You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance methyl (3S)-3-[6-[(4-formylpiperazin-1-yl)methyl]-3-hydroxy-4-oxopyran-2-yl]-3-(4-hydroxyphenyl)propanoate .
user
C21H24N2O7
assistant