PubMed · 2329677
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
T E Starzl, J J Fung. 1990-05-16. Transplantation.. https://pubmed.ncbi.nlm.nih.gov/2329677/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Explore the source record for details and available documents.
The size and positioning of substituents on a tetraene, along with the Woodward-Hoffmann rules, control the relative stereochemistry at the four adjacent chiral centers that are generated in the 8pi/6pi electrocyclization cascade. A biomimetic synthesis of (-)-SNF4435 C and (+)-SNF4435 D exploits these steric effects and allows confirmation of the predicted absolute stereochemistry of the natural products.
[reaction: see text] Two novel sulfur-containing analogs of the immunosuppressive natural product rapamycin (1) were obtained by feeding cultures of Streptomyces hygroscopicus with l-nipecotic acid (4) and either (S)-1,3-thiazane-4-carboxylic acid (5) or (S)-1,4-thiazane-3-carboxylic acid (6). The structures of the two new compounds, 20-thiarapamycin (2) and 15-deoxo-19-sulfoxylrapamycin (3), were determined by spectroscopic methods.