ethyl 6-oxa-2,2,4,4-tetramethyl-1-azabicyclo(3,1,0)hexane-3-carboxylate

diethyl 1,3,5-trimethylpyrrole-2,4-dicarboxylate

3-甲基-2-丁烯酸乙酯

ethyl ester of 3,3,5,5 -tetramethyl-pyrroline-carboxylic acid

ethyl 5-hydroxy-1,2,4,4-tetramethylpyrroline-3-carboxylate