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-[1-(cyclopentanecarbonyl)piperidin-4-yl]-5,6,7,8-tetrahydro-3H-[1]benzothiolo[2,3-d]pyrimidin-4-one .
user
C21H27N3O2S
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