Hirose, Tomoyasu; Sunazuka, Toshiaki; Zhi-Ming, Tian; Handa, Masaki; Uchida, Ryuji; Shiomi, Kazuro; Harigaya, Yoshihiro; Omura, Satoshi Heterocycles, 2000 , vol. 53, # 4 p. 777 - 784