Irinotecan Related Compound C – 11-Ethyl-4-hydroxy-4-methyl-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano[3′,4′:6,7]indolizino[1,2-b]quinoline-9-yl (1,4′-bipiperidine)- 1′-carboxylate hydrochloride