When taken at the appropriate time and place, biorenewable leaves of the abundant Himalayan yew, Taxus wallichiana Zucc., contain significant quantities (0.045-0.130%) of taxol and other useful taxanes including 10-deacetylbaccatin III and brevifoliol. Spectroscopic reexamination of brevifoliol indicates that its structure must be revised to 11. This makes brevifoliol and recently reported taxchinin A (12) close molecular relatives.
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Acknowledgements: The authors thank Dr. William P. Duncan of Oread Laboratories for financial support and encouragementa nd Dr. Anand Burman of Dabur Industries, Inc., for provision of bulk supplies of Tars extracts. We also thank Dr. Kenneth Snader, NCI, for arranging for confirmatory biiassays and provfdtng authentic samples. Assistance with early collections by Dr. S. Ft. Vadapalli, Hyderabad, was very helpful. Ms. Wanda Waugh and Professor Valentino Stetla, Kansas University, provided outstanding analytical support in the earty phases of this work. Professor Fuji kindly sent us reference samples and a detailed manuscript prior to publication. We also gratefully acknowledge partial support of this work in the form of NIH grant CA 52790 and a grant from the lnez W. Jay Research Fund at Kansas University.