You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance 3-[2-(3,4-dihydro-1H-isoquinolin-2-yl)-2-oxoethyl]-1-hept-6-enyl-1,2-dimethylguanidine .
user
C21H32N4O
assistant