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4,855 Results Found

  • Article
  • Open Access
4 Citations
2,636 Views
13 Pages

Vinylation of N-Heteroarenes through Addition/Elimination Reactions of Vinyl Selenones

  • Martina Palomba,
  • Italo Franco Coelho Dias,
  • Michelangelo Cocchioni,
  • Francesca Marini,
  • Claudio Santi and
  • Luana Bagnoli

12 August 2023

A new protocol for the synthesis of N-vinyl azoles using vinyl selenones and azoles in the presence of potassium hydroxide was developed. This reaction proceeded under mild and transition metal-free conditions through an addition/elimination cascade...

  • Article
  • Open Access
45 Citations
8,357 Views
10 Pages

31 January 2005

Application of the extended Grunwald-Winstein equation to solvolyses of n-propyl chloroformate in a variety of pure and binary solvents indicates an addition-elimination pathway in the majority of the solvents but an ionization pathway in the solvent...

  • Article
  • Open Access
21 Citations
7,895 Views
11 Pages

Rate and Product Studies of Solvolyses of Benzyl Fluoroformate

  • Jin Burm Kyong,
  • Seung Han Ryu and
  • Dennis N. Kevill

5 July 2006

The specific rates of solvolysis of benzyl fluoroformate have been measured inseveral hydroxylic solvents at 25.0 °C. For methanolysis, the solvent deuterium isotopeeffect and activation parameters were determined and activation parameters were alsod...

  • Article
  • Open Access
1 Citations
5,446 Views
12 Pages

A previous study of the effect of a 2-chloro substituent on the rates and the mechanisms of the solvolysis of ethyl chloroformate is extended to the effect of a 3-chloro substituent on the previously studied solvolysis of propyl chloroformate and to...

  • Article
  • Open Access
1 Citations
2,352 Views
14 Pages

25 November 2022

Optically active dialkoxyisopropylsulfonium salts were obtained by methylation (ethylation) of optically active alkyl isopropanesulfinates using methyl (ethyl) trifluoromethanesulfonate. Alkaline hydrolysis of a series of methoxy(alkoxy)sulfonium sal...

  • Article
  • Open Access
6 Citations
12,951 Views
13 Pages

2 March 2009

The specific rates of solvolysis of ethyl fluoroformate have been measured at 24.2 °C in 21 pure and binary solvents. These give a satisfactory correlation over the full range of solvents when the extended Grunwald-Winstein equation is applied. The s...

  • Article
  • Open Access
2 Citations
3,591 Views
15 Pages

Free Radical Isomerizations in Acetylene Bromoboration Reaction

  • Hugo Semrád,
  • Ctibor Mazal and
  • Markéta Munzarová

25 April 2021

The experimentally motivated question of the acetylene bromoboration mechanism was addressed in order to suggest possible radical isomerization pathways for the syn-adduct. Addition–elimination mechanisms starting with a bromine radical attack at the...

  • Article
  • Open Access
12 Citations
9,801 Views
24 Pages

11 February 2015

The synthesis of optically active sulfinic acid esters has been accomplished by the acid catalyzed alcoholysis of optically active sulfinamides. Sulfinates are formed in this reaction with a full or predominant inversion of configuration at chiral su...

  • Article
  • Open Access
17 Citations
9,256 Views
29 Pages

Perfluoro Allyl Fluorosulfate (FAFS): A Versatile Building Block for New Fluoroallylic Compounds

  • Ivan Wlassics,
  • Vito Tortelli,
  • Serena Carella,
  • Cristiano Monzani and
  • Giuseppe Marchionni

4 August 2011

In this study we will present and discuss both the synthesis of CF2=CFCF2OSO2F (perfluoroallyl fluorosulfate, FAFS), focusing in particular on the important role of C3F6/SO3 ratio, reaction temperature and boron catalyst/SO3 ratio on FAFS’ yield and...

