Synthesis of 4,5-functionalized-2-methyl-6-(substituted aryl)-3 (2H)-pyridazinones: a new group of potent platelet aggregation inhibitors.

A series of 4,5-functionalized-2-methyl-6-(substituted phenyl)-3 (2H)-pyridazinones were synthesized and evaluated as platelet aggregation inhibitors in human platelet rich plasma (PRP). The new products generally displayed significant higher activity with respect to the corresponding unsubstituted aryl compounds. Compounds 27 and 31 appeared of particular interest, being their IC50s in the submicromolar range. Structure-activity relationships (SARs) are discussed.