Shimamura, Tadashi; Shibata, Jun; Kurihara, Hideki; Mita, Takashi; Otsuki, Sachie; Sagara, Takeshi; Hirai, Hiroshi; Iwasawa, Yoshikazu Bioorganic and Medicinal Chemistry Letters, 2006 , vol. 16, # 14 p. 3751 - 3754