Regio and stereo directional oxidation of ecdysteroids and their 7,8-dihydroanalogs with ozone in pyridine

Савченко, Р. Г.; Urazaeva, Ya. R.; Shafikov, R. V.; Odinokov, V. N.

doi:10.1134/s1070428009080065

Cited by 7 publications

(7 citation statements)

References 13 publications

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“…By repeated hydrolysis of acetonide V we obtained only compound VI which was identical to a sample described in [6]. The 1 H and 13 C NMR spectra of compound IV were identical to those given in [7]. However, the 26-CH 3 and 27-CH 3 signals in the 1 H NMR spectrum reported in [7] were incorrectly given as two singlets, whereas these protons give rise to a single six-proton doublet .…”

mentioning

confidence: 64%

“…The 1 H and 13 C NMR spectra of compound IV were identical to those given in [7]. However, the 26-CH 3 and 27-CH 3 signals in the 1 H NMR spectrum reported in [7] were incorrectly given as two singlets, whereas these protons give rise to a single six-proton doublet . The carbon chemical shifts of the steroid skeleton in the 13 C NMR spectrum of IV were similar to those reported in [6] for 7,8α-dihydro-20-hydroxyecdysone diacetonide VII.…”

mentioning

confidence: 66%

“…The mixture was then treated as described above. Yield 0.23 g (84%), R f 0.52 (CHCl 3 -MeOH, 10 : 1); the melt- ing point, specific optical rotation, and 1 H and 13 C NMR spectra of the product were identical to those given in [7].…”

Section: 8α-dihydroponasterone a (Iii)mentioning

confidence: 97%

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Transformation of ω-anhydro-20-hydroxyecdysone diacetonide into 7,8α-dihydroponasterone a and its acetonides

et al. 2011

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7,8α-Dihydroponasterone A and its mono-and diacetonides were synthesized via catalytic hydrogenation of ω-anhydro-20-hydroxyecdysone 2,3 : 20,22-diacetonide over Pd/C in methanol in the presence of sodium methoxide.Difficultly accessible ecdysteroids and their analogs can be synthesized via transformation of ω-anhydro-20-hydroxyecdysone diacetonide which is a mixture of 24(25)-and 25(26)-dehydroponasterones A (I) formed by dehydration of 20-hydroxyecdisone diacetonide [1,2]. For instance, inokosterone was obtained by reduction of I with sodium tetrahydridoborate [3], whereas ozonolysis of I followed by trifluoromethylation of ω-carbonyl compounds gave 27,27,27-trifluoro-20-hydroxyecdysone [4].We recently reported on a new procedure for the reduction of the C 7 =C 8 double bond in ecdysteroids by catalytic hydrogenation over Pd/C in alkaline methanol solution [5]. Following this procedure, ponasterone A

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confidence: 66%

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Transformation of ω-anhydro-20-hydroxyecdysone diacetonide into 7,8α-dihydroponasterone a and its acetonides

et al. 2011

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“…Compounds 9 are converted to ketoaldehyde ester 4 (in MeOH) or to ketoaldehyde acid 10 (in CH 2 Cl 2 , after hydrolysis). Oxidation of the aldehyde group in compounds 4 and 10 by the complex of pyridine with ozone, which is a good oxidizing agent, [ 34 ] leads to the products 2 and 6 . Formation of ketoacid 6 as a result of hydrolysis of anhydride 7 , which is formed as a result of the elimination of AcOH in molecule 11 , is not excluded.…”

