You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[(2Z)-2-[(2,3-dimethoxyphenyl)methylidene]-4-methyl-3-oxo-1-benzofuran-6-yl] 2-chloropropanoate is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H19ClO6
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