3-Dimethylaminopropyl)-6-methylpyrazine... 

Dichloropyrazines have also been prepared from the corresponding hydroxy compounds as follows 2,3-dihydroxypyrazine with phosphoryl chloride containing pyridine (481, 757) [see Schneller and May (828) re the use of phenylphosphonic dichloride at 150-170°] 2,3-dihydroxypyrazine and its methyl, dimethyl, phenyl, diphenyl, and 5-methy 1-6-phenyl derivatives with phosphoryl chloride (483, 829) [N.B. error in work of Minovici and Bente (830)] 2-chloro-5-hydroxypyrazine with phosphoryl chloride (831) 2-chloro-6-hydroxypyrazine with phosphoryl chloride at reflux for 6hours (832) and 2,5-dihydroxy-3-phenylpyrazine and3,5-dihydroxy-2-phenylpyrazine with phosphoryl chloride at 180-200° (829). 

A 2-amino-5-substituted-pyrazine refluxed with p-toluenethiol, 2-methoxy-ethanol, and 2-amino-6-formyl-4-hydroxypteridine followed by heating with acetic anhydride gave the 2-amino-4-hydroxy-6-[A -(5 -substituted-pyrazin-2 -yl)-acetamidomethyl]pteridine (34) (1244). 2-Amino-5-phenylpyrazine with isobutyral-dehyde in ether at room temperature gave 2-(3-isopropyl-6, 6-dimethyl-5, 6-dihydro-l, 2, 4 -trioxin-5 -yl)aniino-5-phenylpyrazine (35) (1245). 

Hydroxy-5-nitro-3-phenylpyrazine with phosphoryl chloride at reflux gave 2-chloro-5-nitro-3-phenylpyrazine but at 170° gave 2,5-dichloro-3-phenylpyrazine (817). Phenylhydroxynitropyrazines are claimed not to react with dimethyl sulfate in alkaline solution or with sodium ethoxide and ethyl iodide in hot ethanol (817). 

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