You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule (4aS,9bR)-6-butyl-8-(2,4,6-trichlorophenyl)-1,2,3,4,4a,9b-hexahydro-[1]benzofuro[3,2-c]pyridine .
user
C21H22Cl3NO
assistant