  • Article
  • Open Access
5 Citations
7,090 Views
12 Pages

Correlation of the Rates of Solvolysis of i-Butyl Fluoroformate and a Consideration of Leaving-Group Effects

  • Yelin Lee,
  • Kyoung-Ho Park,
  • Mi Hye Seong,
  • Jin Burm Kyong and
  • Dennis N. Kevill

10 November 2011

The specific rates of solvolysis of isobutyl fluoroformate (1) have been measured at 40.0 °C in 22 pure and binary solvents. These results correlated well with the extended Grunwald-Winstein (G-W) equation, which incorporated the NT solvent nucleophi...

  • Review
  • Open Access
7 Citations
10,417 Views
23 Pages

10 October 2014

The replacement of oxygen within a chloroformate ester (ROCOCl) by sulfur can lead to a chlorothioformate (RSCOCl), a chlorothionoformate (ROCSCl), or a chlorodithioformate (RSCSCl). Phenyl chloroformate (PhOCOCl) reacts over the full range of solven...

  • Article
  • Open Access
5 Citations
2,954 Views
13 Pages

Dipeptides of S-Substituted Dehydrocysteine as Artzyme Building Blocks: Synthesis, Complexing Abilities and Antiproliferative Properties

  • Paweł Lenartowicz,
  • Mateusz Psurski,
  • Aleksandra Kotynia,
  • Aleksandra Pieniężna,
  • Monika Cuprych,
  • Klaudia Poniatowska,
  • Justyna Brasuń and
  • Paweł Kafarski

22 February 2021

Background: Dehydropeptides are analogs of peptides containing at least one conjugate double bond between α,β-carbon atoms. Its presence provides unique structural properties and reaction centre for chemical modification. In this study, the series of...

  • Article
  • Open Access
16 Citations
15,691 Views
12 Pages

Extended Grunwald-Winstein Analysis - LFER Used to Gauge Solvent Effects in p-Nitrophenyl Chloroformate Solvolysis

  • Malcolm J. D’Souza,
  • Kevin E. Shuman,
  • Shannon E. Carter and
  • Dennis N. Kevill

13 November 2008

Specific rates of solvolysis at 25oC for p-nitrophenyl chloroformate (1) are analyzed using the extended (two-term) Grunwald-Winstein equation. For 39 solvents, the sensitivities (l = 1.68±0.06 and m = 0.46±0.04) towards changes in solvent nucleophil...

  • Communication
  • Open Access
1 Citations
1,564 Views
8 Pages

Fragmentation and Branch Elimination of Primary α′ Martensite in Additively Manufactured Ti-6Al-4V Alloy

  • Mansur Ahmed,
  • Fionnan McNamara,
  • Greg Duggan,
  • Charles Tomonto,
  • Garret E. O’Donnell and
  • Rocco Lupoi

6 December 2023

Fragmentation and branch elimination are generally noticed in the conventionally processed Ti-6Al-4V. Such a key morphological change produces a positive change in certain mechanical properties. We, for the first time, observe fragmentation and branc...

  • Article
  • Open Access
13 Citations
9,532 Views
14 Pages

15 February 2011

The specific rates of solvolysis of neopentyl chloroformate (1) have been determined in 21 pure and binary solvents at 45.0 °C. In most solvents the values are essentially identical to those for ethyl and n-propyl chloroformates. However, in aqueous-...

  • Communication
  • Open Access
2 Citations
2,990 Views
8 Pages

DBU Promoted Polysubstituted Arene Formation via a Michael Addition/Cyclization/Elimination Cascade Reaction

  • Guishun Bai,
  • Yang Yang,
  • Xingyue Wang,
  • Jiamin Wu,
  • Hong Wang,
  • Xinyi Ye and
  • Xiaoze Bao

23 November 2022

The straightforward construction of polysubstituted arenes is essential in both synthetic chemistry and medicinal chemistry. Herein, we reported a DBU promoted Michael addition/cyclization/elimination cascade reaction between vinylogous malononitrile...

