Otsuki, Satsuki; Nishimura, Shinichi; Takabatake, Hisae; Nakajima, Kozue; Takasu, Yasuaki; Yagura, Toru; Sakai, Yuki; Hattori, Akira; Kakeya, Hideaki Bioorganic and Medicinal Chemistry Letters, 2013 , vol. 23, # 6 p. 1608 - 1611