5073-65-4Relevant academic research and scientific papers
Improved large mesoporous ordered molecular sieves - Stabilization and acid/base functionalization
Kosslick, Hendrik,Pitsch, Irene,Deutsch, Jens,Pohl, Marga-Martina,Schulz, Axel,Tuan, Vu Anh,Tuyen, Nguyen Dinh,Frunza, Ligia,Jaeger, Christian
, p. 54 - 60 (2010)
The preparation of nanoporous materials with enhanced stability using an improved synthesis route using reactive inorganic silica and alumina species is reported. This way improved mesoporous molecular sieves were obtained. The synthesized aluminum substituted mesoporous molecular materials (Al-MMS) contain very large pores of 50-200? size combined with an improved pore wall thickness. Increased wall thickness and Al substitution lead to an improved chemical stability against alkaline solution. The textural, structural and acid properties are investigated by physico-chemical methods. The catalytic performance acidic materials was tested in the benzoylation reaction; amino functionalized materials were studied in the base catalyzed Michael addition.
Identification of Inhibitors of Cholesterol Transport Proteins Through the Synthesis of a Diverse, Sterol-Inspired Compound Collection
Laraia, Luca,Olsen, Asger Hegelund,Whitmarsh-Everiss, Thomas
supporting information, p. 26755 - 26761 (2021/11/17)
Cholesterol transport proteins regulate a vast array of cellular processes including lipid metabolism, vesicular and non-vesicular trafficking, organelle contact sites, and autophagy. Despite their undoubted importance, the identification of selective modulators of this class of proteins has been challenging due to the structural similarities in the cholesterol-binding site. Herein we report a general strategy for the identification of selective inhibitors of cholesterol transport proteins via the synthesis of a diverse sterol-inspired compound collection. Fusion of a primary sterol fragment to an array of secondary privileged scaffolds led to the identification of potent and selective inhibitors of the cholesterol transport protein Aster-C, which displayed a surprising preference for the unnatural-sterol AB-ring stereochemistry and new inhibitors of Aster-A. We propose that this strategy can and should be applied to any therapeutically relevant sterol-binding protein.
Potent Anti-Inflammatory, Arylpyrazole-Based Glucocorticoid Receptor Agonists That Do Not Impair Insulin Secretion
Burke, Susan J.,Campagna, Shawn R.,Collier, J. Jason,Dunlap, Lee E.,Fisch, Alexander R.,Kennedy, Brandon J.,Kirkland, Justin K.,Lato, Ashley M.,Prevatte, Carson W.,Smith, Russell T.,Vogiatzis, Konstantinos D.
, p. 1568 - 1577 (2021/10/04)
Glucocorticoids (GCs) are widely used in medicine for their role in the treatment of autoimmune-mediated conditions, certain cancers, and organ transplantation. The transcriptional activities GCs elicit include transrepression, postulated to be responsible for the anti-inflammatory activity, and transactivation, proposed to underlie the undesirable side effects associated with long-term use. A GC analogue that could elicit only transrepression and beneficial transactivation properties would be of great medicinal value and is highly sought after. In this study, a series of 1-(4-substituted phenyl)pyrazole-based GC analogues were synthesized, biologically screened, and evaluated for SARs leading to the desired activity. Activity observed in compounds bearing an electron deficient arylpyrazole moiety showed promise toward a dissociated steroid, displaying transrepression while having limited transactivation activity. In addition, compounds 11aa and 11ab were found to have anti-inflammatory efficacy comparable to that of dexamethasone at 10 nM, with minimal transactivation activity and no reduction of insulin secretion in cultured rat 832/13 beta cells.
Chemoselective Oxidation of Equatorial Alcohols with N-Ligated λ3-Iodanes
Mikhael, Myriam,Adler, Sophia A.,Wengryniuk, Sarah E.
supporting information, p. 5889 - 5893 (2019/08/26)
The site-selective and chemoselective functionalization of alcohols in complex polyols remains a formidable synthetic challenge. Whereas significant advancements have been made in selective derivatization at the oxygen center, chemoselective oxidation to the corresponding carbonyls is less developed. In cyclic systems, whereas the selective oxidation of axial alcohols is well known, a complementary equatorial selective process has not yet been reported. Herein we report the utility of nitrogen-ligated (bis)cationic λ3-iodanes (N-HVIs) for alcohol oxidation and their unprecedented levels of selectivity for the oxidation of equatorial over axial alcohols. The conditions are mild, and the simple pyridine-ligated reagent (Py-HVI) is readily synthesized from commercial PhI(OAc)2 and can be either isolated or generated in situ. Conformational selectivity is demonstrated in both flexible 1,2-substituted cyclohexanols and rigid polyol scaffolds, providing chemists with a novel tool for chemoselective oxidation.
