You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
magnesium;7-[(3-bromophenyl)methyl]-1,3-dimethyl-2,6-dioxopurine-8-carbaldehyde;7-[(3-bromophenyl)methyl]-1,3-dimethyl-8-pentanoylpurine-2,6-dione;7-[(3-bromophenyl)methyl]-8-(hydroxymethyl)-1,3-dimethylpurine-2,6-dione;7-[(3-bromophenyl)methyl]-8-(1-hydroxypentyl)-1,3-dimethylpurine-2,6-dione;butane;dichloromethane;oxolane;chloride is the IUPAC name of a molecule. Please give its molecular formula.
user
C78H93Br4Cl5MgN16O13
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