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 (4S)-1-(5-chloro-2-methoxyphenyl)-4-[3-(3,4-dimethoxyphenyl)-1,2,4-oxadiazol-5-yl]pyrrolidin-2-one .
user
C21H20ClN3O5
assistant