You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the molecule methyl (2R)-2-[[(4S)-4-(2,3-dimethoxyphenyl)-1,4,6,7-tetrahydroimidazo[4,5-c]pyridine-5-carbonyl]amino]-3-methylbutanoate ?
user
C21H28N4O5
assistant