1H-Pyrano(3',4':6,7)indolizino(1,2-b)quinoline-3,14(4H,12H)-dione, 4-ethyl-4-hydroxy-9-nitro- 4-Ethyl-4-hydroxy-9-nitro-1H-pyrano(3',4':6,7)indolizino(1,2-b)quinoline-3,14(4H,12H)-dione 9-NC 9-Nitrocamptothecin 91421-42-0 9NC Camptogen Nitrocamptothecin Orathecin RFS 2000 Rubitecan Rubitecan [USAN]