Abstract A series of N-substituted 8-aminoxanthines (= 8-amino-3, 7 (or 3, 9)-dihydro-1H- purine-2, 6-diones) 8–16 and 34–37 were synthesized from the corresponding 8- nitroxanthines 1–7, 30–33, and 8-(phenylazo) xanthines 17 and 18 by catalytic reduction. Another approach was derived from 6-amino-5-(cyanoamino) uracils (= N-(6-amino-1, 2, 3, 4- tetrahydro-2, 4-dioxopyrimidin-5-yl) cyanamides) 23, 24, and 27 by base-catalyzed ...
