Theophylline as the sodjum salt (I) is reacted with chloroacetonitrile in dimethylformamide to give the nitrile (II). Treatment of (II) with hydroxylamine affords an amidoxime (III), which is acetylated to the O-acetyloxime (IV). The latter, when heated at 95 C in water buffered with triethylamine, cyclizes to Chinoin-170.