3-羟基-1H-吲哚-2-羧酸乙酯

diethyl 4-oxo-1-phenylazetidine-2,2-dicarboxylate

Diethyl (2-chloro-N-phenylacetamido)malonate

ethyl 1-methyl-2,5-dioxo-3-phenylimidazolidine-4-carboxylate

ethyl 2,5-dioxo-1,3-diphenylimidazolidine-4-carboxylate