5-ethoxy-3,6-dihydro-2H-1,4-oxazine

3,5,6,8-tetrahydro-2H-imidazo[2,1-c][1,4]oxazine

4-(4-溴苯基)吗啉-3-酮

1,1-dimethylethyl 3-oxo-4-morpholinecarboxylate