Synthesis of the Tetracyclic Structure of Batrachotoxin Enabled by Bridgehead Radical Coupling and Pd/Ni-Promoted Ullmann Reaction
Sakata, Komei,Wang, Yinghua,Urabe, Daisuke,Inoue, Masayuki
supporting information, p. 130 - 133 (2018/01/17)
The steroidal ABCD-ring system of the potent neurotoxin batrachotoxin was efficiently assembled in a convergent fashion. Bridgehead radical coupling between the simple AB-ring and D-ring fragments (3 and 4) formed the sterically congested linkage at the C9-oxygen-attached tetrasubstituted carbon. The C-ring was then cyclized by the Pd/Ni-promoted Ullmann reaction of the vinyl triflate and vinyl bromide of 19, giving rise to tetracyclic structure 1.
Total Synthesis of ent-Pregnanolone Sulfate and Its Biological Investigation at the NMDA Receptor
Kapras, Vojtech,Vyklicky, Vojtech,Budesinsky, Milos,Cisarova, Ivana,Vyklicky, Ladislav,Chodounska, Hana,Jahn, Ullrich
supporting information, p. 946 - 949 (2018/02/23)
A unique asymmetric total synthesis of the unnatural enantiomer of pregnanolone, as well as a study of its biological activity at the NMDA receptor, is reported. The asymmetry is introduced by a highly atom-economic organocatalytic Robinson annulation. A new method for the construction of the cyclopentane D-ring consisting of CuI-catalyzed conjugate addition and oxygenation followed by thermal cyclization employing the persistent radical effect was developed. ent-Pregnanolone sulfate is surprisingly only 2.6-fold less active than the natural neurosteroid.
Lipase-catalyzed domino Michael-aldol reaction of 2-methyl-1,3-cycloalkanedione and methyl vinyl ketone for the synthesis of bicyclic compounds
Sano, Kaoru,Kohari, Yoshihito,Nakano, Hiroto,Seki, Chigusa,Takeshita, Mitsuhiro,Tokiwa, Micho,Hirose, Yoshihiko,Uwai, Koji
supporting information, p. 46 - 54 (2016/01/09)
Synthesis of bicyclic compounds was achieved via a lipase-catalyzed, stereoselective, domino Michael-aldol reaction of 2-methyl-1,3-cycloalkanedione and methyl vinyl ketone. Appropriate reaction conditions, including the type of enzyme, solvent, and temperature, were determined. In addition, the effects of solvent polarity and addtives were investigated. The reaction proceeded in the presence of lipase AS in a solution of 20% acetone in dimethylsulfoxide (DMSO) at 10 °C for 8 days, followed by the addition of p-toluenesulfonic acid (TsOH) to afford bicyclic compounds in 51-83% yields with moderate stereoselectivity. Although this domino Michael-aldol reaction showed only moderate stereoselectivity, even with the acid-supported enhancement of the reaction, these results represent potential new applications for lipase.
Synthesis of the ABC skeleton of the aglycon of Echinoside A
Yu, Jun,Yu, Biao
, p. 1331 - 1335 (2015/10/28)
Echinoside A is a triterpene saponin isolated from the sea cucumber Actinopyga echinites (JAEGER), which displays potent antitumor activities in vitro and in vivo. Here, we report the synthesis of the ABC-fused ring skeleton of the aglycon of Echinoside A, with the enantiomerically pure (+)-Wieland-Miescher ketone being used as starting material and a Robinson annulation as the key reaction.
Novel supported and unsupported prolinamides as organocatalysts for enantioselective cyclization of triketones
Pedrosa, Rafael,Andrés, José María,Manzano, Rubén,Pérez-López, César
supporting information, p. 3101 - 3104 (2013/06/27)
A novel prolylsulfonamide derived from ethylene diamine and its supported counterpart has been prepared and tested as enantioselective intramolecular aldol reaction of cyclic and acyclic triketones. Good to excellent yields and enantioselectivities have been obtained in water and under solvent free conditions.
Recyclable L-proline organocatalyst for Wieland-Miescher ketone synthesis
Srivastava, Vivek
, p. 1523 - 1527 (2014/04/03)
Wieland-Miescher ketone 4 was synthesised using L-proline catalyst in the ionic liquid medium via non-selective conjugated addition reaction followed by an enantioselective intermolecular Aldol condensation reaction of triketone 3 intermediate. Short reaction time, recycling of the catalyst, good yield and selectivity are major outcomes of this proposed protocol. Indian Academy of Sciences.
