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701.
Maksim E. Mironov Sergey A. Borisov Tatyana V. Rybalova Dmitry S. Baev Tatyana G. Tolstikova Elvira E. Shults 《Molecules (Basel, Switzerland)》2022,27(1)
Steroid sapogenin diosgenin is of significant interest due to its biological activity and synthetic application. A consecutive one-pot reaction of diosgenin, oxalyl chloride, arylacetylenes, and phenylhydrazine give rise to steroidal 1,3,5-trisubstituted pyrazoles (isolated yield 46–60%) when the Stephens–Castro reaction and heterocyclization steps were carried out by heating in benzene. When the cyclization step of alkyndione with phenylhydrazine was performed in 2-methoxyethanol at room temperature, steroidal α,β-alkynyl (E)- and (Z)-hydrazones were isolated along with 1,3,5-trisubstituted pyrazole and the isomeric 2,3,5-trisubstituted pyrazole. The consecutive reaction of diosgenin, oxalyl chloride, phenylacetylene and benzoic acid hydrazides efficiently forms steroidal 1-benzoyl-5-hydroxy-3-phenylpyrazolines. The structure of new compounds was unambiguously corroborated by comprehensive NMR spectroscopy, mass-spectrometry, and X-ray structure analyses. Performing the heterocyclization step of ynedione with hydrazine monohydrate in 2-methoxyethanol allowed the synthesis of 5-phenyl substituted steroidal pyrazole, which was found to exhibit high anti-inflammatory activity, comparable to that of diclofenac sodium, a commercial pain reliever. It was shown by molecular docking that the new derivatives are incorporated into the binding site of the protein Keap1 Kelch-domain by their alkynylhydrazone or pyrazole substituent with the formation of more non-covalent bonds and have higher affinity than the initial spirostene core. 相似文献
702.
The behavior of a planar polyelectrolyte brush subjected to normal and tangential external forces is considered. A new “polyelectrolyte effect” is predicted: shear of a free polyelectrolyte brush leads to a decrease in brush thickness contrary to the case of a free neutral brush. Such behavior is equivalent to that of a neutral brush subjected to an external normal stretching force. In the case of a polyelectrolyte brush this force is created by the osmotic pressure of mobile counterions neutralizing grafted chain charges. Addition of salt diminishes the polyelectrolyte effect and changes the sign of correlation between brush thickness and tangential deformation. 相似文献
703.
Irene L. Odinets Natalya M. Vinogradova Konstantin A. Lyssenko Pavel V. Petrovskii Tatyana A. Mastryukova 《Heteroatom Chemistry》2000,11(2):163-170
Intramolecular cyclization of bis(3‐chloropropyl)‐diethoxythiophosphorylacetonitrile 7, taking place under distillation in vacuo, yields 6‐cyano‐2‐oxa‐10‐thia‐1‐phosphabicyclo[4.4.0]decane‐1‐oxide 10 as a mixture of cis and trans isomers in a 2.3:1 ratio. The isomers were separated chromatographically. For both isomers, single crystals with nonequivalent enantiomeric ratios were obtained under crystallization. The structures of both isomers of bicyclophostone 10 are confirmed by X‐ray study of single crystals. © 2000 John Wiley & Sons, Inc. Heteroatom Chem 11:163–170, 2000 相似文献
704.
Natalia L. Zaichenko Tatyana M. Valova Olga V. Venidiktova Alexander V. Lyubimov Andrey I. Shienok Liubov S. Koltsova Anton O. Ayt Galina V. Lyubimova Leonid D. Popov Valery A. Barachevsky 《Molecules (Basel, Switzerland)》2021,26(22)
Spectral-luminescence properties of a hybrid compound containing a coumarin-type spiropyran and an azomethinocoumarin fragment in toluene-acetonitrile solution in the presence of Li+, Ca2+, Zn2+ and Mg2+ ions are reported. Two excited state proton transfers can occur in the hybrid compound—the transfer of a proton from the OH group of the 7-hydroxy coumarin tautomer to the N atom of the C=N bond of the azomethine fragment leading to green ESIPT fluorescence with a maximum at 540 nm and from the OH group of the 7-hydroxy coumarin tautomer to the carbonyl group of the pyrone chromophore, which leads to the formation of the 2-hydroxyl-tautomer T of coumarin with blue fluorescence with a maximum at 475 nm. Dependence of these excited state proton transfers on the metal nature and irradiation with an external UV source is discussed. 相似文献
705.
