You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[(5S)-2-(4-chloro-2,5-dimethoxyphenyl)imino-3-ethyl-4-oxo-1,3-thiazolidin-5-yl]-N-(2-nitrophenyl)acetamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H21ClN4O6S
assistant