Article
Chemistry, Multidisciplinary
Michael J. Tilby, Damien F. Dewez, Adrian Hall, Carolina Martinez Lamenca, Michael C. Willis
Summary: In this study, the absolute configuration of sulfur-stereogenic aza-sulfur derivatives was determined using a unique feature of sulfonimidamides. Enantioselective alkylation was achieved by generating prochiral ions from sulfonimidamides with the help of a bis-quaternized phase-transfer catalyst. This demonstrates the potential of using configurationally labile aza-sulfur species in asymmetric catalysis.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Applied
Xiaojun Zeng, Xudong Hu, Hanbin Song, Guohua Xia, Zong-Yang Shen, Ronghai Yu, Martin Moskovits
Summary: Zeolites are a class of crystalline nanoporous inorganic materials that have regular micropores and highly tunable functionalities, and microwave technology can efficiently prepare uniform and controllable zeolites with remarkable functions. Current research focuses on the synthesis of zeolites using microwave technologies and their applications, especially in catalysis, gas sensing, CO2 capture, and biomedicine. The future development of this field shows great potential for growth and innovation.
MICROPOROUS AND MESOPOROUS MATERIALS
(2021)
Article
Environmental Sciences
Alessandro Piccolo, Cesar Garcia-Diaz, Vincenza Cozzolino, Marios Drosos, Antonio Scopa, Massimiliano Valentini
Summary: An O-alkylation reaction using tetrabutylammonium hydroxide (TBAH) as a phase-transfer agent was employed to modify the hydrophobic properties of humic acid (HA). The carboxyl and hydroxyl functional groups of HA acted as nucleophiles in substitution reactions with alkyl halides. The findings indicate that the hydrophobicity of humic substances can be modulated through a mild O-alkylation reaction, and this structural modification may have various chemical, environmental, and biological applications.
Article
Chemistry, Multidisciplinary
Zhibin Guo, Daehyun Oh, Min Sagong, Jewon Yang, Geumwoo Lee, Hyeung-geun Park
Summary: An efficient method for synthesizing chiral malonates was established using enantioselective phase transfer catalysis. The a-alkylation reaction of 2,2-diphenylethyl tert-butyl a-methylmalonates with (S,S)-3,4,5-trifluorophenyl-NAS bromide as a phase-transfer catalyst successfully yielded corresponding a-methyl-a-alkylmalonates. These compounds are versatile chiral building blocks with a quaternary carbon center, obtained in high chemical yields (up to 99%) and excellent enantioselectivities (up to 98% ee). Selective hydrolysis of a,a-dialkylmalonates to the corresponding chiral malonic monoacids was achieved using basic (KOH/MeOH) and acidic conditions (TFA/CH2Cl2), demonstrating the practicality of the method.
FRONTIERS IN CHEMISTRY
(2023)
Article
Biochemistry & Molecular Biology
Anna S. Tovmasyan, Anna F. Mkrtchyan, Hamlet N. Khachatryan, Mary V. Hayrapetyan, Robert M. Hakobyan, Artavazd S. Poghosyan, Avetis H. Tsaturyan, Ela V. Minasyan, Victor I. Maleev, Vladimir A. Larionov, Armen G. Ayvazyan, Norio Shibata, Giovanni N. Roviello, Ashot S. Saghyan
Summary: A new family of Cu(II) and Ni(II) salen complexes was synthesized and characterized. These complexes were evaluated for their catalytic activity in the C-alpha-alkylation reaction of Schiff bases. It was found that introducing a chlorine atom into the phenyl ring of the substrate increased both the chemical yield and asymmetric induction. The highest enantiomeric excess was achieved using a Cu(II) salen complex based on (S,S)-cyclohexanediamine and salicylaldehyde at -20 degrees C. Bulky substituents in the ligand led to a decrease in both the enantioselectivity and chemical yield, with complete loss of stereoselectivity achieved with certain substituents at positions 3 and 5 of the phenyl ring.
