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-[(2R)-1-(3,5-dimethylanilino)-4-methylsulfanyl-1-oxobutan-2-yl]-2-methoxybenzamide using the IUPAC nomenclature.
user
C21H26N2O3S
assistant