1778-02-5Relevant academic research and scientific papers
Oxygen-functionalization of C13-angular methyl group in pregnane steroid by means of intramolecular carbony-mediated anodic oxidation
Shibuya,Murakami,Shimada,Yoshikawa,Kitagawa
, p. 1143 - 1147 (1992)
An oxygen-functionalization of the C13-angular methyl group in 3β-acetoxy-5α-pregnan-20-one and its tetra-O-acetyl-β-D-glucopyranosyl derivative has been effected by means of an anodic oxidation mediated by the C20-carbonyl residue in the steroid skeleton.
Dictamnol, a new trinor-guaiane type sesquiterpene, from the roots of Dictamnus dasycarpus Turcz.
Takeuchi,Fujita,Goto,Morisaki,Osone,Tobinaga
, p. 923 - 925 (1993)
A new trinor-guaiane type sesquiterpene, named dictamnol (1), and a steroid, pregnenolone (2), were isolated from Dictamnus dasycarpus Turcz. On the basis of physicochemical evidence, the structure of dictamnol have been elucidated as 8α-methyl-2-methylene-1α,7α-bicyclo[3.5.0]dec-5-en-8β-ol.
Ammonium formate/palladium on carbon: A versatile system for catalytic hydrogen transfer reductions of carbon-carbon double bonds
Paryzek, Zdzislaw,Koenig, Hanna,Tabaczka, Bartlomiej
, p. 2023 - 2026 (2003)
Various carbon-carbon double bonds in olefins and α,β -unsaturated ketones were effectively reduced to the corresponding alkanes and saturated ketones, using ammonium formate as a hydrogen transfer agent in the presence of Pd/C as catalyst in refluxing methanol.
Solid-state nuclear magnetic resonance investigation of neurosteroid compounds and magnesium interactions
Wu, Danni,Carillo, Kathleen Joyce D.,Tsai, Shen-Long,Shie, Jiun-Jie,Tzou, Der-Lii M.
, p. 1318 - 1326 (2019)
The neurosteroid trans-dehydroandrosterone (DHEA) and its analogs with slightly different modifications in the side chain attached to C17, that is, (3S)-acetoxypregn-5-en-20-one (1) and (3S,20R)-acetoxypregn-5-en-20-ol (2), have been synthesized to investigate DHEA–cation interactions. In this study, we applied solid-state 1H/13C cross-polarization/magic-angle spinning (CP/MAS) nuclear magnetic resonance (NMR) spectroscopy to a series of DHEA analog/Mg2+ mixtures at different Mg2+ concentrations. The high-resolution 13C NMR spectra of 1/Mg2+ mixtures exhibit two distinct 13C spectral patterns, one attributable to 1 free from Mg2+, and the other attributable to 1 with bound Mg2+. For 2, the 13C NMR spectra exhibit three distinct spectral patterns; besides that of the free form, the other two can be assigned to Mg2+-bound forms. Based on the analysis of the chemical shift deviations (CSDs), we conclude that both 1 and 2 might be subject to a cation–π interaction via the C5–C6 double bond, in contrast to that observed previously for DHEA. As demonstrated, DHEA possesses two Mg2+ binding sites, that is, C17–O and C5–C6 double bond, in which the binding affinity of the former is at least three times stronger than that of the latter. The solid-state 13C NMR investigation allows better understanding of the underlying cation binding effects of neurosteroid molecules in vitro.
A Mild and Efficient Method for the Reduction of Oximes to Imines for Further in situ Reactions
Barton, Derek H. R.,Motherwell, William B.,Simon, Ethan S.,Zard, Samir Z.
, p. 337 - 338 (1984)
Tributylphosphine-diphenyl disulphide is an effective and mild reagent for reducing oximes to imines.
Inhibition of Ecdysone Biosynthesis: Preparation of Acetylenic Intermediates
Mauvais, Antony,Hetru, Charles,Roussel, Jean Pierre,Luu, Bang
, p. 8597 - 8604 (1993)
Key Words: Ecdysone; C-22 Hydroxylase; Ecdysteroid inhibitor; Acetylenic inhibitor; Hydroboration. Several acetylenic derivatives of ecdysone were synthesized from pregnenolone.These compounds carry an acetylenic function at C-22 and were devised with the aim to inhibit the C-22 hydroxylation of ecdysone biosynthesis by a suicide-substrate mechanism.The five compounds synthesized inhibit the synthesis of ecdysone in the prothoracic glands of Locusta migratoria in vitro.
