5-ethoxy-1,4-oxazepine

3-Oxo-2-azabicyclo[2.2.0]hex-5-ene

2-(tert-butyldimethylsilyl)-2-azabicyclo[2.2.0]hex-5-en-3-one

6-(tert-butyldimethylsilyl)-6-aza-3-oxatricyclo[3.2.0.02,4]heptan-7-one

2-羟基吡啶