1. For pertinent references seeR. H. F. Manske,The Alkaloids (Academic Press, New York 1954), vol. IV, chapter 30.
2. T. A. Henry,The Plant Alkaloids (Blakiston, Philadelphia 1949), p. 306.
3. K. W. Bentley andH. M. E. Cardwell, J. chem. Soc.1955, 3252.
4. M. Shamma, Exper.16, 484 (1960).
5. R. S. Cahn, C. K. Ingold andV. Prelog, Exper.12, 81 (1956).