Ursolic acid inSorbus aucuparia
chromatographed on A1203, a mixture of neutral substances was obtained with the absorption bands in the IR spectrum characteristic for anhydrides (1805, 1734, and 1000 cm" 1) [3], which disappeared after the saponification of this mixture with 0.5 N ethanolic KOH at 40" C (figure, b). Pure abietic acid was extracted from the saponification product. Under the conditions mentioned, esters of the resin acids (if they are present in the mixture) are not saponified and therefore the acid was produced by the saponification of the anhydride.
Triterpene, IX. Über die Triterpene aus der Rinde von Sambucus nigra L. und die Darstellung von 3-epi-Ursolsäure
Die Isolierung von Ursolsaure (als Methylester), Betulin, α-Amyrin, β-Sitosterin, Cerylalkohol und n-Heptacosan aus der Rinde von S. nigra L. sowie die Darstellung von 3-epi-Ursolsaure und einigen Derivaten werden beschrieben.
Highly enantio- and diastereoselective synthesis of β-methyl-γ-monofluoromethyl-substituted alcohols.
Enanatiopure β-methyl-γ-monofluoromethyl alcohols were prepared from the allylic alkylation between fluorobis(phenylsulfonyl)methane with Morita-Baylis-Hillman carbonates. The reaction was catalyzed by using the Cinchona alkaloid derivative, (DHQD)(2)AQN. The origin of the stereoselectivity was verified by DFT methods. Calculated geometries and relative energies of various transition states strongly support the observed stereoselectivity.