Hypolipidemic activity of phthalimide derivatives. 7. Structure-activity studies of indazolone analogues.

The apparent benefit of limiting serum cholesterol and triglyceride levels either by dietary restriction or drug therapy has prompted work in our laboratories toward development of a suitable antihyperlipidemic agent. We have demonstrated the antihyperlipidemic activity of a series of phthalimide derivatives in rodents to be significantly greater than that of clofibrate at a dose of 20 mg/(kg day), intraperitoneally. Here we report the synthesis and biological evaluation of a series of indazolone derivatives, which are heterocycles that are structurally related to the phthalimides . In general, structure-activity relationships within the phthalimide series may be extended to the indazolones . While indazolone itself is only moderately active, N1-carbethoxy substitution produced a more active compound. Substitution of the N2 position with an n-butyl group afforded the most active compound, as also seen in the phthalimide series. Aromatic substitution with electron-releasing and -withdrawing groups lessened the antihyperlipidemic activity.