N-{8-[({3-[(4R)-6,8-dichloro-2-methyl-1,2,3,4-tetrahydroisoquinolin-4-yl]phenyl}dioxo-λ6-sulfanyl)amino]-3,6-dioxaoct-1-yl}-1-({8-[({3-[(4S)-6,8-dichloro-2-methyl-1,2,3,4-tetrahydroisoquinolin-4-yl]phenyl}dioxo-λ6-sulfanyl)amino]-3,6-dioxaoct-1-yl}amino)methanamide