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 [2-[3-(3,4-dimethoxyphenyl)-5-thiophen-2-yl-3,4-dihydropyrazol-2-yl]-2-oxoethyl] (E)-but-2-enoate .
user
C21H22N2O5S
assistant