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 cyclopentyl-[4-[[3-(2-methoxyethyl)-1,2,4-oxadiazol-5-yl]methyl]-1-oxa-9-azaspiro[5.5]undecan-9-yl]methanone .
user
C21H33N3O4
assistant