1. (a) Heterocycles in Natural Product Synthesis; Majumdar, K. C.; Chattopadhyay, S. K., Eds.; Wiley-VCH: Weinheim, 2011. (b) The Chemistry of Heterocyclic Compounds; Coppola, G. M.; Schuster, H. F.; Wiley: New York, 1981, Vol. 38, Part 3, p. 552.
2. Merck, G. Ann. Chem. Pharm. 1848, 66, 125.
3. Saunders, R. N. J. Pharmacol. Exp. Ther. 1988, 247, 617. (b) Houlihan, W. J.
4. Larson, D. A. J. Med. Chem. 1993, 36, 3098. (c) Scholz, D.
5. Baumruker, T. J. Med. Chem. 1998, 41, 1050. (d) Griffin, R. J.