You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule 4-oxo-4-(3-oxo-2,4-dihydroquinoxalin-1-yl)-N-[1-(4-propan-2-ylphenyl)ethyl]butanamide into molecular formula.
user
C23H27N3O3
assistant