Design and Synthesis of a Fluoroindolocarbazole Series as Selective Topoisomerase I Active Agents. Discovery of Water-Soluble 3,9-Difluoro-12,13-dihydro-13-[6-amino-β-d-glucopyranosyl]-5H,13H-benzo[b]thienyl[2,3-a]pyrrolo[3,4-c]carbazole-5,7(6H)-dione (BMS-251873) with Curative Antitumor Activity against Prostate Carcinoma Xenograft Tumor Model.