Article
Biochemistry & Molecular Biology
Kristina Karale, Martin Bollmark, Rouven Stulz, Dmytro Honcharenko, Ulf Tedebark, Roger Stromberg
Summary: This study reported for the first time the synthesis of 2'-O-(N-(aminoethyl)carbamoyl)methyl-modified 5-methyluridine (AECM-MeU) and 5-methylcytidine (AECM-MeC) phosphoramidites in multigram quantities. By optimizing synthesis steps and work-up strategies, large-scale production was achieved with significantly reduced chromatographic purification steps.
Article
Biochemistry & Molecular Biology
Patryk Niedbala, Maciej Majdecki, Piotr Grodek, Janusz Jurczak
Summary: This work describes the development of a highly optimized method for generating quaternary stereogenic centers in beta-keto esters. The method utilizes a phase-transfer alkylation reaction catalyzed by hybrid Cinchona catalysts, resulting in efficient generation of optically active products with excellent enantioselectivity using only 1 mol% catalyst.
Article
Chemistry, Physical
Julia A. Turner, Nicholas Rosano, Daniel J. Gorelik, Mark S. Taylor
Summary: The combined action of a photoredox catalyst, a hydrogen atom transfer mediator, and a hydrogen bond acceptor cocatalyst has been used to successfully transform pyranoside-derived esters into ketodeoxysugars, which are important precursors for synthesizing rare sugar components. Computational studies support a radical lyase-like mechanism for this transformation involving 1,2-acyloxy migration in the radical intermediate.
Review
Chemistry, Physical
Ana Maria Faisca Phillips, Armando J. L. Pombeiro
Summary: Hantzsch esters have emerged as versatile reagents for enantioselective organic transformations in the last century. They can selectively reduce various multiple bonds, such as C=C and C=N, as hydride transfer agents under mild reaction conditions. Additionally, they are effective for the dearomatization of heteroaromatic substances and can participate in cascade processes. In recent years, they have also been employed in photoredox reactions, acting as sacrificial electron and hydrogen donors, as well as alkyl or acyl radical transfer agents.
Article
Biochemistry & Molecular Biology
Karima Belkhadem, Yihong Cao, Rene Roy
Summary: Vanillin-based lactoside derivatives were synthesized using phase-transfer catalyzed reactions from per-O-acetylated lactosyl bromide. The structure was further modified through various reactions to generate analogs with different functionalities.
Article
Chemistry, Physical
Xinyan Lv, Yaohang Cheng, Yingxiao Zong, Qingyun Wang, Guanghui An, Junke Wang, Guangming Li
Summary: In this study, a visible-light-mediated Ru-catalyzed para-alkylation of anilines was reported. The reaction showed high efficiency and mild conditions, with good functional group tolerance for late-stage functionalization of natural products and drugs.
Article
Chemistry, Organic
Lorenzo Serusi, Antonio Massa, Consiglia Tedesco, Amedeo Capobianco, Laura Palombi
Summary: A highly stereoselective access to 3-sulfinyl-substituted isoindolinones has been achieved by a tandem organocatalytic addition/cyclization reaction, followed by diastereoselective oxidation with MCPBA. Enantioenriched isoindolinone N,S-acetals were obtained through a dynamic kinetic asymmetric transformation induced by a bifunctional chiral thiourea organocatalyst, leading to high diastereocontrol in the subsequent sulfoxidation. Theoretical rationale for the stereoselectivity of the oxidation reaction is provided through DFT calculations.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Changpeng Chen, Wenqing Guo, Deyong Qiao, Shaolin Zhu
Summary: We report a NiH-catalyzed asymmetric migratory hydroalkylation process for the efficient and selective construction of enantioenriched multi-substituted cycloalkanes. Through a dynamic kinetic asymmetric transformation (DYKAT), easily accessible racemic and isomeric mixtures of cycloalkenes could be directly utilized as starting materials, convergently producing highly regio-, diastereo-, and enantioselective chiral 1,2-cis disubstituted cycloalkanes. In addition, prochiral cyclic alkenes can also be employed, delivering chiral 1,2-cis disubstituted cycloalkanes through desymmetrization process.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Shi-Yan Cheng, Jia-Bin Liao, Yu-Mei Lin, Lei Gong
Summary: A highly effective method based on organophotocatalytic synthesis has been developed, enabling the synthesis of various tricyclic heterocycles containing S, O, and N atoms. The study shows excellent selectivity and provides insights into the mechanism, paving the way for the development of cost-effective tandem radical reactions and the synthesis of heterocyclic drugs.
