Synthesis of some 5H-imidazo[4,5-e]-as-triazin-6-(7H)ones (6-azapurin-8-ones)

Treatment of 1,3-dialkyl-7-azalumazine derivatives with alcoholic sodium hydroxide caused a benzylic acid type rearrangement followed by decarboxylation and oxidation by air to give the corresponding 5,7-dialkyl-5H-imidazo[4,5-e]-as-triazin-6-(7H)ones (7,9-dialkyl-6-azapurin-8-ones).