Article
Chemistry, Multidisciplinary
Linyi Lai, Mengyuan Liu, Jiayu Liu, Wenhan Li, Wen Miao, Zhaoliang Sun, Zhenyang Wang, Yuangao Wang, Huibing Shi, Chen Chen, Xin Jin, Chaohe Yang
Summary: This study focuses on the kinetic modeling of aqueous glucose oxidation to tartaric acid, comparing the catalytic performances of monometallic Pt/TiO2 and bimetallic AuPt/TiO2 catalysts. The results provide important data for the future development of synthesizing useful carboxylates.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2023)
Article
Thermodynamics
Xuefeng Fan, Wenyu Sun, Zhongkai Liu, Yi Gao, Jiuzhong Yang, Bin Yang, Chung K. Law
Summary: This study investigated the oxidation mechanism of DIPE at different temperatures through experiments and kinetic modeling, revealing that the low oxidation reactivity at lower temperatures is mainly due to radical decomposition reactions, while at higher temperatures, consumption primarily occurs through hydrogen abstraction from carbon atoms. Propylene and acetone are the major products, with other intermediates mainly formed through the consumption of these two species.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Biochemistry & Molecular Biology
Romulo F. Carneiro, Evelyn S. Aguiar, Valdenice F. Santos, Ana L. E. Santos, Maria H. C. Santos, Renato R. Roma, Romerio R. S. Silva, Maria L. M. B. Leal, Livia T. Silva, Bruno A. M. Rocha, Claudio G. L. Silva, Celso S. Nagano, Alexandre H. Sampaio, Racquel O. S. Souza, Claudener S. Teixeira
Summary: The research focused on the structure-function study of plant lectins, particularly in elucidating their mechanisms in cell models. The results showcased the amino acid sequencing, three-dimensional structure prediction, and inhibitory effect of P. pendula lectin on Leishmania infantum promastigote development. The study confirmed the leishmanicidal potential of PpeL, suggesting its utility as a new strategy for antileishmanial drug development.
PROCESS BIOCHEMISTRY
(2021)
Article
Biochemistry & Molecular Biology
Mariam Tahoun, Marianne Engeser, Luca Svolacchia, Paul Martin Sander, Christa E. E. Mueller
Summary: This study investigates the stability and degradation of the oxygen-complexing prosthetic group of hemoglobin, heme, under various conditions expected to occur during fossilization. The results reveal that heme is most stable under anaerobic reductive conditions and least stable in the presence of H2O2. The presence of oxygen and H2O2 leads to the cleavage of heme and the formation of hematinic acid. The role of iron cation in heme degradation is confirmed, as heme lacking iron remains more stable. This study provides valuable insights into the fate of heme during fossilization.
Article
Chemistry, Organic
Jun Ueda, Shingo Harada, Mayu Kobayashi, Mai Yanagawa, Tetsuhiro Nemoto
Summary: A dual catalyst system consisting of maleic acid and Schreiner's thiourea was used to successfully synthesize a spiroindolenine core, providing a new approach for synthetic strategies that were previously difficult to achieve. Computational studies revealed a unique macrocyclic transition state that lowered the activation energy of the spirocyclization reaction.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Food Science & Technology
Xiaofei Yang, Zongyuan Han, Tianshuang Xia, Yaping Xu, Zhaoxia Wu
Summary: During microwave heating, edible oils undergo oxidation, affecting their nutritional value and safety. Researching the oxidation mechanisms of unsaturated fatty acids in these oils is important for determining their suitability for microwave heating. An analysis of four common vegetable cooking oils showed that sunflower oil is the most suitable for daily microwave heating, based on changes in acid values, malondialdehyde concentrations, and fatty acid composition during microwave treatment. Monitoring three characteristic functional groups can help track the oxidative changes in oils.
LWT-FOOD SCIENCE AND TECHNOLOGY
(2021)
Article
Chemistry, Physical
Qi Zhang, Siru Ren, Chenming Gu, Ang Li, Song Xue
Summary: This study introduces a systematic approach to improve the enantioseparation performance of tartaric acid in capillary electrophoresis using ionic liquid technology. It found that achiral ILs exhibit better performance when combined with tartaric acid compared to chiral ILs.