Convenient synthesis of new pregnenolone oximinyl oxalate dimers
Nahar,Sarker,Turner
, p. 315 - 318 (2008)
Three new symmetrical pregnenolone oxyminyl oxalate dimers (8-10) were synthesized from the corresponding pregnenolone oximes (3, 5, and 7) at room temperature. All dimers were characterised by spectroscopic means, notably HRFABMS and comprehensive NMR spectroscopic data analyses.
Stereochemical Effects in Cyclopropane Ring Openings: Biomimetic Ring Openings of All Isomers of 22,23-Methylenecholesterol Acetate
Zimmerman, Mary P.,Li, Hui-ting,Duax, William L.,Weeks, Charles M.,Djerassi, Carl
, p. 5602 - 5612 (1984)
By using the unique stereochemistry of the side chain in cholesterol, the dynamic influence of proximate chiral centers on the acid-promoted isomerizations of cyclopropanes is defined.Unexpectedly, when the cyclopropane is placed in the 22,23 position, either a backbone rearramgement is induced or a priori unanticipated side-chain olefins arise, each dependent on the stereochemistry of the cyclopropane starting material.The synthesis and stereochamical assignments of the four possible 22,23-methylenecholesterol acetates are reported as well as the effect of stereochemistry on the acid-promoted isomerization of these compounds.Isomers 22 and 23 under the conditions of ring opening yield unexpected backbone rearrangement products of the 3β-acetoxy-(17S)-17,23-dimethyl-18-normethylcholest-5,13(14)-diene type (32-35), which can also be obtained from rearrangement of the Δ5,20(22)- and Δ5,17(20)-23-methylcholestadien-3β-ol acetates (42,44,53,54).The stereochemical criteria governing the course of these isomerizations are discussed.
Chemical synthesis of 7α-hydroxypregnenolone, a neuroactive steroid that stimulates locomotor activity
Yoshimoto, Francis K.,Arman, Hadi D.,Griffith, Wendell P.,Yan, Fangzhi,Wherritt, Daniel J.
, p. 50 - 57 (2017)
7α-Hydroxypregnenolone is an endogenous neuroactive steroid that stimulates locomotor activity. A synthesis of 7α-hydroxypregnenolone from pregnenolone, which takes advantage of an orthogonal protecting group strategy, is described. In detail, the C7-position was oxidized with CrO3 and 3,5-dimethylpyrazole to yield a 7-keto steroid intermediate. The resulting 7-ketone was stereoselectively reduced to the 7α-hydroxy group with lithium tri-sec-butylborohydride. In contrast, reduction of the same 7-ketone intermediate with NaBH4 resulted in primarily the 7β-hydroxy epimer. Furthermore, in an alternative route to the target compound, the 7α-hydroxy group was successfully incorporated by direct C–H allylic benzoyloxylation of pregnenolone-3-acetate with CuBr and tert-butyl peroxybenzoate followed by saponification. The disclosed syntheses to 7-oxygenated steroids are amenable to potentially obtain other biologically active sterols and steroids.
Synthesis of novel pregnane-based 20-carboxamides via palladium-catalysed aminocarbonylation
Mikle, Gábor,Zugó, Alexandra,Szatnik, Erzsébet,Maxim, Anita,Mahó, Sándor,Kollár, László
, p. 1861 - 1867 (2021)
20-Carboxamidopregnene derivatives, such as 3β-acetoxy-5α-pregn-20-ene-20-carboxamides and 5α-pregn-20-ene-20-carboxamides were synthesized from the widely accessible 3β-acetoxy-pregn-5,16-dien-20-one (PDA) using selective hydrogenation, hydrazine and iodoalkene formation, as well as palladium-catalysed aminocarbonylation. The 20-iodo-20-ene derivatives, obtained from the corresponding 20-keto derivatives via their hydrazones, served as substrates. 23 new 20-carboxamides were obtained using various N-nucleophiles ranging from simple primary amines to α-amino acid esters. The novelty of this methodology lies in the application of facile, moderate or high-yielding reactions to obtain otherwise hardly accessible steroidal 20-carboxamides of pharmaceutical importance. In other words, instead of the enzymatic or synthetic degradation of e.g., sterols or cholanic acids, functionalization of the basic skeleton (a ‘building-up’ approach) was used.
