- Microbial transformation of dehydroepiandrosterone (DHEA) by some fungi
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In this work, biotransformations of dehydroepiandrosterone (DHEA) 1 by Ulocladium chartarum MRC 72584, Cladosporium sphaerospermum MRC 70266 and Cladosporium cladosporioides MRC 70282 have been reported. U. chartarum MRC 72584 mainly hydroxylated 1 at C-7α and C-7β, accompanied by a minor hydroxylation at C-4β, a minor epoxidation from the β-face and a minor oxidation at C-7 subsequent to its hydroxylations. 3β,7β-Dihydroxy-5β,6β-epoxyandrostan-17-one 6, 3β,4β,7α-trihydroxyandrost-5-en-17-one 7 and 3β,4β,7β-trihydroxyandrost-5-en-17-one 8 from this incubation were identified as new metabolites. C. sphaerospermum MRC 70266 converted some of 1 into a 3-keto-4-ene steroid and then hydroxylated at C-6α, C-6β and C-7α, accompanied a minor 5α-reduction and a minor oxidation at C-6 following its hydroxylations. C. sphaerospermum MRC 70266 also hydroxylated some of 1 at C-7α and C-7β. C. cladosporioides MRC 70282 converted almost half of 1 into a 3-keto-4-ene steroid and then hydroxylated at C-6α and C-6β. C. cladosporioides MRC 70282 also reduced some of 1 at C-17.
- Yildirim, Kudret,Kuru, Ali,Y?lmazer Keskin, Semra,Ergin, Sinan
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p. 465 - 474
(2020/11/12)
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- Metal-Free Allylic Oxidation of Steroids Using TBAI/TBHP Organocatalytic Protocol
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A mild, efficient and organocatalytic allylic oxidation of steroids using a TBAI/TBHP protocol has been developed. A range of bioactive Δ5-en-7-ones can be easily prepared from the corresponding Δ5-steroids. The methodology features several advantages, including readily available starting materials, environmentally benign oxidant, high functional group compatibility, and metal-free catalysis.
- Lam, Ying-Pong,Yeung, Ying-Yeung
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supporting information
p. 2369 - 2372
(2018/04/19)
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- Biohydroxylation of 7-oxo-DHEA, a natural metabolite of DHEA, resulting in formation of new metabolites of potential pharmaceutical interest
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Metabolism of steroids in healthy and unhealthy human organs is the subject of extensive clinical and biomedical studies. For this kind of investigations, it is essential that the reference samples of new derivatives of natural, physiologically active steroids (especially those difficult to achieve in the chemical synthesis) become available. This study demonstrated for the first time transformation of 7-oxo-DHEA—a natural metabolite of DHEA, using Syncephalastrum racemosum cells. The single-pulse fermentation of substrate produced two new hydroxy metabolites: 1β,3β-dihydroxy-androst-5-en-7,17-dione and 3β,12β-dihydroxy-androst-5-en-7,17-dione, along with the earlier reported 3β,9α-dihydroxy-androst-5-en-7,17-dione and 3β,17β-dihydroxy-androst-5-en-7-one. Simultaneously, the same metabolites, together with small quantities of 7α- and 7β-hydroxy-DHEA, as well as the products of their reduction at the C-17 were obtained after transformation of DHEA under pulse-feeding of the substrate. The observed reactions suggested that this micro-organism contains enzymes exhibiting similar activity to those present in human cells. Thus, the resulting compounds can be considered as potential components of the eukaryotic, including human, metabolome.
- ?wizdor, Alina,Panek, Anna,Milecka-Tronina, Natalia
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p. 844 - 849
(2016/11/11)
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- Scalable and sustainable electrochemical allylic C-H oxidation
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New methods and strategies for the direct functionalization of C-H bonds are beginning to reshape the field of retrosynthetic analysis, affecting the synthesis of natural products, medicines and materials. The oxidation of allylic systems has played a prominent role in this context as possibly the most widely applied C-H functionalization, owing to the utility of enones and allylic alcohols as versatile intermediates, and their prevalence in natural and unnatural materials. Allylic oxidations have featured in hundreds of syntheses, including some natural product syntheses regarded as € classics €. Despite many attempts to improve the efficiency and practicality of this transformation, the majority of conditions still use highly toxic reagents (based around toxic elements such as chromium or selenium) or expensive catalysts (such as palladium or rhodium). These requirements are problematic in industrial settings; currently, no scalable and sustainable solution to allylic oxidation exists. This oxidation strategy is therefore rarely used for large-scale synthetic applications, limiting the adoption of this retrosynthetic strategy by industrial scientists. Here we describe an electrochemical C-H oxidation strategy that exhibits broad substrate scope, operational simplicity and high chemoselectivity. It uses inexpensive and readily available materials, and represents a scalable allylic C-H oxidation (demonstrated on 100 grams), enabling the adoption of this C-H oxidation strategy in large-scale industrial settings without substantial environmental impact.