  • Communication
  • Open Access
15 Citations
5,010 Views
8 Pages

24 January 2020

Here, we describe a mild, catalyst-free and operationally-simple strategy for the direct fluoroalkylation of olefins driven by the photochemical activity of an electron donor−acceptor (EDA) complex between DMA and fluoroalkyl iodides. The signi...

  • Article
  • Open Access
23 Citations
4,848 Views
17 Pages

Increasing Damping of Thin-Walled Structures Using Additively Manufactured Vibration Eliminators

  • Paweł Dunaj,
  • Stefan Berczyński,
  • Karol Miądlicki,
  • Izabela Irska and
  • Beata Niesterowicz

3 May 2020

The paper presents a new way to conduct passive elimination of vibrations consisting of covering elements of structures with low dynamic stiffness with polylactide (PLA). The PLA cover was created in 3D printing technology. The PLA cover was connecte...

  • Article
  • Open Access
1 Citations
2,304 Views
13 Pages

Towards Highly Efficient, Additively Manufactured Passive Vibration Eliminators for Mechanical Systems

  • Izabela Irska,
  • Grzegorz Kramek,
  • Karol Miądlicki,
  • Paweł Dunaj,
  • Stefan Berczyński and
  • Elżbieta Piesowicz

1 February 2023

Structural damping largely determines the dynamic properties of mechanical structures, especially those whose functioning is accompanied by time-varying loads. These loads may cause vibrations of a different nature, which adversely affects the functi...

  • Article
  • Open Access
4 Citations
2,104 Views
26 Pages

Packing Incubation and Addition of Rot Fungi Extracts Improve BTEX Elimination from Air in Biotrickling Filters

  • Piotr Rybarczyk,
  • Krzysztof Cichon,
  • Karolina Kucharska,
  • Dominik Dobrzyniewski,
  • Bartosz Szulczyński and
  • Jacek Gębicki

18 September 2024

The removal of benzene, toluene, ethylbenzene, and xylene (BTEX) from air was investigated in two similar biotrickling filters (BTFs) packed with polyurethane (PU) foam, differing in terms of inoculation procedure (BTF A was packed with pre-incubated...

  • Article
  • Open Access
6 Citations
3,181 Views
28 Pages

An Easy Synthesis of Monofluorinated Derivatives of Pyrroles from β-Fluoro-β-Nitrostyrenes

  • Alexander S. Aldoshin,
  • Andrey A. Tabolin,
  • Sema L. Ioffe and
  • Valentine G. Nenajdenko

The catalyst-free conjugate addition of pyrroles to β-Fluoro-β-nitrostyrenes was investigated. The reaction was found to proceed under solvent-free conditions to form 2-(2-Fluoro-2-nitro-1-arylethyl)-1H-pyrroles. The effectiveness of this approach wa...

  • Article
  • Open Access
14 Citations
3,632 Views
21 Pages

Non-Antagonistic Contradictoriness of the Progress of Advanced Digitized Production with SARS-CoV-2 Virus Transmission in the Area of Dental Engineering

  • Leszek A. Dobrzański,
  • Lech B. Dobrzański,
  • Anna D. Dobrzańska-Danikiewicz,
  • Joanna Dobrzańska,
  • Karolina Rudziarczyk and
  • Anna Achtelik-Franczak

4 September 2020

The general goals of advanced digitized production in the Industry 4.0 stage of the industrial revolution were presented along with the extended holistic model of Industry 4.0, introduced by the authors, indicating the importance of material design a...

  • Article
  • Open Access
13 Citations
3,317 Views
16 Pages

Elimination of Clogging of a Biogas Slurry Drip Irrigation System Using the Optimal Acid and Chlorine Addition Mode

  • Xuefeng Qiu,
  • Jiandong Wang,
  • Haitao Wang,
  • Chuanjuan Wang,
  • Yuechao Sun and
  • Guangyong Li

As an emerging contaminant, the clogging substances of emitters in biogas slurry drip irrigation systems affect the efficient return and utilization of biogas slurry to the field to a great extent. This can be prevented using acid and chlorination as...

