Yamamoto, Daisuke; Sunazuka, Toshiaki; Hirose, Tomoyasu; Kojima, Naoto; Kaji, Eisuke; Omura, Satoshi Bioorganic and Medicinal Chemistry Letters, 2006, vol. 16, # 10 p. 2807 - 2811 doi: 10.1016/j.bmcl.2006.01.107