You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Under IUPAC nomenclature, a molecule named 2-imidazo[1,2-a]pyridin-3-yl-1-[4-(3-methoxybenzoyl)piperazin-1-yl]ethanone is given. What is its corresponding molecular formula?
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C21H22N4O3
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