Pyrazines. Part IV. 2,6-Dihydroxy-3,5-diphenylpyrazine and related compounds

Abstract

2,6-Dihydroxy-3,5-diphenylpyrazine was prepared by treatment of 1-hydroxy-3,5-diphenylpyrazin-2-one (Ia) with a mixture of acetic anhydride and acetic acid, followed by deacetylation of the resulting 2,6-diacetoxy-3,5-diphenyl-pyrazine with potassium hydrogen carbonate in methanol. The reaction of the hydroxypyrazinone with phosphoryl chloride gave 2-chloro-6-hydroxy-3,5-diphenylpyrazine. The 1-hydroxy-5(or 3)-methyl-3(or 5)-phenylpyrazinones (Ib and c) underwent similar reactions with phosphoryl chloride, but with acetic anhydride no ring-substituted products were isolated.