You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Convert the IUPAC name of a molecule ethyl 5-(4-chlorophenyl)-2-[(1-ethylpyrazol-4-yl)methylidene]-7-methyl-3-oxo-5H-[1,3]thiazolo[3,2-a]pyrimidine-6-carboxylate into molecular formula.
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C22H21ClN4O3S
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