- Synthesis of steroid bisglucuronide and sulfate glucuronide reference materials: Unearthing neglected treasures of steroid metabolism
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Doubly or bisconjugated steroid metabolites have long been known as minor components of the steroid profile that have traditionally been studied by laborious and indirect fractionation, hydrolysis and gas chromatography-mass spectrometry (GC–MS) analysis. Recently, the synthesis and characterisation of steroid bis(sulfate) (aka disulfate or bis-sulfate) reference materials enabled the liquid chromatography-tandem mass spectrometry (LC–MS/MS) study of this metabolite class and the development of a constant ion loss (CIL) scan method for the direct and untargeted detection of steroid bis(sulfate) metabolites. Methods for the direct LC–MS/MS detection of other bisconjugated steroids, such as steroid bisglucuronide and mixed steroid sulfate glucuronide metabolites, have great potential to reveal a more complete picture of the steroid profile. However, access to steroid bisglucuronide or sulfate glucuronide reference materials necessary for LC–MS/MS method development, metabolite identification or quantification is severely limited. In this work, ten steroid bisglucuronide and ten steroid sulfate glucuronide reference materials were synthesised through an ordered combination of chemical sulfation and/or enzymatic glucuronylation reactions. All compounds were purified and characterised using NMR and MS methods. Chemistry for the preparation of stable isotope labelled steroid {13C6}-glucuronide internal standards has also been developed and applied to the preparation of two selectively mono-labelled steroid bisglucuronide reference materials used to characterise more completely MS fragmentation pathways. The electrospray ionisation and fragmentation of the bisconjugated steroid reference materials has been studied. Preliminary targeted ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis of the reference materials prepared revealed the presence of three steroid sulfate glucuronides as endogenous human urinary metabolites.
- Pranata, Andy,Fitzgerald, Christopher C.,Khymenets, Olha,Westley, Erin,Anderson, Natasha J.,Ma, Paul,Pozo, Oscar J.,McLeod, Malcolm D.
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supporting information
p. 25 - 40
(2019/01/04)
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- New structure-activity relationships of A-and D-ring modified steroidal aromatase inhibitors: Design, synthesis, and biochemical evaluation
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A- and D-ring androstenedione derivatives were synthesized and tested for their abilities to inhibit aromatase. In one series, C-3 hydroxyl derivatives were studied leading to a very active compound, when the C-3 hydroxyl group assumes 3β stereochemistry (1, IC50 = 0.18 μM). In a second series, the influence of double bonds or epoxide functions in different positions along the A-ring was studied. Among epoxides, the 3,4-epoxide 15 showed the best activity (IC50 = 0.145 μM) revealing the possibility of the 3,4-oxiran oxygen resembling the C-3 carbonyl group of androstenedione. Among olefins, the 4,5-olefin 12 (IC50 = 0.135 μM) revealed the best activity, pointing out the importance of planarity in the A,B-ring junction near C-5. C-4 acetoxy and acetylsalicyloxy derivatives were also studied showing that bulky substituents in C-4 diminish the activity. In addition, IFD simulations helped to explain the recognition of the C-3 hydroxyl derivatives (1 and 2) as well as 15 within the enzyme.
- Varela, Carla,Tavares Da Silva, Elisiário J.,Amaral, Cristina,Correia Da Silva, Georgina,Baptista, Teresa,Alcaro, Stefano,Costa, Giosuè,Carvalho, Rui A.,Teixeira, Natércia A. A.,Roleira, Fernanda M. F.
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experimental part
p. 3992 - 4002
(2012/07/30)
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- Steroidal isomers with uniform mass spectra of their per-TMS derivatives: Synthesis of 17-hydroxyandrostan-3-ones, androst-1-, and -4-ene-3,17-diols
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In human sports doping control analysis most of the steroids are analyzed after enzymatic hydrolysis of the glucuronides as per-trimethylsilyl (TMS) derivatives applying gas chromatography-mass spectrometry (GC-MS). According to the recommendations of the World Anti-Doping Agency the identification of analytes should be based on retention time and on mass spectrometric characterization. This study shows that the bis-TMS derivatives of 16 specific C19 steroids, namely the stereoisomers of 5ξ-androst-1-ene-3ξ,17ξ-diol (8 isomers), androst-4-ene-3ξ,17ξ-diol (4 isomers), and 17ξ-hydroxy-5ξ-androstan-3-one (4 isomers), reveal very similar mass spectra. As a rule, when taking the retention times, which are provided as Kovac indices for all these isomers, into account, a restriction to two or three possible isomers is possible. Reliable identification should additionally include a comparison of the retention times of the analytes with the reference compounds measured concomitantly. In some cases standard addition may be appropriate. Due to the limited availability, the above mentioned isomers were synthesized by reduction of the corresponding α,β-unsaturated oxo steroids either with K-Selectride or by catalytic hydrogenation (Pd/C as catalyst). The products of the reactions were identified by means of nuclear magnetic resonance (NMR) characterization and by further reduction to the corresponding 5ξ-androstane-3ξ,17ξ-diols and GC-MS comparison with commercially available reference standards.