- Horn, Evan J.,Rosen, Brandon R.,Chen, Yong,Tang, Jiaze,Chen, Ke,Eastgate, Martin D.,Baran, Phil S.
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- N-Hydroxyphthalimide catalyzed allylic oxidation of steroids with t-butyl hydroperoxide
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A new and optimized procedure for the allylic oxidation of Δ5-steroids with t-butyl hydroperoxide in the presence of catalytic amounts of N-hydroxyphthalimide (NHPI) under mild conditions was developed, showing excellent regioselectivity and chemoselectivity (functional group compatibility). It was found that Co(OAc)2 could enhance the catalytic ability of NHPI resulting in better yields and shorter reaction times. The reaction mechanism and the scope of the reaction with a variety of Δ5-steroidal substrates were also investigated.
- Zhao, Qian,Qian, Chao,Chen, Xin-Zhi
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- Allylic oxidation of steroidal olefins by vanadyl acetylacetonate and tert-butyl hydroperoxide
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Abstract Readily available vanadyl acetylacetonate was found to oxidize the allylic sites of Δ5 steroidal alcohols without protection of hydroxyl groups. Cholesterol, dehydroepiandrosterone, cholesterol benzoate, cholesterol acetate, pregnenolone, and 5-pregnen-3,20-diene were oxidized to 7-keto products using vanadyl acetylacetonate in one pot reactions at room temperature in the presence of oxygen and water.
- Grainger, Wendell S.,Parish, Edward J.
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p. 103 - 109
(2015/06/30)
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- Hydroxylation of DHEA and its analogues by Absidia coerulea AM93. Can an inducible microbial hydroxylase catalyze 7α- and 7β-hydroxylation of 5-ene and 5α-dihydro C19-steroids?
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In this paper we focus on the course of 7-hydroxylation of DHEA, androstenediol, epiandrosterone, and 5α-androstan-3,17-dione by Absidia coerulea AM93. Apart from that, we present a tentative analysis of the hydroxylation of steroids in A. coerulea AM93. DHEA and androstenediol were transformed to the mixture of allyl 7-hydroxy derivatives, while EpiA and 5α-androstan-3,17-dione were converted mainly to 7α- and 7β-alcohols accompanied by 9α- and 11α-hydroxy derivatives. On the basis of (i) time course analysis of hydroxylation of the abovementioned substrates, (ii) biotransformation with resting cells at different pH, (iii) enzyme inhibition analysis together with (iv) geometrical relationship between the C-H bond of the substrate undergoing hydroxylation and the cofactor-bound activated oxygen atom, it is postulated that the same enzyme can catalyze the oxidation of C7-Hα as well as C7-H β bonds in 5-ene and 5α-dihydro C19-steroids. Correlations observed between the structure of the substrate and the regioselectivity of hydroxylation suggest that 7β-hydroxylation may occur in the normal binding enzyme-substrate complex, while 7α-hydroxylation - in the reverse inverted binding complex.
- Milecka-Tronina, Natalia,Ko?ek, Teresa,?wizdor, Alina,Panek, Anna
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p. 883 - 891
(2014/01/23)
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- Hydroxylation of DHEA, androstenediol and epiandrosterone by Mortierella isabellina AM212. Evidence indicating that both constitutive and inducible hydroxylases catalyze 7α- as well as 7β-hydroxylations of 5-ene substrates
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The course of transformation of DHEA, androstenediol and epiandrosterone in Mortierella isabellina AM212 culture was investigated. The mentioned substrates underwent effective hydroxylation; 5-ene substrates - DHEA and androstenediol - were transformed into a mixture of 7α- and 7β- allyl alcohols, while epiandrosterone was converted into 7α- (mainly), 11α- and 9α- monohydroxy derivatives. Ketoconazole and cycloheximide inhibition studies suggest the presence of constitutive and substrate-induced hydroxylases in M. isabellina. On the basis of time course analysis of the hydroxylation of DHEA and androstenediol, the oxidation of allyl C7-Hα and C7-Hβ bonds by the same enzyme is a reasonable assumption.
- Kolek, Teresa,Milecka, Natalia,Swizdor, Alina,Panek, Anna,Bialonska, Agata
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p. 5414 - 5422
(2011/09/13)
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- CrO3/NHPI adsorbed on activated clay: A new supported reagent for allylic selective oxidation of Δ5-sterols
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Chromium trioxide and N-hydroxyphthalimide (NHPI) supported on activated clay could serve as an efficient and mild oxidant for allylic selective oxidation of Δ5-sterols. Thus, a ketone group could be easily introduced into the allylic position of Δ5-sterols with the existence of a sensitive 3β-hydroxyl group. The oxidant residue can be removed easily from the reaction mixture by filtration and reused after reactivation at 120δC for 4-6 h. Copyright Taylor & Francis Group, LLC.