Sergey P. Ivonin Andrew A. Tolmachev Tatyana E. Terikovska Andrew A. Anishchenko Alexandra A. Chaikovskaya Alexander M. Pinchuk 《Heteroatom Chemistry》2003,14(3):258-261
Application of N,N‐dimethylhydrazone protective group for synthesis of C‐phosphorylated aldehydes of the pyrrole series was studied. Removal of the hydrazone protection in monophosphorylated pyrrolylcarbaldehyde hydrazones occurs smoothly, while in biphosphorylated derivatives it results in nitrile formation. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:258–261, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10137 相似文献
706.
Inga M. Aladzheva Dmitrii I. Lobanov Ol'ga V. Bykhovskaya Pavel V. Petrovskii Konstantin A. Lyssenko Tatyana A. Mastryukova 《Heteroatom Chemistry》2003,14(7):596-602
A novel facile one‐pot synthesis of the 1,2‐azaphospholanes by intramolecular alkylation of 3‐halopropyl amides of tricoordinate phosphorus has been suggested. Using this method, a series of the differently N‐substituted 1,2‐azaphospholanium salts were synthesized. 3‐Aminopropylphosphine oxides were obtained by hydrolysis of the salts. A probable mechanism of the 1,2‐azaphospholanium salts formation is discussed. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:596–602, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10209 相似文献
707.
708.
Julia G. Knapp Dr. Xijun Wang Dr. Andrew S. Rosen Xingjie Wang Dr. Xinyi Gong Dr. Matthew Schneider Dr. Tatyana Elkin Dr. Kent O. Kirlikovali Dr. Melissa Fairley Dr. Matthew D. Krzyaniak Prof. Michael R. Wasielewski Prof. Nathan C. Gianneschi Prof. Randall Q. Snurr Prof. Omar K. Farha 《Angewandte Chemie (International ed. in English)》2023,62(29):e202305526
The interactions between uranium and non-innocent organic species are an essential component of fundamental uranium redox chemistry. However, they have seldom been explored in the context of multidimensional, porous materials. Uranium-based metal–organic frameworks (MOFs) offer a new angle to study these interactions, as these self-assembled species stabilize uranium species through immobilization by organic linkers within a crystalline framework, while potentially providing a method for adjusting metal oxidation state through coordination of non-innocent linkers. We report the synthesis of the MOF NU-1700 , assembled from U4+-paddlewheel nodes and catecholate-based linkers. We propose this highly unusual structure, which contains two U4+ ions in a paddlewheel built from four linkers—a first among uranium materials—as a result of extensive characterization via powder X-ray diffraction (PXRD), sorption, transmission electron microscopy (TEM), and thermogravimetric analysis (TGA), in addition to density functional theory (DFT) calculations. 相似文献
709.
Dr. Raju Bej Dr. Chuanxiong Nie Dr. Kai Ludwig Dr. Vahid Ahmadi Dr. Jakob Trimpert Julia M. Adler Dr. Tatyana L. Povolotsky Dr. Katharina Achazi Marten Kagelmacher Ricardo Martin Vidal Dr. Jens Dernedde Dr. Benedikt B. Kaufer Prof. Dr. Rainer Haag 《Angewandte Chemie (International ed. in English)》2023,62(29):e202304010
Mucins are the key component of the defensive mucus barrier. They are extended fibers of very high molecular weight with diverse biological functions depending strongly on their specific structural parameters. Here, we present a mucin-inspired nanostructure, produced via a synthetic methodology to prepare methacrylate-based dendronized polysulfates ( MIP-1 ) on a multi gram-scale with high molecular weight (MW=450 kDa) and thiol end-functionalized mucin-inspired polymer ( MIP ) via RAFT polymerization. Cryo-electron tomography (Cryo-ET) analysis of MIP-1 confirmed a mucin-mimetic wormlike single-chain fiber structure (length=144±59 nm) in aqueous solution. This biocompatible fiber showed promising activity against SARS-CoV-2 and its mutant strain, with a remarkable low half maximal (IC50) inhibitory concentration (IC50=10.0 nM). Additionally, we investigate the impact of fiber length on SARS-CoV-2 inhibition by testing other functional polymers ( MIPs ) of varying fiber lengths. 相似文献
710.