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 7-[(N-ethyl-4-fluoroanilino)methyl]-2-methyl-3-(pyrrolidin-1-ylmethyl)-[1,3]thiazolo[3,2-a]pyrimidin-5-one .
user
C21H25FN4OS
assistant