Harada, Hiroshi; Hirokawa, Yoshimi; Suzuki, Kenji; Hiyama, Yoichi; Oue, Mayumi; Kawashima, Hitoshi; Yoshida, Naoyuki; Furutani, Yasuji; Kato, Shiro Bioorganic and Medicinal Chemistry Letters, 2003 , vol. 13, # 7 p. 1301 - 1305