Synthesis of 19β,28-epoxy-23,24-dinor-A-neo-18α-olean-4-en-3-one from betulin

Medvedeva, N. I.; Флехтер, О. Б.; Куковинец, О. С.; Галин, Ф. З.; Толстиков, Г. А.; Baglin, Isabelle; Cavé, Christian

doi:10.1007/s11172-007-0125-x

Cited by 18 publications

(10 citation statements)

References 7 publications

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“…On the other hand, creation of hybrid molecules can consist of designing the separate parts (cycles, side chain) of the natural metabolites. An example of this is the hybrid oleanane 4,4dinortriterpenoids with an A-steroidal cycle [7,8].…”

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confidence: 99%

One-pot Synthesis of Hollongdione from Dipterocarpol

Смирнова

Казакова

Huong

et al. 2014

Natural Product Communications

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A one-pot synthesis of a hybrid triterpenoid-steroid molecule, hollongdione (22,23,24,25,26,27-hexanordammar-3,20-dion), was achieved in a yield of 89%, based on the selective dehydration of dipterocarpol following ozonolysis. The structure of hollongdione was confirmed by X-ray analysis for the first time. Dammar-20(22),24(25)-dien inhibited the growth of Mycobacterium tuberculosis (strain H37Rv) in vitro with a MIC of 50 µg/mL.

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confidence: 99%

One-pot Synthesis of Hollongdione from Dipterocarpol

Смирнова

Казакова

Huong

et al. 2014

Natural Product Communications

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“…Compounds were detected using H 2 SO 4 solution (10%) with subsequent heating at 100-120°C for 2-3 min. Allobetulin (1) was obtained as before [16]. …”

Section: Methodsmentioning

confidence: 99%

Allylic oxidation of 19β,28-epoxy-a-neo-5β-methyl-25-nor-18α-olean-9-ene

et al. 2011

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The oleanane triterpenoid allobetulin (1) is an available betulin derivative [1]. Allobetulin is known to exhibit moderate inhibiting activity against type B flu virus [2] whereas 28-oxoallobetulone is an effective inhibitor of type A flu virus replication [3]. Derivatives of allobetulin have manifested antifeedant activity against larvae of Heliothis zea [4] and Leptinotarsa decemlineata [5]. The antitumor activity of allobetulin derivatives is practically unstudied [6].Herein we report the synthesis of a new allobetulin derivative that is of interest for modifications on rings A and B. Allobetulin (1) was dehydrated to 19E,28-epoxy-A-neo-18D-olean-3(5)-ene (2), which was then isomerized into 19E,28-epoxy-A-neo-5E-methyl-25-nor-18D-olean-9-ene (3) in 75% yield by the action of acetylchloride upon refluxing in CH 3 CN. Reaction with ozone caused allyl oxidation of 3 to form 19E,28-epoxy-A-neo-5E-methyl-25-nor-18D-olean-9-en-1-one (4), the structure of which was confirmed by NMR spectroscopy. Thus, the 13 C NMR spectra exhibited 30 resonances that were assigned using DEPT spectra [7] to quaternary, methine, methylene, and methyl groups. Resonances of 8 quaternary C atoms, 5 methines, 10 methylenes, and 7 methyls were found. Resonances of carbonyl C-1 (G C 208.13 ppm), methine C-19 (87.93), and methylene C-28 (71.21) C atoms, which were oxygenated, had characteristic chemical shifts.COSY and HETCOR spectra were analyzed in order to establish the positions of resonances for protonated C atoms and their protons in 4. According to COSY spectra, the methylene protons in the D-position relative to the carbonyl (H ax -2, G H 2.06 ppm and H eq -2, G H 2.41 ppm) formed an ABX-system with the H-3 proton (G H 1.39). The spin-spin coupling constant was 12.3 Hz, indicating a trans-diaxial coupling and an axial position for H-3. Therefore, the isopropyl group occupied the equatorial position. Correlation peaks in the HETCOR spectrum H ax -2(H eq -2)/C-2 and H-3/C-3 and cross peaks of H-3 with the methine proton of the isopropyl group H-4 (G H 1.69) in the COSY spectrum enabled the structure and substitution stereochemistry of five-membered ring A to be found. The chemical shifts of quaternary C atoms on the C-9 (G C 156.10 ppm) and C-10 (G C 139.76) double bond corresponded with its position in ring B [8].

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“…The syntheses of different allobetulin derivatives have been described comprehensively in the literature [2,3,6,[9][10][11][12][13][14][15][16][17][18][19][20]; however, attention to their pharmaco logical activity has been given only in the last few years [21][22][23][24][25][26][27][28][29][30][31]. It was found that allobetulin derivatives pos sess anti inflammatory, antiulcerous [22], antiviral [26,27], and immunoregulatory activities [30].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and cytotoxicity of allobetulin derivatives

et al. 2014

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The synthesis and screening of antitumor activity in vitro (cytotoxicity) of various oxygen, nitrogen, sulfur and platinum-containing derivatives of allobetulin, including different arrangements of the double bonds in the A and B rings, penta- and hexacyclic ring A, 21-acetyl-20,28-epoxy-18α,19βH-ursane-isomeric cycle E, was carry out. (3R,5R)-19β,28-Epoxy-4,5-seco-18α-olean-3(5)-ozonide and 2,3-indolo-21β-acetyl-20β,28-epoxy-18α, H-19β-ursane showed significant cytotoxic activity against melanoma MeWo and Leukemia SR cells, appropriately. (3S,5S)-Diastereomer of the first compound showed no cytotoxicity.

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Synthesis of 19β,28-epoxy-23,24-dinor-A-neo-18α-olean-4-en-3-one from betulin

Cited by 18 publications

References 7 publications

One-pot Synthesis of Hollongdione from Dipterocarpol

One-pot Synthesis of Hollongdione from Dipterocarpol

Allylic oxidation of 19β,28-epoxy-a-neo-5β-methyl-25-nor-18α-olean-9-ene

Synthesis and cytotoxicity of allobetulin derivatives

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