You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Name the molecular formula for the molecule established as N-[1,6-dihydroxy-4-[(E)-3-oxo-3-phenylprop-1-enyl]cyclohexa-2,4-dien-1-yl]-4-nitrobenzenesulfonamide using the IUPAC nomenclature.
user
C21H18N2O7S
assistant