Rearrangement of 2-methylpropanoic acid, 2-phenylhydrazide (I) provides 1,3-dihydro-3,3-dimethyl-2H-indol-2-one (II). Friedel Crafts' acylation of (II) with succinic anhydride in an aluminum chloride/DMF melt results in the formation of 4-oxobutanoic acid (III). Cyclization of (III) with hydrazine in refluxing ethanol completes the preparation of LY-195115.