Article
Chemistry, Physical
Melissa Cadena, Roberto Silva Villatoro, Jyoti Shah Gupta, Cody Phillips, Jonathan B. Allen, Hadi D. Arman, Daniel J. Wherritt, Nicholas A. Clanton, Alexander L. Ruchelman, Eric M. Simmons, Albert J. DelMonte, John R. Coombs, Doug E. Frantz
Summary: We have developed a highly selective Pd-catalyzed O-benzylation reaction and identified the formation of a key intermediate through detailed reaction analysis. This method enables the selective O-alkylation of substituted 2-quinolinones with high efficiency using a minimal amount of Pd catalyst.
Article
Chemistry, Inorganic & Nuclear
Gyorgy Keglevich, Nikoletta Harsagi, Petra R. Varga, Bianka Huszar, Reka Henyecz, Nora Z. Kiss, Zoltan Mucsi, Peter Bagi
Summary: The conference proceeding summarizes recent findings on the two-step esterification of phenylphosphonic acid, the hydrolysis of arylphosphonates, the Ni-catalyzed Hirao P-C coupling reaction, the Kabachnik-Fields reaction of carboxylic amides, and the reactions of alpha-hydroxyphosphonates, including their phosphorylation and rearrangement reactions.
PHOSPHORUS SULFUR AND SILICON AND THE RELATED ELEMENTS
(2022)
Article
Chemistry, Inorganic & Nuclear
Nikoletta Harsagi, Nora Zsuzsa Kiss, Peter Abranyi-Balogh, Gyorgy Keglevich
Summary: The preparation of dialkyl phenylphosphonates was evaluated through oxidation of phenyl-H-phosphinates and MW-assisted direct esterification of phenylphosphonic acid. The esterification reactions were carried out under MW irradiation in the presence of an ionic liquid as the catalyst.
PHOSPHORUS SULFUR AND SILICON AND THE RELATED ELEMENTS
(2022)
Article
Chemistry, Inorganic & Nuclear
Nora Zsuzsa Kiss, Nikoletta Harsagi, Gyorgy Keglevich
Summary: This conference proceeding focuses on the use of ionic liquid (IL) promoted microwave (MW) assisted synthesis of phosphinates, and looks towards the synthesis of other phosphinic acid derivatives. Traditional methods involve the use of phosphinic chlorides with alcohols/phenols, thiols or amines, which can be costly and produce hydrochloric acid. By using MW irradiation and ILs as catalysts, a more favorable alternative is offered for the direct reaction of phosphinic acids with nucleophiles to produce phosphinic acid derivatives in varying yields.
PHOSPHORUS SULFUR AND SILICON AND THE RELATED ELEMENTS
(2022)
Article
Chemistry, Inorganic & Nuclear
Nikoletta Harsagi, Betti Szollosi, Petra Regina Varga, Gyorgy Keglevich
Summary: Phosphinic and phosphonic acids can be obtained from their esters through hydrolysis, with the need for appropriate catalysts under certain conditions. Ionic liquids play a crucial role in the transesterification of alkyl phosphinates. Depending on the nature of the ionic liquid, the formation of esters from phenylphosphonates may lead to the fission of the C-O bond.
PHOSPHORUS SULFUR AND SILICON AND THE RELATED ELEMENTS
(2022)
Article
Chemistry, Multidisciplinary
Gyorgy Keglevich, Nikoletta Harsagi, Laszlo Drahos, Nora Zsuzsa Kiss
Summary: Monoalkyl phosphonic derivatives were synthesized by the microwave- and ionic liquid-promoted direct esterification of alkylphosphonic acids. These derivatives were then converted to dialkyl alkylphosphonates using alkyl halides in the presence of triethylamine under solvent-free microwave-assisted conditions. The study also identified a minor disproportionation side reaction and synthesized derivatives with different alkoxy groups.
