scholarly journals Synthesis of chiral sulfoximine-based thioureas and their application in asymmetric organocatalysis

2012 ◽  
Vol 8 ◽  
pp. 1443-1451 ◽  
Author(s):  
Marcus Frings ◽  
Isabelle Thomé ◽  
Carsten Bolm
Keyword(s):  
Biginelli Reaction ◽  
Core Fragment ◽  
Asymmetric Organocatalysis ◽  
Synthetic Routes ◽  
Catalytic Asymmetric ◽  
First Time ◽  
Sulfur Containing

For the first time, chiral sulfoximine derivatives have been applied as asymmetric organocatalysts. In combination with a thiourea-type backbone the sulfonimidoyl moiety leads to organocatalysts showing good reactivity in the catalytic desymmetrization of a cyclic meso-anhydride and moderate enantioselectivity in the catalytic asymmetric Biginelli reaction. Straightforward synthetic routes provide the newly designed thiourea-sulfoximine catalysts in high overall yields without affecting the stereohomogeneity of the sulfur-containing core fragment.

COTTONWEED MARSH (MARSH). CHEMICAL COMPOSITION OF ETHANOL EXTRACT

2020 ◽  
Vol 5 (4) ◽  
pp. 29-32
Author(s):  
V. Platonov ◽  
V. Dunaev ◽  
G. Suhih ◽  
M. Shatskiy ◽  
M. Volochaeva
Keyword(s):  
Chemical Composition ◽  
Mass Spectra ◽  
Ethanol Extract ◽  
Structural Group ◽  
Quantitative Content ◽  
Wide Range ◽  
Structural Formulas ◽  
First Time ◽  
Sulfur Containing

For the first time, a detailed study of the chemical composition of ethanol extract of dried marsh (swamp), a product obtained after preliminary exhaustive last ex-traction with n-hexane, toluene, chloroform and acetone was performed. Chromatography-mass spectrometry made it possible to identify 119 individual compounds in this extract with the determination of their quantitative content, mass spectra and structural formulas, and the calculation of the structural-group composition was performed. A characteristic feature of the extract is the presence of significant amounts of nitrogen and sulfur-containing compounds (20.04), esters (21.47), sterols (18.54), carboxylic acids (8.15) and hydrocarbons (7.15) (wt. % of the extract). In addition, the extract contains phenols, ketones, aldehydes, alcohols and glycosides: 5.01; 4.34; 4.88; 3.16 and 3.12 (wt. % of the extract), respectively. Dominance in the extract of nitrogen-sulfur-containing and compounds; environment of sterols-betulin and its derivatives, esters, as well as the presence of different structure of phenols, glycosides, aldehydes and alcohols makes it possible to assume a wide range of pharmacological activity of drugs based on ethanol extract of dried marsh (marsh).

scholarly journals INFLUENCE OF ACTIVE ACIDITY OF THE MEDIUM ON THE STABILITY OF MNO NANOPARTICLES

2020 ◽  
pp. 33-41
Author(s):  
Андрей Владимирович Блинов ◽  
Давид Гурамиевич Маглакелидзе ◽  
Александр Александрович Кравцов ◽  
Анастасия Александровна Блинова ◽  
Алексей Алексеевич Гвозденко ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Amino Acids ◽  
Scanning Electron Microscopy ◽  
Manganese Dioxide ◽  
Mass Ratios ◽  
Manganese Dioxide Nanoparticles ◽  
The Stability ◽  
First Time ◽  
Sulfur Containing ◽  
Scanning Electron

В работе впервые представлены результаты исследования микроструктуры наночастиц диоксида марганца, стабилизированных серосодержащими аминокислотами. По результатам сканирующей электронной микроскопии обнаружено наличие в образцах наночастиц диаметром 15 - 30 нм. С помощью спектрофотомерии установлены оптимальные массовые соотношения прекурсоров для получения стабильных золей наночастиц диоксида марганца, которые составляют KMnO: метионин - 1:1 и KMnO: цистеин - 3:1. Исследование влияния активной кислотности среды на стабильность наночастиц диоксида марганца показало, что образцы MnO, полученные с использованием метионина, стабильны при 4 ≤ pH ≤ 11, а с использованием цистеина стабильны при 5 ≤ pH ≤ 8. In this work, for the first time the results of studying the microstructure of manganese dioxide nanoparticles stabilized with sulfur-containing amino acids are presented. According to the results of scanning electron microscopy, nanoparticles with a diameter of 15 - 30 nm were presented in the samples. The optimal mass ratios of precursors were established by means of spectrophotometry, to obtain stable sols of manganese dioxide nanoparticles. The optimal mass ratios were: KMnO : methionine - 1:1 and KMnO : cysteine - 3:1. Investigation of the effect of the medium active acidity on the stability of manganese dioxide nanoparticles showed that MnO samples obtained with methionine are stable at 4 ≤ pH ≤ 11, and with cysteine - at 5 ≤ pH ≤ 8 .

