1. (a) Sezaki, M.; Hara, T.; Ayukawa, S.; Takeuchi, T.; Okami, Y.; Hamada, M.; Nagatsu, T.; Umezawa, H. J. Antibiot. 1968, 21, 91. Nagatsu, T.; Ayukawa, S.; Umezawa, H. J. Antibiot. 1968, 21, 91.
2. (b) Sezaki, M.; Kondo, S.; Maeda, K.; Umezawa, H.; Ohno, M. Tetrahedron 1970, 26, 5171.
3. Also, see: (c) Imamura, N.; Kakinuma, K.; Ikekawa, N.; Tanaka, H.; Omura, S. Chem. Pharm. Bull. 1981, 29, 1788.
4. For reviews on the angucycline antibiotics, see: Rohr, J.; Thiericke, R. Nat. Prod. Rep. 1992, 103. Krohn, K.; Rohr, J. Top. Curr. Chem. 1997, 188, 127.
5. (a) Total syntheses of angucyclines possessing the C-glycoside (urdamycinone B): Yamaguchi, M.; Okuma, T.; Horiguchi, A.; Ikeura, C.; Minami, T. J. Org. Chem. 1992, 57, 1647. Sulikowski, G. A.; Boyd, V. A. J. Am. Chem. Soc. 1995, 117, 8472. Matsuo, G.; Miki, Y.; Nakata, M.; Matsumura, S.; Tashima, K. Chem. Commun. 1996, 224. (C104): Matsumoto, T.; Sohma, T.; Yamaguchi, H.; Kurata, S.; Suzuki, K. Synlett 1995, 263. Matsumoto, T.; Sohma, T.; Yamaguchi, H.; Kurata, S.; Suzuki, K. Tetrahedron 1995, 51, 7347.