1. V. N. Shibaev, Yu. Yu. Kusov, Sh. Kuchar, and N. K. Kochetkov, Izv. Akad. Nauk SSSR, Ser. Khim., 1973, 430.
2. P. Biely and ?. Bauer, Collection Czech. Chem. Commun.,32, 1588 (1967).
3. Yu. Yu. Kusov and V. N. Shibaev, Usp. Biol. Khim.,12, 182 (1971).
4. W. A. Bonner, J. Org. Chem.,26, 910 (1961).
5. D. L. MacDonald, J. Org. Chem.,27, 1107 (1962).