You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the compound with this IUPAC name 2-[1-(5-ethyl-1,3,4-oxadiazol-2-yl)ethylsulfanyl]-3-prop-2-enylthieno[2,3-d]pyrimidin-4-one ?
user
C15H16N4O2S2
assistant