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 8-ethyl-9-[2-hydroxy-2-(4-methylphenyl)ethyl]-2-pyrimidin-4-yl-7,8-dihydro-6H-pyrimido[1,2-a]pyrimidin-4-one .
user
C22H25N5O2
assistant