Helvetica Chimica Acta最新文献_第2页

Iron-Catalyzed C–H Activation/Aza-Annulation with 2-Butyne for Accessing Methylated Aza-Arenes 铁催化C-H活化/ 2-丁炔环化氮杂芳烃的研究

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2025-01-22 DOI: 10.1002/hlca.202400200

Yan Zhang, Rui Shang, Eiichi Nakamura

{"title":"Iron-Catalyzed C–H Activation/Aza-Annulation with 2-Butyne for Accessing Methylated Aza-Arenes","authors":"Yan Zhang, Rui Shang, Eiichi Nakamura","doi":"10.1002/hlca.202400200","DOIUrl":"https://doi.org/10.1002/hlca.202400200","url":null,"abstract":"The incorporation of methyl groups into aza-arene frameworks not only often improves their biological activity as the “magic methyl” effect, but also notably affects their solid-state electronic properties by modulating π-π stackings, which makes them promising candidates for developing organic electronic materials. This study focuses on the iron-catalyzed C−H annulation of ketones with 2-butyne via their oxime ethers, offering an efficient pathway to synthesizing methylated π-extended aza-arenes. The reactions utilize isobutyl aluminum(III) catecholate as a base and Triphos (bis(2-diphenylphosphinoethyl)phenylphosphine) as a ligand. Reported C−H activation methods using rhodium catalysis proved less effective with π-conjugated substrates. Regioselective C−H aza-annulation with 1-(trimethylsilyl)propyne following desilylation provides also mono-methylated azaarenes. The reactions also generate tetra-methylated aza-arene products by two-fold C−H aza-annulation on chromeno[3,2-a]xanthene-13,14-dione and quinacridone. These methylated aza-arenes exhibit strong π-π stacking, a narrow emission band, and tunable photophysical properties, indicating their potential applications as electronic materials.","PeriodicalId":12842,"journal":{"name":"Helvetica Chimica Acta","volume":"108 4","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hlca.202400200","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143840595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Cover Picture: (Helv. Chim. Acta 1/2025) 封面图片：（Helv.）詹。Acta 1/2025)

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2025-01-17 DOI: 10.1002/hlca.202570101

引用次数: 0

Amoxicillin Concentrations in Samples of Musculoskeletal Infections 肌肉骨骼感染样品中的阿莫西林浓度

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2025-01-13 DOI: 10.1002/hlca.202400178

Joana Erdmann, Richard Kuehl, Mario Morgenstern, Dirk Bumann, Martin Clauss, Nina Khanna, Katharina M. Rentsch

{"title":"Amoxicillin Concentrations in Samples of Musculoskeletal Infections","authors":"Joana Erdmann, Richard Kuehl, Mario Morgenstern, Dirk Bumann, Martin Clauss, Nina Khanna, Katharina M. Rentsch","doi":"10.1002/hlca.202400178","DOIUrl":"https://doi.org/10.1002/hlca.202400178","url":null,"abstract":"Amoxicillin is a frequently used beta-lactam antibiotic and at the same time a fragile analyte. Aim of this work was to investigate the sensitive properties of amoxicillin in biological samples and validate a quantification method for amoxicillin in soft tissue samples. Simple protein precipitation and 2D-High performance liquid chromatography coupled to tandem mass spectrometry was used for sample preparation and analysis. The formation of a covalent amoxicillin methanol-adduct could be observed in varying extents depending on matrix and sample preparation method. In-Source Products (ISPs) were investigated in plasma, soft tissue, and water and no differences could be observed. We successfully validated a method for amoxicillin determination in tissue samples using the sum of 2 ISPs of amoxicillin for quantification. 37 study samples of different deep-seated infections could be analyzed. Measured amoxicillin concentrations ranged from below 0.5 mg/kg up to 87 mg/kg. Concentrations in abscesses were lower than in other infections.","PeriodicalId":12842,"journal":{"name":"Helvetica Chimica Acta","volume":"108 2","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hlca.202400178","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143423541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Threshold Photoelectron Spectrum of 3,4-Dimethylenecyclobutene 3,4-二亚甲基环丁烯的阈值光电子谱

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2025-01-11 DOI: 10.1002/hlca.202400197

Emil Karaev, Dorothee Schaffner, Marius Gerlach, Tobias Preitschopf, Patrick Hemberger, Ingo Fischer

引用次数: 0

Effect of π-Electron Conjugation on the Chiroptical Properties of Helicene Carbon Nanohoops π-电子共轭对螺旋碳纳米环热学性能的影响

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2025-01-10 DOI: 10.1002/hlca.202400166

Kovida Kovida, Juraj Malinčík, Tomáš Šolomek

引用次数: 0

Neutralization of an Oxytocin Derivative by 355 nm Photocleavage in High Vacuum 高真空355nm光裂解中和催产素衍生物

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2024-12-25 DOI: 10.1002/hlca.202400167

