Patent ID: 8501731

Claim:
A pyridazinone having the structure of formula I: wherein, R is —OH, —SH, substituted or unsubstituted C 6 -C 12 aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted C 3 -C 10 cyclic alkyl, substituted or unsubstituted heterocyclic group, —OR a , —NHR a , —NR a R b or —SR a , wherein R a and R b are independently selected from the group consisting of substituted or unsubstituted C 1 -C 10 alkyl, substituted or unsubstituted C 3 -C 10 cyclic alkyl, substituted or unsubstituted C 6 -C 12 aryl, substituted or unsubstituted heteroaryl, and substituted or unsubstituted heterocyclic group; the substituents are selected from the group consisting of halogen, —OH, —NO 2 , C 1 -C 6 alkyl, carboxyl, C 1 -C 6 alkoxyl carbonyl, C 6 -C 12 aryl, —NH 2 , C 1 -C 6 alkyl substituted amino, hydroxyl substituted C 1 -C 6 alkyl, hydroxyl substituted C 1 -C 6 alkoxyl group, unsubstituted or C 1 -C 6 alkyl substituted heterocyclic group, and —CF 3 ; the heteroaryl is 5- or 6-membered cyclic ring containing 1 to 3 heteroatoms selected from the group consisting of N, O and S; the heterocyclic group is 3- to 7-membered monocyclic ring or 8-membered bicyclic ring which may contain 1 to 3 heteroatoms selected from the group consisting of N, O and S, and the heterocyclic group is optionally substituted with oxo group or sulfido group.