2-(4-methyl-6-oxo-2H-pyrano[2,3-c]pyrazol-3-yl)acetic acid

2-(1,4-dimethyl-6-oxopyrano[2,3-c]pyrazol-3-yl)acetic acid

ethyl 2-(2-methyl-3-oxo-1H-pyrazol-5-yl)acetate

ethyl 2-oxo-3-propan-2-ylcyclopentane-1-carboxylate

5-oxo-5-pyridin-4-ylpentanoic acid