A series of derivatives with various oxygen functionalities in positions 17,22a or 19,20 was prepared from diene I and olefin XVI by addition and oxidation reactions. The structure of the obtained compounds was confirmed by 1 H NMR, 13 C NMR and IR spectroscopy. The kind of intramolecular association of the 17α-hydroxy group was studied in connection with modification of the side chain and substitution in position 22a. Complete assignment of the hydrogen signals and most of the coupling constants was accomplished using a combination of 1D and 2D NMR techniques. The 1 H and 13 C NMR spectra are discussed.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

A series of epimeric pairs of 20R and 20S acetylamino derivatives VIII-XI have been prepared by reduction and subsequent acetylation of the oximes I, III, IV and VI. Their absolute configuration at C-20 (20R and 20S for the series a and b, respectively) has been suggested on the basis of their physical and spectral properties. The correctness of this assignment was confirmed by the synthesis of the acetylamino derivatives Xa and Xb from the acids XIIa and XIIb, respectively, with known configuration at C-20.

The structure of anhydrobetulin II and its derivatives, I, III and IV has been solved using H-1 and C-13 NMR spectra, mass spectra and chemical transformations. It has been proven that in addition reactions the trisubstituted double bond is attacked selectively from the alpha-side under formation of D/E cis-annelated derivatives VIII, X and XI. The 22-oxo derivative XIII exhibits an anomalous Cotton effect and, in contrast to its saturated analogue XXVII, it is not epimerized in alkaline medium. Trinordiketone XXI easily epimerizes to a mixture in which the 17-beta-H-epimer XXIb predominates, trinorketone XXIV is stable only if the annelation of rings D and E is trans. These differences are explained in terms of steric interactions of substituents in position 19. The steric course of reduction of ketones XIII and XXIV with sodium borohydride is described.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The structure of anhydrobetulin II and its derivatives I, III and IV has been solved using 1H and 13C NMR spectra, mass spectra and chemical transformations. It has been proven that in addition reactions the trisubstituted double bond is attacked selectively from the α-side under formation of D/E cis-annelated derivatives VIII, X and XI. The 22-oxo derivative XIII exhibits an anomalous Cotton effect and, in contrast to its saturated analogue XXVII,it is not epimerized in alkaline medium. Trinordiketone XXI easily epimerizes to a mixture in which the 17βH-epimer XXIb predominates, trinorketone XXIV is stable only if the annelation of rings D and E is trans. These differences are explained in terms of steric interactions of substituents in position 19. The steric course of reduction of ketones XIII and XXIV with sodium borohydride is described.

19β,28-Epoxy-18α-oleanane derivatives I-III were converted into hydroxy ketones IV, VIII and X , acetoxy ketones V, VII, IX and XI , diols and their mono- and diacetates XII-XXV . Seven of the eight possible isomeric 2,3-diol monoacetates were obtained. Conformation of the ring A in these compounds has been derived from the 1 H NMR and IR spectra. In 2β-acetoxy-3-ketone VII , 3α-hydroxy- and 3α-acetoxy-2-ketones VIII and IX , and in 2β,3α-diol monoacetates XVIII and XIX the ring A exists predominantly in a boat conformation.

Reactions of 2α,3α-epoxide X, derived from 19β,28-epoxy-A(1)-nor-18α-oleanane, with acids proceed with migration of the 10β-methyl group into the position 2β, giving rise to unsaturated alcohols XII and XIV and diene IX. Reaction with boron trifluoride etherate afforded ketone XI in addition to XII and XIV. Olefin VIII rearranged in acidic medium to give olefins XXVI and XXVII. The rearranged products were converted into other derivatives and their structure was established by 1H and 13C NMR, IR, UV and mass spectra.

AbstractThe photolysis of the epoxyoleanol nitrite (I) affords the oximes (II) and (III) by functionalization of the 10β‐methyl group as well as of the rather distant 8β‐methyl group.

On photolysis, 19β,28-epoxy-18α-oleanan-2β-ol nitrite (I) undergoes functionalization of the 10β-methyl group (formation of oxime II) as well as of the rather distant 8β-methyl group (leading to oxime III). No products of attack at the 4β-methyl group have been found. The 2β-nitrolyloxy-3β-acetoxy derivative XX reacts similarly whereas its 2β-nitrosyloxy-3α-acetoxy isomer XIII is photolyzed to give diol XI. Oximes II and III were converted into two series of nitriles (a and b) with various functional groups on the ring A. Structure of all compounds was derived from their spectral data. Double radical transfer has been proposed for functionalization of the 8β-methyl group (position 26).

Ethylene dithioketals in positions 1, 2 and 3 of 19β,28-epoxy-18α-oleanane were prepared and reduced with deuterated Raney-nickel. The mass spectra of dithioketals and corresponding 1,1-, 2,2- and 3,3-dideuterio derivatives were studied and discussed with the possibility of localizing the functional group in the A ring.

AbstractThe title compounds (IV) can successfully be prepared starting from ketone (I).

Lupane triterpenoids are attacked by peroxyacetic acid in position 19. 3β,28-Lupanediol diacetate (I) affords the 18β,19β-epoxy derivative III and the 19β-hydroxy derivative V, lupane (II) gives 18β,19β-epoxylupane (IV); however, the yields are low. Structure of the products III and IV was confirmed by independent preparation from the 20(29)-unsaturated compounds IX and X.

AbstractThe title reaction of the ketone (I) yields the products (IV)‐(VI) via Baeyer‐Villiger oxidation or the hydroxy ketone (VII) depending on the concentration of H2SO4.

19β,28-Epoxy-18α-oleanan-3-one (I), 19β,28-epoxy-24-nor-18α-oleanan-3-one (XIV) and 3-lupanone (XVII) are hydroxylated with 3-chloroperoxybenzoic acid in the presence of methanol or ethanol and 0.01-0.1% of sulfuric acid in position 2α. Hydroxy ketones VII, XV, and XVI are formed, respectively. The reaction is sensitive to the concentration of sulfuric acid; beyond this concentration range predominantly various 3,4-seco derivatives are formed (for example VI, IX, X, XVIII). 2-Oxo derivative IV is hydroxylated in a similar manner, giving rise to 3α-hydroxy-2-ketone VIII, while 1-oxo derivative XIII does not react. A reaction path is proposed for the hydroxylation, comprising the enol form or the enol ether as an intermediate.