Catalytic asymmetric [2+2] cycloaddition between quinones and fulvenes and a subsequent stereoselective isomerization to 2,3-dihydrobenzofurans

2017 ◽  
Vol 53 (49) ◽  
pp. 6585-6588 ◽  
Author(s):  
Haifeng Zheng ◽  
Chaoran Xu ◽  
Yan Wang ◽  
Tengfei Kang ◽  
Xiaohua Liu ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Chiral Lewis Acid ◽  
Acid Catalyzed ◽  
Catalytic Asymmetric ◽  
First Time ◽  
Cyclobutane Derivatives

A chiral Lewis acid catalyzed enantioselective [2+2] cycloaddition between quinones and fulvenes was reported for the first time. The method afforded a series of [6,4,5]-tricyclic cyclobutane derivatives in good yields with excellent regio- and stereoselectivities. Furthermore, the [2+2] adducts could be easily converted into formal [3+2] adducts efficiently and stereoselectively.

scholarly journals Synthesis of structurally diverse 3,4-dihydropyrimidin-2(1H)-ones via sequential Biginelli and Passerini reactions

2017 ◽  
Vol 13 ◽  
pp. 54-62 ◽  
Author(s):  
Andreas C Boukis ◽  
Baptiste Monney ◽  
Michael A R Meier
Keyword(s):  
Multicomponent Reactions ◽  
Biginelli Reaction ◽  
2D Nmr ◽  
Solvent System ◽  
Solvent Mixture ◽  
Tandem Reaction ◽  
Reaction Step ◽  
Passerini Reaction ◽  
One Pot ◽  
First Time

The Biginelli reaction was combined with the Passerini reaction for the first time in a sequential multicomponent tandem reaction approach. After evaluation of all possible linker components and a suitable solvent system, highly functionalized dihydropyrimidone–α-acyloxycarboxamide compounds were obtained in good to excellent yields. In a first reaction step, different 3,4-dihydropyrimidin-2(1H)-one acids were synthesized, isolated and fully characterized. These products were subsequently used in a Passerini reaction utilizing a dichloromethane/dimethyl sulfoxide solvent mixture. By variation of the components in both multicomponent reactions, a large number of structurally diverse compounds could be synthesized. In addition, a one-pot Biginelli–Passerini tandem reaction was demonstrated. All products were carefully characterized via 1D and 2D NMR as well as IR and HRMS.

scholarly journals Iridium Catalyzed Synthesis of Tetrahydro-1H-Indoles by Dehydrogenative Condensation

Inorganics ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 97 ◽  
Author(s):  
Forberg ◽  
Kallmeier ◽  
Kempe
Keyword(s):  
Title Compound ◽  
Secondary Alcohols ◽  
Pd Catalyst ◽  
Pincer Ligand ◽  
Reaction Conditions ◽  
Iridium Catalyst ◽  
Synthetic Procedure ◽  
Reaction Proceeds ◽  
Synthetic Routes ◽  
First Time

Novel synthetic routes to the commonly encountered indole motif are highly sought after. Tetrahydro-1H-indoles were synthesized for the first time from secondary alcohols and 2aminocyclohexanol in the presence of a well-established iridium catalyst using a modified synthetic procedure recently developed for the synthesis of hydrocarbazoles. The catalyst is stabilized by an inexpensive and easy-to-synthesize triazine based PN5P pincer ligand. The reaction proceeds through acceptorless dehydrogenative condensation (ADC) and yields the title compound, dihydrogen, and water and can thus be classified as sustainable synthesis. Overall, five examples, three of which were previously unknown compounds, were prepared. The propitious isolated yields and the mild reaction conditions show the synthetic value of this approach. These tetrahydroindoles can be quantitatively dehydrogenated over a heterogeneous Pd catalyst to yield the corresponding indoles.

