Antitumor agents 292. Design, synthesis and pharmacological study of S- and O-substituted 7-mercapto- or hydroxy-coumarins and chromones as potent cytotoxic agents - Chen, Ying; Liu, Hong-Rui; Liu, Hong-Shan; Cheng, Ming; Xia, Peng; Qian, Keduo; Wu, Pei-Chi; Lai, Chin-Yu; Xia, Yi; Yang, Zheng-Yu; Morris-Natschke, Susan L.; Lee, Kuo-Hsiung (European Journal of Medicinal Chemistry, 2012)