A series of genistein derivatives was prepared and tested in vitro against leukocythemia (HL-60), colorectal adenocarcinoma (HT-29), and human gastric adenocarcinoma (SGC-7901) cell lines. Among these derivatives, 4′,5-di-n-octoxy-7-gem-difluoromethylenegenistein, 9f, had the strongest activity against HL-60, HT-29, and SGC-7901 cells.[Figure not avai...