You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[7-[(5-chlorothiophen-2-yl)methyl]-1,3-dioxo-5,6,8,8a-tetrahydroimidazo[1,5-a]pyrazin-2-yl]-N-(2-methoxyethyl)acetamide;hydrochloride is the IUPAC name of a molecule. Please give its molecular formula.
user
C16H22Cl2N4O4S
assistant