Section: Resultsmentioning

confidence: 99%

Ozonolytic transformations of (R)‐(−)‐carvon in the presence of pyridine

Myasoedova

Garifullina

Belyaeva

et al. 2022

J Chinese Chemical Soc

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Ozonolytic transformations of (R)‐(−)‐carvone in aprotic (CH2Cl2) and proton‐donor (MeOH) solvents in the presence of pyridine were carried out. A low conversion of the starting diene was noted when carrying out controlled ozonolysis by treatment with equivalent of О3. A mixture of 3‐acetyl‐5‐methoxy‐5‐oxopentanoic acid and methyl 4‐oxo‐3‐(2‐oxoethyl)pentanoate in MeOH and 5‐acetyl‐2‐methylcyclohex‐2‐en‐1‐one in CH2Cl2 were formed. Exhaustive ozonolysis of (R)‐(−)‐carvone in CH2Cl2 in the presence of pyridine leads to 3‐acetylpentadioic acid. The monomethyl ether of 3‐acetylpentadioic acid and the product of its cyclization—2,8‐dioxo‐1‐methylbicyclo[3.3.0]octane‐3,7‐dione were formed in MeOH/Py by the treatment of ozone excess.

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“…Yield 0.38 g (94%), R f 0.56 (CHCl 3 -MeOH, 40 : 1), mp 250-252°C, [α] D 20 = +14.95° (c = 1.86, CHCl 3 ) (cf. [10]). The IR and 1 H and 13 C NMR spectra of the product were identical to those reported in [10].…”

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Effective and selective transformations of ecdysteroids into 7,8-dihydro analogs via catalytic hydrogenation under alkaline conditions

et al. 2010

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SHORT COMMUNICATIONSHydrogenation of the double C=C bond in the B ring of ecdysteroids leads to their 7,8-dihydro analogs which are structurally related to brassinosteroids [1]. Attempts to obtain 7,8-dihydro analogs from 20-hydroxyecdysone and its derivatives by reaction with alkali metals in liquid ammonia [2], which is widely used for selective reduction of double bonds in conjugated ketones of the steroid series were unsuccessful [3,4]. Better results were obtained with the use of lithium tetrahydridoaluminate, but the reduction of the C 7 =C 8 double bond was accompanied by reduction of the 6-oxo group [5].Catalytic hydrogenation of ecydisteroids over 10% Pd/C in ethanol was not selective, and the reaction mixtures contained a number of products, including unreacted initial compounds, instead of the desired 7,8-dihydro derivatives [6]. Suksamrarn et al. [7] recently reported on stereoselective catalytic hydrogenation of ∆ 7 -6-oxo steroids in the presence of sodium nitrite [7]; however, 7,8-dihydro analogs of 20-hydroxyecdysone and its derivatives could not be obtained according to this procedure [5].We found that addition of excess metallic sodium to a solution of 20-hydroxyecdysone (I) in methanol and subsequent hydrogenation over 10% Pd/C at room temperature under atmospheric pressure (reaction time ~3 h) gives 20-hydroxy-7,8-dihydroecdysone (II) as the only product which was isolated in ~90% yield by column chromatography on silica gel. Likewise, 2,3:20,22-di-O-isopropylidene-20-hydroxyecdysone (III) and 2,3 : 20,22-di-O-isopropylideneponasterone A (IV) were converted under the same conditions into the corresponding dihydro analogs V and VI (Scheme 1).It is necessary to follow the above operation sequence to obtain 7,8-dihydro analogs of ecdysteroids. When ecdysteroid was added to a preliminarily prepared solution of sodium methoxide in methanol and the catalyst was then added, no hydrogenation of the C 7 =C 8 bond occurred. It was also necessary to bubble hydrogen through the reaction mixture contain-I, II, R 1 = R 2 = R 3 = R 4 = H; III-VI, R 1 R 2 = R 3 R 4 = Me 2 C; I, II, III, V, R 5 = OH; IV, VI, R 5 = H.

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Regio and stereo directional oxidation of ecdysteroids and their 7,8-dihydroanalogs with ozone in pyridine

Cited by 7 publications

References 13 publications

Transformation of ω-anhydro-20-hydroxyecdysone diacetonide into 7,8α-dihydroponasterone a and its acetonides

Transformation of ω-anhydro-20-hydroxyecdysone diacetonide into 7,8α-dihydroponasterone a and its acetonides

Ozonolytic transformations of (R)‐(−)‐carvon in the presence of pyridine

Effective and selective transformations of ecdysteroids into 7,8-dihydro analogs via catalytic hydrogenation under alkaline conditions

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