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 5,6-dihydro-4H-cyclopenta[b]thiophen-2-yl-[5-(7H-pyrrolo[2,3-d]pyrimidin-4-yl)-5,8-diazaspiro[2.6]nonan-8-yl]methanone .
user
C21H23N5OS
assistant