You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule 1-(4-bromophenyl)-2-(4-methoxy-6,6-dimethyl-7,8-dihydro-5H-[1,3]dioxolo[4,5-g]isoquinolin-6-ium-5-yl)ethanone .
user
C21H23BrNO4+
assistant