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 1-butyl-2-methyl-3-[6-[4-(3-methylbutanoyl)piperazin-1-yl]-6-oxohexyl]guanidine using the IUPAC nomenclature.
user
C21H41N5O2
assistant