Yong Hua, Daniel Häussinger, Marcel Mayor, Valentin Köhler, Marcel Strauss, Martin F. X. Mauser, Tim Kostersitz, Philipp Geyer, Markus Arndt

引用次数: 0

Single Molecule Conductance of Anthraquinone-Based Molecular Wire: Effect of the Anchoring Group 蒽醌类分子线的单分子电导：锚定基团的影响

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2024-12-23 DOI: 10.1002/hlca.202400155

František Vavrek, Jindřich Gasior, Jakub Šebera, Michal Valášek, Gábor Mészáros, Magdaléna Hromadová

{"title":"Single Molecule Conductance of Anthraquinone-Based Molecular Wire: Effect of the Anchoring Group","authors":"František Vavrek, Jindřich Gasior, Jakub Šebera, Michal Valášek, Gábor Mészáros, Magdaléna Hromadová","doi":"10.1002/hlca.202400155","DOIUrl":"https://doi.org/10.1002/hlca.202400155","url":null,"abstract":"Functional molecular electronics require molecular design that provides integrity and stability. In this work, we explored two types of single molecule devices differing in anchoring to the conducting leads. Single molecule conductance was measured by STM break junction method and the molecular conductor was composed of the redox active anthraquinone center (switching element) containing either 4-pyridyl or p-phenylene thioacetate anchoring groups. The experimental results were supported by quantum chemical charge transport calculations. Molecular junctions containing 4-pyridyl anchors displayed two stable configurations with conductance values of 4.9 nS and 20 pS, respectively. Molecules anchored via p-phenylene thioacetate groups led to one main junction configuration with conductance of 0.1 nS. Junctions employing 4-pyridyl anchoring groups had higher junction formation probability, which in combination with lower conductance makes them better candidates for switching purposes.","PeriodicalId":12842,"journal":{"name":"Helvetica Chimica Acta","volume":"108 2","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hlca.202400155","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143424136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Crystal Structure of an Oligoproline Hexamer with a Zig-zag Arrangement 低聚脯氨酸六聚体之字形排列的晶体结构

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2024-12-23 DOI: 10.1002/hlca.202400147

Tobias Schnitzer, Joseph F. Woods, Nils Trapp, Helma Wennemers

引用次数: 0

NMR Investigation of Lanthanoid (III) Complexes of bbppn (H2bbppn: N,N’-bis(2-hydroxybenzyl)-N,N’-bis(2-methylpyridyl)propylene-1,2-diamine) bbppn类镧（III）配合物（H2bbppn: N，N′-双（2-羟基苄基）-N，N′-双（2-甲基吡啶基）丙烯-1,2-二胺）的NMR研究

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2024-12-23 DOI: 10.1002/hlca.202400177

Annika Matt, Alessandro Prescimone, Daniel Häussinger

{"title":"NMR Investigation of Lanthanoid (III) Complexes of bbppn (H2bbppn: N,N’-bis(2-hydroxybenzyl)-N,N’-bis(2-methylpyridyl)propylene-1,2-diamine)","authors":"Annika Matt, Alessandro Prescimone, Daniel Häussinger","doi":"10.1002/hlca.202400177","DOIUrl":"https://doi.org/10.1002/hlca.202400177","url":null,"abstract":"Pseudocontact shift NMR spectroscopy is a powerful tool in integrative structural biology. Conformationally rigid, enantiopure chelators with extremely high affinity to lanthanoids play a crucial role for this technique. In this context, we have synthesized enantiopure complexes of Y, Eu, Dy, Tm and Lu of (S)-H2bbppn (H2bbppn: N,N’-bis(2-hydroxybenzyl)-N,N’-bis(2-methylpyridyl)propylene-1,2-diamine) and investigated their NMR properties. Strongly paramagnetic 1H-NMR spectra showing extremely large chemical shift ranges were obtained for Dy (2280 ppm), Tm (380 ppm) and Eu (68 ppm) and the anisotropy of the magnetic susceptibility was determined in all cases. The axial components of the susceptibility tensors for the (S)-bbppn complexes were determined as 225, −32 and 6×10−32 m3 for Dy, Tm and Eu. For (S)-[Y(bbppn)Cl], a single crystal structure was obtained providing atom coordinates for the isostructural series of lanthanoid compounds. It was demonstrated that in all cases rigid, enantiopure lanthanoid complexes were formed, providing an attractive new scaffold for potential conjugatable lanthanoid chelating tags.","PeriodicalId":12842,"journal":{"name":"Helvetica Chimica Acta","volume":"108 4","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143840650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Development of a Safe and Efficient Continuous Flow Method for the Synthesis of 3-Difluoromethoxypyridine Derivatives 一种安全高效的3-二氟甲氧基吡啶衍生物连续流合成方法的建立

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2024-12-16 DOI: 10.1002/hlca.202400182

Hansjoerg Lehmann, Thomas Ruppen, Susanne Oswald, Ning Ye, Xiangguang Tian, Xingxian Gu, Chunhui Dai, Robin A. Fairhurst

引用次数: 0