You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
tert-butyl 3-[6-(7-methoxyheptoxy)spiro[2H-1-benzofuran-3,4'-piperidine]-1'-yl]propanoate is the IUPAC name of a molecule. Please give its molecular formula.
user
C27H43NO5
assistant