Studies of Purine <i>N</i>-Oxides. III. The Synthesis of Purine 3-<i>N</i>-Oxides

Abstract

Abstract 6-Methoxy- and 6-ethoxypurine 3-N-oxides were obtained by the direct oxidation of the corresponding 6-alkoxypurines with hydrogen peroxide in aqueous acetic acid. 6-Chloropurine was oxidized with monoperphthalic acid in ether to give 6-chloropurine 3-N-oxide. These purine 3-N-oxides were then converted to hypoxanthine 3-N-oxide by hydrolysis with a sodium hydroxide solution. 6-Methoxypurine 3-N-oxide and hypoxanthine 3-N-oxide were identified with authentic samples unambiguously synthesized from 6-methylsulfonylpurine 3-N-oxide, which had itself been obtained by the oxidation of 6-methylthiopurine 3-N-oxide. The treatment of hypoxanthine 3-N-oxide with hydrochloric acid gave 6,8-dihydroxypurine, 8-chlorohypoxanthine, hypoxanthine, and 2-chloro-4-amino-5-imidazolecarboxamide.