- Liu, Jin,Zhu, Hong-You,Cheng, Xiao-Hong
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experimental part
p. 1076 - 1083
(2009/09/06)
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- Optimal TBHP allylic oxidation of Δ5 - Steroids catalyzed by dirhodium caprolactamate
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Dirhodium caprolactamate is the most efficient catalyst for the oxidation of Δ5-steroids to 7-keto-Δ5-steroids by 70% tert-butyl hydroperoxide in water (T-HYDRO). Isolated product yields range from 38 to 87%.
- Choi, Hojae,Doyle, Michael P.
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p. 5349 - 5352
(2008/09/17)
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- Novel methods for the preparation of dhea derivatives
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The invention relates to a method for the production of DHEA derivatives, such as 7-oxo-DHEA and 7-hydroxy-DHEA, from DHEA itself.
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Page/Page column 10
(2010/11/25)
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- Allylic and benzylic oxidation reactions with sodium chlorite
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Various allylic and benzylic substrates were selectively oxidized to the corresponding enones in good yields using sodium chlorite, either in combination with tert-butyl hydroperoxide in stoichiometric conditions, or associated with N-hydroxyphthalimide as catalyst. These oxidation reactions were effectively and economically performed under mild, transition-metal free conditions and therefore the dual challenge of cost effectiveness and benign nature of the processes was met with.
- Silvestre, Samuel M.,Salvador, Jorge A.R.
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p. 2439 - 2445
(2007/10/03)
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- Bismuth-catalyzed allylic oxidation using t-butyl hydroperoxide
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Bismuth(III) salts are efficient catalysts for the selective allylic oxidation using tert-butyl hydroperoxide. BiCl3 is especially effective and can be easily recovered and reused as BiOCl. Using BiCl 3/K-10 as catalyst, an increase in the reaction rate was observed.
- Salvador, Jorge A.R.,Silvestre, Samuel M.
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p. 2581 - 2584
(2007/10/03)
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- MICROBIAL PROCESS FOR THE PREPARATION OF 7-KETO DEHYDROEPIANDROSTERONE AND RELATED ANALOGS
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The present invention relates to a two part microbial process for the preparation of 7-oxo-5-androstene steroids of Formula III.
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- Anti-proliferative action of endogenous dehydroepiandrosterone metabolites on human cancer cell lines.
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Dehydroepiandrosterone (DHEA) is a naturally occurring steroid synthesized in the adrenal cortex, gonads, brain, and gastrointestinal tract, and it is known to have chemopreventive and anti-proliferative actions on tumors. These effects are considered to be induced by the inhibition of glucose-6-phosphate dehydrogenase (G6PD) and/or HMG-CoA reductase (HMGR) activities. The present study was undertaken to investigate whether endogenous DHEA metabolites, i.e. DHEA-sulfate, 7-oxygenated DHEA derivatives, androsterone, epiandrosterone, and etiocholanolone, have anti-proliferative effects on cancer cells and to clarify which enzyme, G6PD or HMGR, is responsible for growth inhibition. Growth of Hep G2, Caco-2, and HT-29 cells, evaluated by 3-[4,5-dimethylthiazol]-2yl-2,5-diphenyl tetrazolium bromide (MTT) and bromodeoxyuridine incorporation assays, was time- and dose-dependently inhibited by addition of all DHEA-related steroids we tested. In particular, the growth inhibition due to etiocholanolone was considerably greater than that caused by DHEA in all cell lines. The suppression of growth of the incubated steroids was not correlated with the inhibition of G6PD (r=-0.031, n=9, NS) or HMGR (r=0.219, n=9, NS) activities. The addition of deoxyribonucleosides or mevalonolactone to the medium did not overcome the inhibition of growth induced by DHEA or etiocholanolone, while growth suppression by DHEA was partially prevented by the addition of ribonucleosides. These results demonstrate that endogenous DHEA metabolites also have an anti-proliferative action that is not induced by inhibiting G6PD or HMGR activity alone. These non-androgenic DHEA metabolites may serve as chemopreventive or anti-proliferative therapies.