- Parr, Maria K.,Zapp, Josef,Becker, Michael,Opfermann, Georg,Bartz, Ulrike,Schaenzer, Wilhelm
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p. 545 - 551
(2008/02/02)
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- Reduction of steroidal ketones with amine - Boranes
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Complexes of secondary amines with borane, R2NH·BH 3, surpass sodium borohydride as reducing agents for saturated and unsaturated steroidal 3-, 12-, 17-, and 20-ketones as regards chemo- and regioselectivity and mildness of the reaction conditions. In the case of 12-ketones, stereoselectivity is also improved.
- Leontjev,Vasiljeva,Pivnitsky
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p. 703 - 708
(2007/10/03)
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- The Reduction of Steroid 2α-Fluoro 4-En-3-ones
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Reduction of testosterone with potassium tri-(R,S)-sec-butylborohydride gives predominantly the allylic 3β-alcohol, while 2α-fluorotestosterone is converted solely to 2α-fluoro-4-androstene-3α,17β-diol, and 2α-fluoro-4-androstene-3,17-dione to 2α-fluoro-3α-hydroxy-4-androsten-17-one.Reduction of testosterone with (R,R)- or (S,S)-Rh-DIOP and dihydrosilanes give predominantly allylic alcohols, while with the same catalysts and monohydrosilanes no allylic alcohols are found, the 4-double bond being instead reduced.The chirality of the DIOP reagents contributes only to a minor extent to stereoselectivity of 3-ketone reduction.
- Goeendos, Gyoergy,McGirr, Larry G.,Jablonski, Chester R.,Snedden, Walter,Orr, James C.
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p. 3057 - 3059
(2007/10/02)
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- A GENERAL METHOD FOR THE SELECTIVE REDUCTION OF KETONES IN THE PRESENCE OF ENONES.
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Ketones can be reduced in the presence of conjugated enones by sodium borohydride in 50percent methanol in dichloromethane at -78 deg C.The selectivity is generally excellent.In favorable cases the reaction can be carried out at room temperature in dichloromethane with acetic acid as catalyst.
- Ward, Dale E.,Rhee, Chung K.,Zoghaib, Wajdi M.
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p. 517 - 520
(2007/10/02)
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- SELECTIVITE DE LA REDUCTION D'α-ENONES POLYCYCLIQUES PAR LES BOROHYDRURES: EFFET DE L'ADDITION DE TETRAMETHYL-ETHYLENEDIAMINE AU BOROHYDRURE DE TETRABUTYLAMMONIUM
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Δ1,9octalone, Δ1,9-10-methyl octalone and testosterone were reduced by NBu4BH4, alone or in the presence of tetramethylethylenediamine (TMEDA), in THF and in toluene.With TMEDA, the first step of the reduction is the regioselective 1,4 attack by BH4(1-) which leads either to the saturated ketones or to the corresponding saturated alcohols.The results observed under different conditions were interpreted by the intervention of various reductive species: diborane, enoxyborohydrides in the absence of TMEDA, amine-borane in its presence.
- D'incan, E.,Loupy, A.,Maia, A.,Seyden-Penne, J.,Viout, P.
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p. 2923 - 2927
(2007/10/02)
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- Identification by gas chromatography mass spectrometry of intermediates in the aromatization of modified C19 steroids by human placental microsomes
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Analogs of 4 androstene 3,17 dione and testosterone were tested as substrates for the aromatizing enzyme complex of human placenta. Compounds modified in rings B, C, and D were found to be aromatized via a pathway similar to that postulated for 4 androstene 3,17 dione and testosterone, in which oxidation to the 19 hydroxy and 19 oxo (or corresponding gem diol) intermediates occurs. No evidence of additional intermediates was obtained.
- Braselton Jr,Orr,Engel
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p. 411 - 433
(2007/10/13)
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