Synthesis of novel acyclonucleosides. Reactions of 1‐(2‐oxopropyl)pyridazin‐6‐ones

Multi‐substituted‐1‐(1‐bromo‐2‐oxopropyl)pyridazin‐6‐ones 3, 4 , multi‐substituted‐1‐(1,1‐dibromo‐2‐oxopropyl)pyridazin‐6‐ones 7, 8 , and multi‐substituted‐1‐(3‐bromo‐2‐oxopropyl)pyridazin‐6‐ones 5, 6 were synthesized from the corresponding 1‐(2‐oxopropyl)pyridazin‐6‐ones 1, 2 by the selective bromination in acidic or neutral medium. And treatment of 1,1‐dibromo‐2‐oxopropyl derivatives 7, 8 with aqueous potassium carbonate gave the corresponding pyridazin‐6‐ones 9, 10 by the dealkylation. Reaction of 1 with methanolic potassium cyanide afforded only the corresponding 4‐methoxy derivative 11 , whereas reaction of 2 with methanolic potassium cyanide gave 4‐methoxy derivative 12 and 2‐cyano‐2‐hydroxypropyl derivative 13 . Reaction of 1 and 2 with hydroxylamine in methanol afforded the corresponding syn‐2‐hydroxyiminopropyl derivatives 14 and 15 .