You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the molecule identified by 1-O-methyl 3-O-[(2R)-1-oxo-1-(4-propan-2-ylanilino)propan-2-yl] 5-nitrobenzene-1,3-dicarboxylate ?
user
C21H22N2O7
assistant