Stereochemical features of the structure of germacrane lactones and the applicability of Geissman's rule in this series

Autor:	G. P. Moiseeva, B. Kh. Abduazimov
Rok vydání:	1990
Předmět:	chemistry.chemical_classification Circular dichroism Series (mathematics) Double bond Chemistry Stereochemistry Plant Science General Chemistry Ring (chemistry) General Biochemistry Genetics and Molecular Biology Cotton effect Lactone
Zdroj:	Chemistry of Natural Compounds. 26:630-635
ISSN:	1573-8388 0009-3130
DOI:	10.1007/bf00630070
Popis:	Stereochemical features of the structure of the germacrane lactones have been investigated. By correlating the circular dichroism and the results of x-ray structural analyses of the germacranolides with different types of linkage of the lactone ring it has been estabished that Geissman's rule is satisfied in the trans-trans-germacral(10), 4-dienolide series if the lactone ring has the S-conformation and the decadiene ring the chair-chair conformation in the C6-trans-lactones and, correspondingly, the A and chair-chair conformations in the C6-cis compounds. The decadiene ring has the boat-boat conformation if there is an exocyclic double bond at C10 in the C8-trans-germacrolides, and a positive Cotton effect (CE) is observed in the CD spectra in the 220 nm region and a negative one at 200 nm.
Databáze:	OpenAIRE
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