1. should like to express my special gratitude to Professor for his helpful discussions REFERENCES This volume page;Dunitz;Pure Appl Chem
2. in press;Keller;Chim Acta,1970
3. a;Pioda;Analytical Letters Chimia,1969
4. a also article Colloquium der Gesellschaftfür Biologische Chemie Mosbach;Stefanac;Chimia Review,1966
5. article Progress in the Chemistry of Organic Natural Products;Keller;Review,1964