JOURNAL OF MOLECULAR LIQUIDS
(2021)
Article
Chemistry, Multidisciplinary
Lucia Veltri, Roberta Amuso, Paola Vitale, Maria A. Chiacchio, Cinzia Benincasa, Bartolo Gabriele
Summary: A new process has been developed for the high value added conversion of carbon dioxide to 1,3-oxazine-2,4-diones through catalytic carboxylative heterocyclization of readily available 3-ynamides, yielding products in 44-85% yields under relatively mild conditions.
JOURNAL OF CO2 UTILIZATION
(2021)
Article
Biochemistry & Molecular Biology
Matthias Brauser, Tim Heymann, Christina Marie Thiele
Summary: In this study, the intermediate responsible for the acyl transfer in a highly enantioselective tetrapeptide organocatalyst was successfully detected and characterized using NMR-spectroscopy and mass spectrometry. The formation of complexes between the tetrapeptide and trans-cyclohexane-1,2-diols was also observed, along with monitoring of the acetylation reaction. These findings provide important insights into the understanding of this organocatalyst's mechanism.
Article
Chemistry, Multidisciplinary
Roderick Corstiaan Abraham Versloot, Patricia Arias-Orozco, Matthijs Jonathan Tadema, Florian Leonardus Rudolfus Lucas, Xinghong Zhao, Siewert J. J. Marrink, Oscar Paul Kuipers, Giovanni Maglia
Summary: Mass spectrometry cannot distinguish between molecules with the same mass-to-charge ratio, but nanopore technology can differentiate diastereomeric and enantiomeric differences in peptides that cannot be observed by conventional MS analysis. The resolution in nanopore analysis is likely due to multiple chiral interactions during peptide transport across the nanopore, similar to chiral chromatography. Nanopore technology also offers possibilities for the rapid and cost-effective analysis of peptides, including those that cannot be easily differentiated by mass spectrometry.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Multidisciplinary Sciences
Sarah E. Biehn, Steffen Lindert
Summary: HRPF combined with mass spectrometry can reveal protein structure, while a dynamics-driven algorithm can enhance the accuracy of structure prediction.
NATURE COMMUNICATIONS
(2021)
Article
Energy & Fuels
Dong Guan, Zhengyu Chen, Xiu Chen, Ying Zhang, Qiuyan Qi, Quan Shi, Suoqi Zhao, Chunming Xu, Linzhou Zhang
Summary: This paper focuses on constructing a heavy petroleum compositional model and hydrotreating process model with a more accurate molecular detail using high-resolution mass spectrometry data. Over 12,000 representative molecules were constructed to form a heavy petroleum molecular structure library, and 18 reaction rules were formulated to express the molecular conversion pathways. The model parameters were globally optimized according to experimental data, showing good agreement with bulk property data and high-resolution mass spectrometry data.
Article
Thermodynamics
Jin-Tao Chen, Zhi-Hao Jin, Wang Li, Kai-Ru Jin, Shu-Bao Song, Jiu-Zhong Yang, Zhen-Yu Tian
Summary: The pyrolysis of benzyl alcohol was studied in a flow tube reactor under different pressures, revealing that H-abstraction reactions with H atoms and OH radicals are the main consumption pathway. Various factors affect the pyrolysis and oxidation processes of benzyl alcohol, providing a theoretical basis for further research on combustion chemical kinetics.
COMBUSTION AND FLAME
(2021)
Article
Chemistry, Multidisciplinary
Nikolaos F. F. Nikitas, Elpida Skolia, Petros L. L. Gkizis, Ierasia Triandafillidi, Christoforos G. G. Kokotos
Summary: Since the United Nations set goals dealing with climate change, the chemical industry has focused on recycling already-used polymers, targeting the re-insertion of plastic waste to market via reforming. Upcycling of polystyrene plastic waste is gaining popularity in plastic upconversion research. A novel, green, organocatalytic and photochemical aerobic upcycling process of polystyrene to benzoic acid has been successfully developed and applied to daily-life used polystyrene products, resulting in yields ranging from 25% to 58%. Moreover, the upcycled product obtained from polystyrene materials has been utilized in the synthesis of bioactive molecules, such as acetylsalicylic acid.