Editorial Material
Chemistry, Organic
Gyoergy Keglevich
BEILSTEIN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Editorial Material
Biochemistry & Molecular Biology
Gyoergy Keglevich
Article
Chemistry, Organic
Petra Regina Varga, Konstantin Karaghiosoff, Eva Viktoria Sari, Andras Simon, Laszlo Hegedus, Laszlo Drahos, Gyorgy Keglevich
Summary: Diethyl alpha-benzylamino- and alpha-amino-benzylphosphonates obtained by the Kabachnik-Fields reaction were useful intermediates in the synthesis of other derivatives. Acylation of alpha-aminophosphonates with acyl chlorides led to the corresponding N-acyl species existing under a dynamic equilibrium of two conformers. NMR measurements at different temperatures revealed hindered rotation in some derivatives.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Nora Popovics-Toth, Trinh Dang Tran Bao, Adam Tajti, Bela Matravolgyi, Zsolt Kelemen, Franc Perdih, Laszlo Hackler, Laszlo G. Puskas, Erika Balint
Summary: A catalyst-free approach was developed for the synthesis of chromonyl-substituted alpha-aminophosphine oxides. The reaction was carried out at ambient temperature using 3-formyl-6-methylchromone, primary amines, and secondary phosphine oxides. When aliphatic amines or aminoalcohols were used at a higher temperature, phosphinoyl-functionalized 3-aminomethylene chromanones were formed instead. The cytotoxicity of the synthesized compounds was investigated in different cell lines.
Article
Biochemistry & Molecular Biology
Bence Varga, Levente Buna, Daniella Vincze, Tamas Holczbauer, Bela Matravolgyi, Elemer Fogassy, Gyorgy Keglevich, Peter Bagi
Summary: A library of 1-adamantyl arylthiophosphonates was synthesized, and a chiral separation method using (S)-1-phenylethylamine as the resolving agent was developed. Three out of five arylthiophosphonates were obtained in enantiopure form (ee > 99%). The subsequent desulfurization reaction retained the enantiomeric purity of the optically active arylthiophosphonates (ee = 95-98%), providing an alternative method for the preparation of 1-adamantyl aryl-H-phopshinates. The absolute configuration of (S)-1-adamantyl phenylphosphonothioic acid was determined using single-crystal XRD, and the organocatalytic applicability of (S)-1-adamantyl phenylphosphonothioic acid as a P-stereogenic Bronsted acid was evaluated.
Article
Chemistry, Multidisciplinary
Bianka Huszar, Renata Szolga, Szilvia Bosze, Rita Olahne Szabo, Andras Simon, Konstantin Karaghiosoff, Matyas Czugler, Laszlo Drahos, Gyoergy Keglevich
Summary: P-functionalized derivatives of 9-phenyl-9H-carbazole and dihydroindoline were synthesized using microwave irradiation. The products showed significant cytotoxic activity, outperforming the traditional method.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Organic
Bianka Huszar, Zoltan Mucsi, Gyorgy Keglevich
Summary: This study investigated a less-studied variation of the Hirao reaction, which involves the coupling of arylboronic acids with >P(O)H reagents. The reaction was catalyzed by Pd(OAc)2 and the ligand was supplied via its trivalent tautomeric form. The optimal conditions for the synthesis of various phosphine oxide and phosphonate derivatives were explored. The self-assembling ligands around the Pd(2+) center played a crucial role in the mechanism and efficiency of the catalyst.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Editorial Material
Multidisciplinary Sciences
Gyorgy Keglevich
Article
Chemistry, Multidisciplinary
Bettina Ravai, Nora Popovics-Toth, Kinga Komka, Istvan Csontos, Balint Szokol, Zoltan Orfi, Laszlo Orfi, Erika Balint
Summary: A new multicomponent method was developed for the synthesis of benzo[de]isoquinolinones bearing a phosphonate or a phosphine oxide moiety. The synthesis was carried out under mild conditions and the reaction mechanism and cytotoxicity of the compounds were investigated.
REACTION CHEMISTRY & ENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
Gyorgy Keglevich, Nikoletta Harsagi, Sarolta Szilagyi
Summary: A chlorine-free and simple method was developed for the preparation of alkylamino-3-phospholene oxides, and their diastereoselective synthesis was achieved. The interconversion between cyclic phosphinic amides and phosphinates holds significant value.
