A new synthesis of 3-oxo-28-hydroxylup-20(29)-ene from the available natural triterpenoid betulin was developed. α,ω-Diketodiesters were prepared for the first time by different methods from 3-oxo-28-hydroxylup-20(29)-ene and a series of natural dicarboxylic acids. Steglich reaction conditions gave the highest yields. One of the synthesized α,ω-diketodiesters was moderately active in vitro against A-549 lung carcinoma.
In the review the biological properties (antitumor, antiviral, hypolipidemic, anti-inflammatory, etc.) and bioavailability of betulin and betulinic acid derivatives were discussed. These compounds are isolated from various natural sources, including birch bark (Betula, Betulaceae). The structure-activity correlation was considered for well-known betulinic acid derivatives. The perspectivity of this compounds as active pharmaceutical ingredients was demonstrated by in vitro, in vivo, and ex vivo ...
Betulin (90–94%) was extracted from birch with a non-polar solvent and recrystallized from 2-propanol. Liquid-phase oxidation of betulin aimed at obtaining its biologically active oxo-derivatives (betulone, betulonic and betulinic aldehydes), exhibiting e.g. antitumor, anti-inflammatory, antiparasitic, anticancer and anti-HIV properties, was demonstrated for the first time over gold-based catalysts. Gold was deposited on pristine TiO2 and the same support modified with ceria and lanthana, follow...
Betulin-3,28-dibenzoate and -3,28-diphthalate were synthesized for the first time by reacting betulin with melts of benzoic and phthalic acids at 190–200°C for 5 min.
#1Jana Wiemann(MLU: Martin Luther University of Halle-Wittenberg)H-Index: 8
#2Lucie Heller(MLU: Martin Luther University of Halle-Wittenberg)H-Index: 14
Last. René Csuk(MLU: Martin Luther University of Halle-Wittenberg)H-Index: 27
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Abstract The betulinic acid-derived hydroxamates 5 – 18 , the amides 19 – 24 , and betulin-derived bis-carbamates 25 – 28 as well as the carbamates 31 – 40 and 44 – 48 were prepared and evaluated for their antiproliferative activity in a photometric sulforhodamine B (SRB) assay against several human cancer cell lines and nonmalignant mouse fibroblasts (NIH 3T3). While for 3- O -acetyl hydroxamic acid 5 EC 50 values as low as EC 50 = 1.3 μM were found, N , O -bis-alkyl substituted hydroxamates sh...
Last. Song Yang(Guida: Guizhou University)H-Index: 82
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Abstract Nineteen betulin derivatives modified at the C-3 and C-28 positions were synthesized and assessed for antitumor activities against the MGC-803, PC3, Bcap-37, A375, and MCF-7 human cancer cell lines in vitro by MTT assay. Some derivatives (compounds 3a–3d and 5 ) displayed strong antitumor properties, with IC 50 values between 4 and 18 μM. Compound 3c , containing piperidine group at C-28 position, had IC 50 values of 4.3, 4.5, 5.2, 7.5, and 5.2 μM on the five cancer cell lines, respecti...
As a part of our investigation into new anti-HIV agents, we report herein the isolation, structure elucidation, and biological activity of six new (1–6) and 20 known (7–26) pentacyclic lupane-type triterpenoids from the stem of Cassine xylocarpa and root bark of Maytenus cuzcoina. Their stereostructures were elucidated on the basis of spectroscopic and spectrometric methods, including 1D and 2D NMR techniques. To gain a more complete understanding of the structural requirements for anti-HIV acti...
#2Ewa Michalik(Wrocław Medical University)H-Index: 5
Last. Elwira Chrobak(Medical University of Silesia)H-Index: 10
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The asymmetric unit of the title compound, C30H48O2, contains two independent molecules, the main difference between them being that the isopropenyl group is rotated by approximately 180°. In each molecule, the fused six-membered rings have chair–chair–chair–chair conformations and the cyclopentane ring adopts an envelope conformation with the C atom bearing the hydroxymethyl group as the flap. All ring junctions are trans-fused. With the exception of one of the methyl groups adjacent to th...
Toward developing antileishmanial agents with mode of action targeted to DNA topoisomerases of Leishmania donovani , we have synthesized a large number of derivatives of betulin. The compound, a natural triterpene isolated from the cork layer of Betula spp. plants exhibits several pharmacological properties. Three compounds (disuccinyl betulin, diglutaryl dihydrobetulin, and disuccinyl dihydrobetulin) inhibit growth of the parasite as well as relaxation activity of the enzyme type IB topoisomera...
This paper describes inhibition of Semliki Forest virus (SFV) replication by synthetic derivatives of naturally occurring triterpenoid betulin (1). Chemical modifications were made to OH groups at C-3 and C-28 and to the C-20−C-29 double bond. A set of heterocyclic betulin derivatives was also assayed. A free or acetylated OH group at C-3 was identified as an important structural contributor for anti-SFV activity, 3,28-di-O-acetylbetulin (4) being the most potent derivative (IC50 value 9.1 μM). ...
#1Alexander Barthel(MLU: Martin Luther University of Halle-Wittenberg)H-Index: 13
#2Sebastian Stark(MLU: Martin Luther University of Halle-Wittenberg)H-Index: 7
Last. René Csuk(MLU: Martin Luther University of Halle-Wittenberg)H-Index: 27
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Starting from commercially available betulinol by a combination of several selective oxidation procedures betutinal, betulinic acid, betulonal as well as betulonic acid were obtained in high yields on a multi-gram scale.