  • Communication
  • Open Access
2 Citations
9,092 Views
6 Pages

Synthesis and Crystal Structure of 9-(4,6-dichloro-1,3,5-triazin-2-yl)-9H-carbazole

  • Aamer Saeed,
  • Madiha Kazmi,
  • Shahid Ameen Samra and
  • Ulrich Flörke

26 April 2011

A carbazole-triazine hybrid was prepared by addition-elimination between carbazole and 2,4,6-trichlorotriazine in the presence of base. The compound shows intensely blue fluorescence both in solution and solid state when irradiated with UV-radiation....

  • Article
  • Open Access
4 Citations
3,847 Views
21 Pages

2-(2-(Dimethylamino)vinyl)-4H-pyran-4-ones as Novel and Convenient Building-Blocks for the Synthesis of Conjugated 4-Pyrone Derivatives

  • Dmitrii L. Obydennov,
  • Diana I. Nigamatova,
  • Alexander S. Shirinkin,
  • Oleg E. Melnikov,
  • Vladislav V. Fedin,
  • Sergey A. Usachev,
  • Alena E. Simbirtseva,
  • Mikhail Y. Kornev and
  • Vyacheslav Y. Sosnovskikh

16 December 2022

A straightforward approach for the construction of the new class of conjugated pyrans based on enamination of 2-methyl-4-pyrones with DMF-DMA was developed. 2-(2-(Dimethylamino)vinyl)-4-pyrones are highly reactive substrates that undergo 1,6-conjugat...

  • Article
  • Open Access
3 Citations
2,059 Views
12 Pages

23 July 2024

Using Ni(II) as the catalyst, electron-deficient 3,5-dimethylacryloylpyrazole olefin was reacted with C,N-diarylnitrones alone for 10 min to prepare novel five-member heterocyclic products, 4-3,5-dimethylacryloylpyrazole isoxazolidines with 100% regi...

  • Article
  • Open Access
6 Citations
2,479 Views
11 Pages

Metal-Free Eliminative C-H Arylthiolation of 2H-Imidazole N-Oxides with Thiophenols

  • Egor A. Nikiforov,
  • Nailya F. Vaskina,
  • Timofey D. Moseev,
  • Mikhail V. Varaksin,
  • Valery N. Charushin and
  • Oleg N. Chupakhin

24 June 2023

A synthetic strategy based on reactions of cyclic imine oxides, namely 2H-imidazole 1-oxides, with thiophenols mediated by acetyl chloride was successfully applied as a convenient tool to obtain a series of novel azaheterocyclic molecules, including...

  • Article
  • Open Access
1 Citations
1,245 Views
17 Pages

18 March 2025

Iodosulfonylation of an ethynyl group at the C2 position of 2′-deoxyadenosine or adenosine with TsI provides (E)-2-(β-iodovinyl)sulfones. The latter undergo nucleophilic substitution with amines via an addition–elimination to give &b...

  • Article
  • Open Access
34 Citations
9,035 Views
17 Pages

30 April 2007

Additional specific rates of solvolysis are determined for phenyl chloroformate.These values are combined with literature values to give a total of 49 data points, which areused within simple and extended Grunwald-Winstein treatments. Literature valu...

  • Article
  • Open Access
12 Citations
12,443 Views
15 Pages

29 June 2010

Correlation of the solvent effects through application of the extended Grunwald-Winstein equation to the solvolysis of isopropyl chlorothioformate results in a sensitivity value of 0.38 towards changes in solvent nucleophilicity (l) and a sensitivity...

  • Article
  • Open Access
11 Citations
9,716 Views
18 Pages

10 January 2012

The specific rates of solvolysis of 2-butyn-1-yl-chloroformate (1) and 2-methoxyphenyl chloroformate (2) are studied at 25.0 °C in a series of binary aqueous-organic mixtures. The rates of reaction obtained are then analyzed using the extended Grunwa...

