1. A. Bischler and M. Lang, Chem. Ber.,28, 279 (1985).
2. W. L. F. Amarego, Adv. Heterocycl. Chem.,24, 1 (1979).
3. S. Johne and D. Groger, Pharmazie,25, 22 (1970).
4. C. K. Atal, Chemistry and Pharmacology of Vasicine — A New Oxytocic and Abortifacient, Regional Research Laboratory, Jammu-Tawi, New Delhi (1980).
5. S. Johne, in: The Alkaloids, Academic Press, New York, Vol. 29, A. Brossi (ed.) (1986), p. 99.