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-[(2-chloro-5-nitrophenyl)methyl-methylamino]-3-methyl-1-oxobutan-2-yl]-2-methylbenzamide using the IUPAC nomenclature.
user
C21H24ClN3O4
assistant