You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule 2-O-ethyl 6-O-methyl (5R)-3,7-dimethyl-5-(4-methylphenyl)-5H-[1,3]thiazolo[3,2-a]pyrimidine-2,6-dicarboxylate .
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C20H22N2O4S
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