Toba, Tetsuya; Murata, Kenji; Nakanishi, Kyoko; Takahashi, Bitoku; Takemoto, Naohiro; Akabane, Minako; Nakatsuka, Takashi; Imajo, Seiichi; Yamamura, Takashi; Miyake, Sachiko; Annoura, Hirokazu Bioorganic and Medicinal Chemistry Letters, 2007, vol. 17, # 10 p. 2781 - 2784 doi: 10.1016/j.bmcl.2007.02.081