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 2-[1-[4-[4-(4-hydroxypiperazin-1-yl)anilino]-5-oxo-6H-pyrimido[4,5-d]pyridazin-2-yl]piperidin-4-yl]acetonitrile using the IUPAC nomenclature.
user
C23H27N9O2
assistant