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 7-chloro-5-(2-chloroacetyl)-3,8-dimethoxy-2-(4-methoxyphenyl)-2,3-dihydro-1,5-benzothiazepin-4-one .
user
C20H19Cl2NO5S
assistant