Synthesis of Betulonic and Betulinic Acids from Betulin

Yakovleva, M. P.; Выдрина, В. А.; Sayakhov, R. R.; Ishmuratov, G. Yu.

doi:10.1007/s10600-018-2479-8

Cited by 8 publications

(3 citation statements)

References 9 publications

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“…The most common group of preparative methods for betulonic acid is the oxidation of betulin with hexavalent chromium compounds. We [19] previously proposed a new environmentally friendly synthetic approach to betulonic acid (1), which involves the consecutive oxidation of betulin with Swern reagent and with the NaClO…”

Section: Resultsmentioning

confidence: 99%

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Synthesis of [2+1] Conjugates of Betulic Acid with α,ω-Diols

et al. 2021

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Section: Resultsmentioning

confidence: 99%

“…), 42.42 (C14 ), 46.99 (CH18 ), 47.28 (C 4 ), 49.27 (CH19 ), 49.88 (CH 9 ), 54.89 (CH5), 56.44 (C 17 ), 63.10 (CH 2 10' ) 63.90 (CH 2 1' ), 109.60 (CH 2 29 ), 150.49 (C 20 ), 176.00 (C 28 ), 218.08 (C 3 ). Found, %: C 78.56; H 10.80; O 10.64.…”

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Synthesis of [2+1] Conjugates of Betulic Acid with α,ω-Diols

et al. 2021

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“…), manganese (two-stage Swern-type oxidation of betulin and then with a solution of KMnO 4 in a mixture 1,4-dioxane in water [ 33 ]), as well as mixtures of 2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPO) with NaClO 2 -NaOCl [ 34 ]. Moreover, the two-stage Swern-type oxidation of betulin, followed by the oxidizing system NaClO 2 , H 2 O 2 and NaH 2 PO 4 ·H 2 O in t -BuOH in water was reported [ 35 ]. Since these methods do not correspond to the principles of green chemistry, numerous efforts were focused on finding alternative ways to obtain oxo-derivatives of betulin.…”

Section: Introductionmentioning

confidence: 99%

Supported Silver Nanoparticles as Catalysts for Liquid-Phase Betulin Oxidation

et al. 2021

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Herein, it has been shown that betulin can be transformed into its biologically active oxo-derivatives (betulone, betulinic and betulonic aldehydes) by liquid-phase oxidation over supported silver catalysts under mild conditions. In order to identify the main factors determining the catalytic behavior of nanosilver catalysts in betulin oxidation, silver was deposited on various alumina supports (γ-alumina and boehmite) using deposition–precipitation with NaOH and incipient wetness impregnation methods, followed by treatment in H2 or O2. Silver catalysts and the corresponding supports were characterized by X-ray diffraction, nitrogen physisorption, inductively coupled plasma optical emission spectroscopy, photoelectron spectroscopy and transmission electron microscopy. It was found that the support nature, preparation and treatment methods predetermine not only the average Ag nanoparticles size and their distribution, but also the selectivity of betulin oxidation, and thereby, the catalytic behavior of Ag catalysts. In fact, the support nature had the most considerable effect. Betulin conversion, depending on the support, increased in the following order: Ag/boehmite < Ag/boehmite (calcined) < Ag/γ-alumina. However, in the same order, the share of side reactions catalyzed by strong Lewis acid centers of the support also increased. Poisoning of the latter by NaOH during catalysts preparation can reduce side reactions. Additionally, it was revealed that the betulin oxidation catalyzed by nanosilver catalysts is a structure-sensitive reaction.

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