You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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(4E)-1-butyl-4-[(4-chloro-2,5-dimethoxyphenyl)-hydroxymethylidene]-5-pyridin-2-ylpyrrolidine-2,3-dione is the IUPAC name of a molecule. Please give its molecular formula.
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C22H23ClN2O5
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