Sesquiterpene lactones ofPseudohandelia umbellifera
Flowerheads of P. umbillifera collected in May 1976 in the Dzhizak oblast in the budding flowering phase were extracted with chloroform. The concentrated extract was dissolved in ethanol and the solution was diluted with water to give a 60% ethanolic solution. After a day, the precipitate that had deposited was separated off. The combined lactones were extracted with benzene from the filtrate after it had been treated with petroleum ether (to eliminate essential oil). The mixture of substances isolated was separated by chromatography on a column of alumina (activity grade IV) in a ratio of i:i0.
Sesquiterpene lactones of Artemisia. Artecalin from A. californica and A. tripartita ssp. rupicola
Abstract Artecalin (I), a sesquiterpene lactone of the Santanolide group, has been found in Artemisia californica Less. (section Abrotanum) and in A. tripartita Gray ssp. rupicola Beetle (section Seriphidium). By removal of the elements of water, artecalin is converted into tuberiferin, a constituent of a plant of the tribe Cichorieae.
Determination des configurations par “dedoublement partiel”—III : Alcools steroides
Resume La methode de dedoublement partiel (1) a ete appliquee a des alcools steroides tres varies et elle permet de trouver avec la plus grande surete la configuration α ou β de l'hydroxyle pour toutes les positions examinees, exception faite des positions 2, 3 et 16 qui, en l'absence de substituants vicinaux, ne donnent lieu qu'a de faibles dedoublements. Plusieurs steroides modifies ont aussi ete examines.