  • Article
  • Open Access
1,976 Views
11 Pages

20 October 2024

This study investigated the acyl group transfer reactions of 2,4-dinitrophenyl 5-substituted-2-furoates, promoted by 4-substituted phenoxides/phenols in a 20 mol% DMSO aqueous solution at 25 °C. The reactions yielded nucleophilic substitution pro...

  • Article
  • Open Access
9 Citations
9,674 Views
14 Pages

17 July 2019

Activation of carbonyl moiety is one of the most rudimentary approaches in organic synthesis and is crucial for a plethora of industrial-scale condensation reactions. In esterification and aldol condensation, which represent two of the most important...

  • Feature Paper
  • Article
  • Open Access
13 Citations
5,138 Views
8 Pages

Reactivation of VX-Inhibited Human Acetylcholinesterase by Deprotonated Pralidoxime. A Complementary Quantum Mechanical Study

  • Jorge Alberto Valle da Silva,
  • Ander Francisco Pereira,
  • Steven R. LaPlante,
  • Kamil Kuca,
  • Teodorico Castro Ramalho and
  • Tanos Celmar Costa França

27 January 2020

In the present work, we performed a complementary quantum mechanical (QM) study to describe the mechanism by which deprotonated pralidoxime (2-PAM) could reactivate human (Homo sapiens sapiens) acetylcholinesterase (HssAChE) inhibited by the nerve ag...

  • Article
  • Open Access
7 Citations
3,326 Views
19 Pages

30 September 2022

The human microbiome is a vast collection of microbial species that exist throughout the human body and regulate various bodily functions and phenomena. Of the microbial species that exist in the human microbiome, those within the archaea domain have...

  • Review
  • Open Access
2 Citations
4,241 Views
21 Pages

Analogy of the Reactions of Aromatic and Aliphatic π-Electrophiles with Nucleophiles

  • Michał Barbasiewicz,
  • Michał Fedoryński,
  • Rafał Loska and
  • Mieczysław Mąkosza

The aim of this essay is to disclose the similarity of a great variety of reactions that proceed between nucleophiles and π-electrophiles—both aromatic and aliphatic. These reactions proceed via initial reversible addition, followed by a var...

  • Article
  • Open Access
22 Citations
5,341 Views
19 Pages

6 December 2017

CF3CBrCH2 (2-bromo-3,3,3-trifluoropropene, 2-BTP) is a potential replacement for CF3Br; however, it shows conflicted inhibition and enhancement behaviors under different combustion conditions. To better understand the combustion chemistry of 2-BTP, a...

  • Article
  • Open Access
180 Views
26 Pages

14 January 2026

Photovoltaic (PV) power generation is essential for achieving carbon neutrality and advancing renewable energy development. In Northwest China, the rapid expansion of PV installations requires accurate and timely spatial data to support effective mon...

  • Article
  • Open Access
9 Citations
6,235 Views
16 Pages

Novel Polycarbo-Substituted Alkyl (Thieno[3,2-c]quinoline)-2-Carboxylates: Synthesis and Cytotoxicity Studies

  • Malose Jack Mphahlele,
  • Marole Maria Maluleka,
  • Tshepiso Jan Makhafola and
  • Peace Mabeta

13 November 2014

Direct one-pot base-promoted conjugate addition–elimination of 6,8-dibromo-4-chloroquinoline-3-carbaldehyde with methyl mercaptoacetate and subsequent cyclization afforded methyl [(6,8-dibromothieno[3,2-c]quinoline)]-2-carboxylate. The latter undergo...

  • Review
  • Open Access
13 Citations
6,642 Views
8 Pages

15 March 2022

Sodium–glucose cotransporter (SGLT) inhibitors are a class of oral hypoglycemic agents, which, in recent years, have been shown to improve renal and cardiovascular outcomes in patients with diabetic and non-diabetic chronic kidney disease. Ther...

