1. T. F. Spand, M. W. Edwards, J. W. Daly, J. Am. Chem. Soc., 1992, 114, 3475.
2. G. A. Tolstikov, V. M. Dembitskii, T. G. Tolstikova, E. E. Shul´ts, Izbrannye metody sinteza i modifikatsii geterotsiklov [Selected Methods for Synthesis and Modification of Heterocycles], Ed. V. G. Kartsev, IBS PRESS, Moscow, 2003, V. 1, p. 418 (in Russian).
3. J. Cheng, Sh. Chen, D. Paul, M. L. Trudell, J. Med. Chem., 2002, 45, 3041.
4. J. V. Braun, K. Schwarz, J. Liebigs Ann. Chem., 1930, 56, 481.
5. R. C. Menziel, R. Robinson, J. Chem. Soc., 1924, 2163.