Pyridazines. Part 22: Highly efficient synthesis of pharmacologically useful 4-cyano-6-phenyl-5-substituted-3(2H)-pyridazinones

A cyano group was directly and efficiently attached at the 4-position of the heterocyclic ring of 5-substituted-6-phenyl-3(2H)-pyridazinones using a practical and mild procedure. This direct cyanide addition offers a novel and one-pot approach to the synthesis of pharmacologically useful 4,5-difunctionalized-6-phenyl-3(2H)-pyridazinones.