Article
Engineering, Chemical
Mengyuan Liu, Linyi Lai, Zhenyang Wang, Xin Jin, Jian Shen, Yuangao Wang, Quanxing Zhang, Dongpei Zhang, Yu Sun, Hui Ning, Wenting Wu, Guangyu Zhang, Chaohe Yang
Summary: In this study, the plausible reaction mechanism for activation of -CHO and -COOH groups in glucose and gluconic acid molecules using bimetallic AuPt/TiO2 catalysts has been revealed through UV-vis technique. The bimetallic catalysts selectively promote C-H and C-C cleavage reactions through extraction and coordination mechanisms. High conversion rates of glucose and gluconic acid to tartaric acid (TA) were achieved with AuPt/TiO2 catalysts, resulting in record high TA production rates.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
Article
Chemistry, Organic
Victoria Haider, Paul Zebrowski, Jessica Michalke, Uwe Monkowius, Mario Waser
Summary: This study presents an enantioselective electrophilic alpha-selenation method using Cinchona alkaloids as organocatalysts, leading to the synthesis of a variety of differently substituted derivatives with reasonable levels of enantioselectivities. Further investigations on the stability and suitability of these compounds for further manipulations have also been carried out.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2022)
Review
Chemistry, Organic
Raghunath Chowdhury, Akhil K. Dubey, Mario Waser
Summary: Asymmetric decarboxylative aldol reactions of MAHTs, MAHOs, and beta-ketoacids with different carbonyl compounds are valuable transformations for the direct synthesis of enantio-enriched beta-hydroxy esters and ketones. Organocatalysis and metal catalysis are the leading strategies for carrying out these reactions in recent progress.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Mario Waser, Michael Winter, Christopher Mairhofer
Summary: This article introduces the significance of (thio)-urea-containing bifunctional quaternary ammonium salts as organocatalysts and their application in asymmetric method development. It provides an overview of catalyst design and highlights the author's own contributions.
Review
Chemistry, Organic
Olga Garcia Mancheno, Mario Waser
Summary: Since the early reports by von Liebig, Knoevenagel and Bredig, asymmetric organocatalysis has come a long way, culminating in the 2021 Nobel Prize in Chemistry. This Perspective provides a brief introduction by discussing the historical development, classical methods, and selected advanced recent examples that have opened new directions in this growing field.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Lorenzo Serusi, Paul Zebrowski, Johannes Schorgenhumer, Antonio Massa, Mario Waser
Summary: We describe a protocol for the asymmetric aldol-initiated cascade addition of isoxazolidin-5-ones to ortho-cyanobenzaldehydes using Takemoto's bifunctional organocatalyst. This method allows for the synthesis of novel beta(2,2)-amino acid-phthalide conjugates with good enantio- and diastereoselectivities in reasonable yields, and the subsequent ring-opening of these compounds to acyclic carboxylic acid derivatives was demonstrated.
HELVETICA CHIMICA ACTA
(2022)
Article
Chemistry, Organic
Paul Zebrowski, Katharina Roeser, Daniel Chrenko, Jiri Pospisil, Mario Waser
Summary: The enantioselective addition of isoxazolidin-5-ones to the α-carbon of allenoates has been achieved using a novel spirobiindane-based quaternary ammonium salt catalyst under classical liquid-solid phase-transfer conditions. This method provides unprecedented highly functionalized β(2,2)-amino acid derivatives with good enantioselectivities and high yields. Further manipulations of the products have also been conducted.
SYNTHESIS-STUTTGART
(2023)
Article
Biochemistry & Molecular Biology
Luka Ciber, Franc Pozgan, Helena Brodnik, Bogdan Stefane, Jurij Svete, Mario Waser, Uros Groselj
Summary: Ten novel bifunctional quaternary ammonium salt phase-transfer organocatalysts were synthesized and evaluated for their organocatalytic activity in electrophilic heterofunctionalizations and the Michael addition reaction. The reactions showed high conversion rates, but low enantioselectivities. The catalysts were fully characterized and the stereochemistry at the C-2 chiral center was determined.
