ISSN:
0170-2041
Schlagwort(e):
(+)-Cyclosarkomycin
;
Catalpol
;
Iridoids
;
Chemistry
;
Organic Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
Chemistry and Stereochemistry of Iridoids, XVIII. - Enantiomerically Pure (+)-Cyclosarkomycin from CatalpolThe reaction of hexaacetylcatalpol (2) with peroxyformic acid results in hexaacetyl-3-formyloxy-4-hydroxycatalpol (3), which is cleaved to 4 and sorbit (4a) by reduction with LiAlH4. The mixture of 4/4a was acetylated and the resulting acetates 5/5a separated by column chromatography. The following reactions from 5 to 9 (reactions e - i of Scheme 1) are each nearly quantitative. Therefore, the isolation of the intermediates 6-8 was not necessary. The constitutions of 6-8 were proven by 13C-NMR spectroscopy. The (1S,2RS,5R)-2-hydroxy-3-oxabicyclo[3.3.0]octan-6-one (9) was purified by column chromatography and its oxidation by pyridinium chlorochromate (PCC) in dichloromethane leads to crystalline (+)-cyclosarkomycin (10) [yield 85%, based on 5].
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/jlac.1992199201202
