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system
Name the molecular formula for the molecule established as 9-(3-chloro-4-methoxyphenyl)-3-ethyl-1,7-dimethyl-4a,6,7,8-tetrahydropurino[7,8-a]pyrimidin-5-ium-2,4-dione using the IUPAC nomenclature.
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C19H23ClN5O3+
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