You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(4R)-3-[2-(3-methoxy-5-phenylphenyl)acetyl]-4-propan-2-yl-1,3-oxazolidin-2-one The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H23NO4
assistant