Study on oxazolopyrimidines. v. preparation of 9-substituted Hypoxanthines via 7-aminooxazolo[5,4-d]pyrimidines

Reaction of 4-cyano-5-ethoxymethylenaminooxazoles with aliphatic amines gave 7-alkylaminooxazolo[5,4-d]pyrimidines. The structure of these compounds was discussed on the basis of spectroscopic properties. These oxazolopyrimidines were converted to 9-alkylhypoxanthines by treatment with aqueous alkali (Method A) or by heating in formamide (Method B). Reaction of the ethoxymethylenamino compounds with aromatic amines gave 9-arylhypoxanthines directly (Method C).