You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-butyl-5,6-dimethyl-2-[3-(4-propan-2-ylpiperazin-1-yl)propylsulfanyl]thieno[2,3-d]pyrimidin-4-one The above is the IUPAC name of a molecule. Write its molecular formula.
user
C22H36N4OS2
assistant