You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
methyl 2-[2-[(6-bromo-4-oxo-2-propylquinazolin-3-yl)iminomethyl]-6-nitrophenoxy]acetate The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H19BrN4O6
assistant