ethyl 3-(3,3-dimethyl-2-oxoazetidin-1-yl)but-2-enoate

4-methyl-6H-pyrano[3,2-c]quinoline-2,5-dione

ethyl 3-methyl-5-(phenylcarbamoylamino)-1,2-thiazole-4-carboxylate

triethyl 5-methyl-1H-pyrrole-2,3,4-tricarboxylate

ethyl 3-acetamidobutanoate