Article
Chemistry, Applied
Christopher Mairhofer, Mario Waser
Summary: Dibenzoylperoxide was found to be a versatile oxidant for reactions of phenol derivatives with NaN3 catalyzed by quaternary ammonium iodide or bromide. The use of iodides allowed for efficient benzylic azidations, while the use of bromides allowed for dearomative azidations. Both methods have been successfully applied to various phenol derivatives, and an enantioselective variant using chiral quat. ammonium bromides has been demonstrated.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Correction
Biochemistry & Molecular Biology
Guglielmo Monaco, Maximilian Tiffner, Antonia Di Mola, Wouter Herrebout, Mario Waser, Antonio Massa
Article
Chemistry, Organic
David Weinzierl, Magdalena Piringer, Paul Zebrowski, Lotte Stockhammer, Mario Waser
Summary: Enantioselective synthesis of alpha-chlorinated carboxylic acid esters was achieved with er up to 99:1 and yields up to 82% via a one-pot multistep protocol starting from alpha-diazoketones. This process involves a photochemical Wolff rearrangement, enantioselective alpha-chlorination using a chiral Lewis base catalyst, and a final nucleophilic displacement of the bound catalyst. The resulting products were successfully used for stereospecific nucleophilic displacement reactions with N- and S-nucleophiles.
Article
Chemistry, Organic
Christopher Mairhofer, Katharina Roeser, Meysam Aryafard, Markus Himmelsbach, Mario Waser
Summary: We have developed a protocol for the alpha-thio- and alpha-seleno-cyanation of cyclic beta-ketoesters and oxindoles using NaSCN or KSeCN as inorganic nucleophilic S(e)CN sources. The key to the success of this transformation is the use of dibenzoylperoxide as an oxidant, enabling the coupling of two nucleophilic species under simple operation conditions with high yields and broad functional group tolerance.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Lotte Stockhammer, Maximilian Radetzky, Syeda Sadia Khatoon, Matthias Bechmann, Mario Waser
Summary: A two-step protocol for the asymmetric synthesis of novel chiral benzofused ε-lactones starting from O-protected hydroxymethyl-para-quinone methides and activated aryl esters is reported. The use of chiral isothiourea Lewis base catalysts allows the obtaining of a broad variety of differently substituted products with high levels of enantioselectivities.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Biochemistry & Molecular Biology
Antonia Di Mola, Giorgia Nicastro, Lorenzo Serusi, Rosanna Filosa, Mario Waser, Antonio Massa
Summary: Here, we report the efficient application of a K2CO3 promoted cascade reaction in synthesizing novel 3-methylated analogs of Pazinaclone and PD172938, belonging to the isoindolinone heterocyclic class. Organocatalytic asymmetric synthesis of key intermediate and its transformation into highly enantioenriched 3-methylated analog of (S)-PD172938 was also developed. These achievements are particularly significant for medicinal chemistry, as the methyl group serves as a valuable structural modification in the rational design of new and more effective bioactive compounds.
Article
Chemistry, Organic
Katharina Roeser, Anna Scheucher, Christopher Mairhofer, Matthias Bechmann, Mario Waser
Summary: This study demonstrates the use of quaternary ammonium iodides as catalysts for the direct conversion of readily available beta-ketolactones into dihydrobenzofurans under oxidative conditions, via a decarboxylative oxidative cycloetherification sequence facilitated by an in situ formed ammonium hypoiodite species.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Paul Zebrowski, Isabella Eder, Andreas Eitzinger, Sharath Chandra Mallojjala, Mario Waser
Summary: The enantioselective synthesis of novel differently functionalized alpha-halogenated alpha-aryl-beta 2,2-amino acid derivatives was achieved using an ammonium-salt-catalyzed asymmetric alpha-halogenation of isoxazolidin-5-ones. The use of Maruoka's spirocyclic binaphthyl-based ammonium salts and detailed mechanistic studies revealed the key features for the catalyst-substrate interactions.
ACS ORGANIC & INORGANIC AU
(2022)
