You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule benzyl (2S)-2-methyl-5-oxo-5-[(1R,4R)-3-oxo-2-oxa-5-azabicyclo[2.2.1]heptan-5-yl]pentanoate .
user
C18H21NO5
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