  • Article
  • Open Access
2 Citations
1,484 Views
14 Pages

26 October 2024

The topography of surfaces produced by metal additive manufacturing is a challenge for optical measurement systems such as focus variation microscopes. These irregularities can lead to artifacts, such as incorrectly measured protrusions or spikes, ha...

  • Article
  • Open Access
7 Citations
7,382 Views
14 Pages

Aqueous Chlorination of D-Limonene

  • Albert T. Lebedev,
  • Elena A. Detenchuk,
  • Tomas B. Latkin,
  • Mojca Bavcon Kralj and
  • Polonca Trebše

Limonene (1-methyl-4-(1-methylethenyl)-cyclohexene) is one of the most widespread monocyclic terpenes, being both a natural and industrial compound. It is widely present in the environment, including in water supplies. Therefore, it may be subjected...

  • Review
  • Open Access
12 Citations
11,491 Views
52 Pages

Asymmetric Electrophilic Reactions in Phosphorus Chemistry

  • Anastasy O. Kolodiazhna and
  • Oleg I. Kolodiazhnyi

6 January 2020

This review is devoted to the theoretic and synthetic aspects of asymmetric electrophilic substitution reactions at the stereogenic phosphorus center. The stereochemistry and mechanisms of electrophilic reactions are discussed—the substitution,...

  • Article
  • Open Access
10 Citations
4,730 Views
20 Pages

11 January 2024

The additive noise in the condition monitoring system using fiber Bragg grating (FBG) sensors, including white Gaussian noise and multifrequency interference, has a significantly negative influence on the fault diagnosis of rotating machinery. Spectr...

  • Article
  • Open Access
3 Citations
2,154 Views
16 Pages

Development of New Drugs to Treat Tuberculosis Based on the Dinitrobenzamide Scaffold

  • Tiago Delgado,
  • João P. Pais,
  • David Pires,
  • Filipe G. A. Estrada,
  • Rita C. Guedes,
  • Elsa Anes and
  • Luis Constantino

27 April 2024

Tuberculosis (TB) continues to be a major global health challenge and a leading cause of death from infectious diseases. Inspired by the results from a previous work by our group on antimycobacterial N-alkylnitrobenzamides, which are structurally rel...

  • Short Note
  • Open Access
5 Citations
8,588 Views
11 Pages

28 May 2015

In glacial acetic acid, phthalanilic acid and its monosubstituents are known to be converted to the corresponding phthalimides in relatively good yields. In this study, we computationally investigated the experimentally proposed two-step (addition-el...

  • Article
  • Open Access
5 Citations
10,233 Views
21 Pages

20 March 2020

The chloride-chloride exchange reaction in arenesulfonyl chlorides was investigated experimentally and theoretically by density functional theory (DFT) calculations. The second order rate constants and activation parameters of this identity reaction...

  • Article
  • Open Access
20 Citations
6,250 Views
22 Pages

New Cysteine Protease Inhibitors: Electrophilic (Het)arenes and Unexpected Prodrug Identification for the Trypanosoma Protease Rhodesain

  • Philipp Klein,
  • Patrick Johe,
  • Annika Wagner,
  • Sascha Jung,
  • Jonas Kühlborn,
  • Fabian Barthels,
  • Stefan Tenzer,
  • Ute Distler,
  • Waldemar Waigel and
  • Tanja Schirmeister
  • + 3 authors

23 March 2020

Electrophilic (het)arenes can undergo reactions with nucleophiles yielding π- or Meisenheimer (σ-) complexes or the products of the SNAr addition/elimination reactions. Such building blocks have only rarely been employed for the design of en...

  • Article
  • Open Access
4 Citations
3,887 Views
12 Pages

18 January 2022

The mechanisms of three selected identity substitution reactions at phosphorus and sulfur occurring with stereospecific inversion have been investigated using density functional theory (DFT). The first identity reaction between methoxyl anion and met...

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