SEARCH Articles Figures Tables 2- Hydrazino-3-hydroxy-5,6-diphenylpyrazine 2- Hydroxy-3-isobutyl-5,6-diphenylpyrazine 2-Bromo-3-hydroxy-5,6-diphenylpyrazine 2-Carboxy-3-hydroxy-5,6-diphenylpyrazine 2-Chloro-3-hydroxy-5,6-diphenylpyrazine 2-Chloro-3-hydroxy-5,6-diphenylpyrazine with phosphoryl chloride 2-Hydroxy-3-methoxy-5,6-diphenylpyrazine 2-Hydroxy-3-nitro-5,6-diphenylpyrazine 2.3- Diphenylpyrazine 3- Hydroxy-2,5-diphenylpyrazine methylation 3- Hydroxy-2,5-diphenylpyrazine nitration