Two Synthetic Routes to The Formation of Tungsten Oxide Hybrid Compounds

2004 ◽  
Vol 847 ◽  
Author(s):  
S.V. Chong ◽  
B. Ingham ◽  
J.L. Tallon
Keyword(s):  
Tungsten Oxide ◽  
Sol Gel ◽  
Dip Coating ◽  
Ammonia Solution ◽  
Nitrogen Atmosphere ◽  
Tungstic Acid ◽  
Hybrid Films ◽  
Hybrid Compounds ◽  
Synthetic Routes ◽  
First Time

ABSTRACTThe syntheses of tungsten oxide-organic amine hybrids via homogenous and heterogeneous routes were explored and compared. In the former case, tungstic acid (H2WO4) and an appropriate amine were dissolved in ammonia solution under nitrogen atmosphere, and the product was precipitated out via evaporation of the solvent. In heterogeneous synthesis, a non-aqueous approach was employed in which H2WO4 powder was aged in a solution consisting of the amine dissolved in an appropriate organic solvent. XRD and FTIR showed that the hybrid materials obtained from the two different methods are identical. Based on these findings, we were able to prepare tungsten oxide hybrid films for the first time, by dip-coating tungstic acid films prepared from sol-gel techniques, in a non-aqueous diamine solution. The XRD spectra of these films exhibit a series of harmonic peaks, indexed as [00k ], which correspond to the Bragg peaks for the hybrid compounds. SEM shows the morphology of tungstic acid changes from the irregularly shaped platelets to a needle-like structure of the hybrids and resulted in a loosely packed coating.

Catalytic asymmetric Meerwein–Ponndorf–Verley reduction of glyoxylates induced by a chiral N,N′-dioxide/Y(OTf)3complex

2017 ◽  
Vol 53 (22) ◽  
pp. 3232-3235 ◽  
Author(s):  
Wangbin Wu ◽  
Sijia Zou ◽  
Lili Lin ◽  
Jie Ji ◽  
Yuheng Zhang ◽  
...  
Keyword(s):  
Catalytic Asymmetric ◽  
First Time ◽  
Mpv Reduction ◽  
Mechanism Of The Reaction

An asymmetric MPV reduction of glyoxylates was for the first time achieved with excellent results and the mechanism of the reaction was probed.

scholarly journals Metalloradical activation of α-formyldiazoacetates for the catalytic asymmetric radical cyclopropanation of alkenes

2017 ◽  
Vol 8 (6) ◽  
pp. 4347-4351 ◽  
Author(s):  
Xue Xu ◽  
Yong Wang ◽  
Xin Cui ◽  
Lukasz Wojtas ◽  
X. Peter Zhang
Keyword(s):  
Catalytic Asymmetric ◽  
First Time

For the first time, α-formyldiazoacetates (FDA), have been successfully applied for asymmetric olefin cyclopropanationviaCo(ii)-based metalloradical catalysis.

Green Approach for the Reduction of Graphene Oxide by Thai Shallot

2016 ◽  
Vol 675-676 ◽  
pp. 696-699 ◽  
Author(s):  
Voranuch Thongpool ◽  
Akapong Phunpheok ◽  
Veeradate Piriyawong ◽  
Supanee Limsuwan
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Visible Spectroscopy ◽  
Green Approach ◽  
Reduced Graphene ◽  
Uv Visible ◽  
First Time ◽  
Sulfur Containing ◽  
Sulfur Containing Compounds ◽  
Scanning Electron

In this paper, we used shallots in the reduction of graphene oxide for the first time. Flavone, sulfur-containing compounds, and polyphenolic derivatives in the bulb of shallot acted as good reducing agent for the reduction of GO. The GO and reduced graphene oxide (RGO) were characterized by scanning electron microscopy (SEM), ultraviolet (UV)-visible spectroscopy, thermogravimetric analysis (TGA) and Raman spectroscopy. GO and RGO were the transparent sheets with the sheet edges tend to scroll and fold slightly. RGO showed a maximum absorption peak at 267 nm and had better thermal stability than graphene oxide. Raman spectra indicated removal of oxygen at the surface of GO and formation of the defect in the graphene sheet.

Catalytic asymmetric oxidative carbonylation-induced kinetic resolution of sterically hindered benzylamines to chiral isoindolinones

2021 ◽  
Vol 57 (14) ◽  
pp. 1778-1781
Author(s):  
Qiu-Qi Mu ◽  
Yi-Xue Nie ◽  
Hang Li ◽  
Xing-Feng Bai ◽  
Xue-Wei Liu ◽  
...  
Keyword(s):  
Transition Metal ◽  
Kinetic Resolution ◽  
Oxidative Carbonylation ◽  
Sterically Hindered ◽  
Transition Metal Catalyzed ◽  
Catalytic Asymmetric ◽  
Metal Catalyzed ◽  
First Time

A highly enantioselective kinetic resolution of sterically hindered benzylamines has been achieved for the first time through transition-metal-catalyzed oxidative carbonylation.

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