- Yoshida, Shigemasa,Honda, Akira,Matsuzaki, Yasushi,Fukushima, Sugano,Tanaka, Naomi,Takagiwa, Aya,Fujimoto, Yoshinori,Miyazaki, Hiroshi,Salen, Gerald
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- Process for effecting allylic oxidation using dicarboxylic acid imides and chromium reagents
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A procedure for oxidizing organic compounds having allylic hydrogen atom(s) involving the steps of reactively contacting the organic compound with a combination of an N-hydroxy dicarboxylic acid imide and a chromium-containing oxidant. The reaction can conveniently be conducted under ambient temperature and pressure conditions, and is conveniently conducted in a co-solvent system of water and organic solvent(s).
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Page column 9-10
(2008/06/13)
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- Ergosteroids VII: perchloric acid-induced transformations of 7-oxygenated steroids and their bio-analytical applications--a liquid chromatographic-mass spectrometric study.
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Sulfate esters of 7-oxo-delta(5)-steroids can be selectively and quantitatively hydrolyzed to the corresponding free steroids in the presence of carboxylic acid esters by solvolysis with perchloric acid in ethyl acetate at room temperature. Sulfates as well as carboxylic acid esters, methyl ethers, and ketals can be quantitatively converted to the corresponding 3,5-diene-7-one derivatives by heating with perchloric acid in methanol at 65 degrees C. The dienes have a strong UV absorption with maximum centered around 284 nm. These reactions have been used for the characterization and structural elucidation of 7-oxygenated-delta(5)-steroids that are present in complex biomatrices and can also be used for the quantitative estimation of total 7-oxo-delta(5)-steroids (free as well as conjugated) in biological matrices.
- Marwah, Ashok,Marwah, Padma,Lardy, Henry
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p. 233 - 248
(2007/10/03)
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- Steroid transformations with Fusarium oxysporum var. cubense and Colletotrichum musae
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The utility of two locally isolated fungi, pathogenic to banana, for steroid biotransformation has been studied. The deuteromycetes Fusarium oxysporum var. cubense (IMI 326069, UAMH 9013) and Colletotrichum musae (IMI 374528, UAMH 8929) had not been examined previously for this potential. In general, F. oxysporum var. cubense effected 7α hydroxylation on 3β-hydroxy- Δ5-steroids, 6β, 12β, and 15α hydroxylation on steroidal-4-ene-3-ones, side-chain degradation on 17α,21-dihydroxypregnene-3,20-diones, and 15α hydroxylation on estrone. Both strains were shown to perform redox reactions on alcohols and ketones.
- Wilson, Maureen R.,Gallimore, Winklet A.,Reese, Paul B.
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p. 834 - 843
(2007/10/03)
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- Ergosteroids II: Biologically active metabolites and synthetic derivatives of dehydroepiandrosterone
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An improved procedure for the synthesis of 3β-hydroxyandrost-5-ene- 7,17-dione, a natural metabolite of dehydroepiandrosterone (DHEA) is described. The synthesis and magnetic resonance spectra of several other related steroids are presented. Feeding dehydroepiandrosterone to rats induces enhanced formation of several liver enzymes among which are mitochondrial sn-glycerol 3-phosphate dehydrogenase (GPDH) and cytosolic malic enzyme. The induction of these two enzymes, that complete a thermogenic system in rat liver, was used as an assay to search for derivatives of DHEA that might be more active than the parent steroid. Activity is retained in steroids that are reduced to the corresponding 17β-hydroxy derivative, or hydroxylated at 7α or 7β, and is considerably enhanced when the 17-hydroxy or 17-carbonyl steroid is converted to the 7-oxo derivative. Several derivatives of DHEA did not induce the thermogenic enzymes whereas the corresponding 7-oxo compounds did. Both short and long chain acyl esters of DHEA and of 7-oxo-DHEA are active inducers of the liver enzymes when fed to rats. 7-Oxo-DHEA-3-sulfate is as active as 7-oxo-DHEA or its 3-acetyl ester, whereas DHEA-3-sulfate is much less active than DHEA. Among many steroids tested, those possessing a carbonyl group at position 3, a methyl group at 7, a hydroxyl group at positions 1, 2, 4, 11, or 19, or a saturated B ring, with or without a 4-5 double bond, were inactive.
- Lardy, Henry,Kneer, Nancy,Wei, Yong,Partridge, Bruce,Marwah, Padma
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p. 158 - 165
(2007/10/03)
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- Microbiological Transformations. Part 3. The Oxidation of Androstene Derivatives with the Fungus Cunninghamella elegans
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The products obtained from the incubation of some Δ4- and Δ5-androstene derivatives with Cunninghamella elegans are largely those arising from allylic oxidation or epoxidation of the double bond, but some 9-, 12-, 14-, and 16-hydroxylation also occurs.
- Crabb, Trevor A.,Dawson, Philip J.,Williams, Roger O.
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p. 2535 - 2541
(2007/10/02)
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