Helvetica Chimica Acta最新文献_第5页

Potential of miRNA as Imaging Targets for PET miRNA 作为 PET 成像靶点的潜力

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2024-07-09 DOI: 10.1002/hlca.202400014

Simon H. Zientek, Stephen Thompson, Franklin I. Aigbirhio, Selena Milicevic Sephton

{"title":"Potential of miRNA as Imaging Targets for PET","authors":"Simon H. Zientek, Stephen Thompson, Franklin I. Aigbirhio, Selena Milicevic Sephton","doi":"10.1002/hlca.202400014","DOIUrl":"10.1002/hlca.202400014","url":null,"abstract":"Positron Emission Tomography (PET) is an important part of the medical imaging field which is continually exploring novel biological targets as exemplified by PET imaging of neuroinflammation. Due to limitations stemming from either sub-optimal biological targets or a lack of available selective radiotracers, alternative biomarkers and PET imaging agent candidates are considered. One such possible target is microRNA (miRNA) and herein, we discuss the potential of miRNA for PET imaging. With the aim of addressing key strategies for imaging miRNA with PET, we identify three distinct approaches as follows: small molecules directly targeting miRNA, small molecules indirectly targeting Argonaute 2 (AGO2)-protein complexes, and direct chemical modification of antisense oligonucleotides. The radiosynthetic approaches are based on the methods of direct radiolabelling of respective antisense oligonucleotides and several examples are described herein, showcasing the potential of miRNA in PET imaging. Whilst these approaches offer different radiolabelling strategies, application of these radiolabelled molecules towards PET imaging of miRNA are scarce with only one, limited example applied to bone remodeling reported in the literature.","PeriodicalId":12842,"journal":{"name":"Helvetica Chimica Acta","volume":"107 8","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hlca.202400014","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141577339","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

Platinum-Catalyzed Isomerization of Cyclopropenes to 1,3-Dienes 铂催化环丙烯与 1,3-二烯的异构化反应

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2024-07-05 DOI: 10.1002/hlca.202400105

Vladyslav Smyrnov, Antonin Homassel, Leander Choudhury, Jerome Waser

引用次数: 0

Fluorinated-Thiolate Osmium(III) and Osmium(IV) Complexes Bearing N,N-diethyldithiocarbamate and Substituted Phosphines. Synthesis, Crystal Structures and DFT-Studies 含 N,N-二乙基二硫代氨基甲酸酯和取代膦的氟硫酸盐锇(III)和锇(IV)配合物：合成、晶体结构和 DFT 研究

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2024-07-05 DOI: 10.1002/hlca.202400066

Bertín Anzaldo, Andrés Álvarez-García, Sylvain Bernès, Armando Ramírez-Monroy, Maribel Arroyo-Carranza

{"title":"Fluorinated-Thiolate Osmium(III) and Osmium(IV) Complexes Bearing N,N-diethyldithiocarbamate and Substituted Phosphines. Synthesis, Crystal Structures and DFT-Studies","authors":"Bertín Anzaldo, Andrés Álvarez-García, Sylvain Bernès, Armando Ramírez-Monroy, Maribel Arroyo-Carranza","doi":"10.1002/hlca.202400066","DOIUrl":"10.1002/hlca.202400066","url":null,"abstract":"The paramagnetic osmium(III) [Os(SRF)(S2CNEt2)2(P(C6H4X-4)3)] (RF=C6F4H−4, C6F5; X=OCH3, CH3, F) (1–6) along with diamagnetic osmium(IV) [Os(SRF)2(S2CNEt2)2] (7–8) complexes were obtained from [Os(SRF)4(P(C6H4-X)3)] and NaS2CNEt2, which were characterized by FAB mass spectrometry, IR spectroscopy, single crystal X-ray diffraction, and for the diamagnetic 7 also by NMR. TD-DFT calculations were performed to simulate the absorption spectra of complexes. In the visible region, LMCT transitions contribute to the calculated intensities, which are somewhat related to the color of the synthesized compounds. In the ultraviolet region, the phosphine ligand plays a significant role in MLCT transitions, which results in Os(III) complexes exhibiting an intense band in that region. Topological analysis and electron localization function (ELF) maps calculated for 6 and 7 confirm the strong ionic character of the Os−S coordination bonds formed by the thiophenolate and dithiocarbamate ligands. This comprehensive study provides information on the structure, bonding, and electronic properties of osmium complexes, for potential applications in catalysis, materials science, and biological systems.","PeriodicalId":12842,"journal":{"name":"Helvetica Chimica Acta","volume":"107 9","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141577341","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

En Route to Enantioenriched Quaternary Stereocenters via Lewis Base/Palladium Cooperative Catalysis 通过路易斯碱/钯合作催化获得对映富集季立体中心的途径

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2024-06-27 DOI: 10.1002/hlca.202400089

Maygan M. McGuire, Andrew C. Bach, Maren Pink, Thomas N. Snaddon

引用次数: 0

Cost-Effective and Scalable Enzyme-Mediated Preparation of Short-Chain Primary Amines 经济高效、可扩展的酶介导短链伯胺制备技术

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2024-06-27 DOI: 10.1002/hlca.202400078

Stefania Gianolio, Beatrice Rassati, Francesca Paradisi

{"title":"Cost-Effective and Scalable Enzyme-Mediated Preparation of Short-Chain Primary Amines","authors":"Stefania Gianolio, Beatrice Rassati, Francesca Paradisi","doi":"10.1002/hlca.202400078","DOIUrl":"10.1002/hlca.202400078","url":null,"abstract":"Amines, crucial components in various industries, play a pivotal role in the synthesis of pharmaceuticals, agrochemicals, and specialty chemicals. Recognizing the environmental impact of conventional methods for their preparation, our study centers on the utilization of abundantly available natural molecules, specifically amino acids, as precursors for short chain amine synthesis. This paper focuses on the biocatalyst, L-valine decarboxylase from Streptomyces viridifaciens (VlmD), delving into the substrate scope, catalytic activity, and cost-effective scalability of an enzymatic process for amine synthesis. Additionally, we investigate the feasibility of immobilizing VlmD, aiming to pave the way for its effective use in industrial applications. Our study exploits the SpinChem system and provides a comprehensive understanding of the potential and limitations of this biocatalyst. Notably, our yields for key amines (8.42 g ⋅ d−1 for isobutylamine, 5.23 g ⋅ d−1 for isoamylamine, 5.16 g ⋅ d−1 for (S)-2-methylbutylamine, 3.78 g ⋅ d−1 for 3-(methylthio)propylamine, and 10.52 g ⋅ d−1 for (R)-1-amino-2-propanol) demonstrate the process efficiency and potential for industrial scalability.","PeriodicalId":12842,"journal":{"name":"Helvetica Chimica Acta","volume":"107 8","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hlca.202400078","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141509277","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 Novel, Industrially-feasible Synthetic Route to (+)-Biotin from L-Cysteine 从 L-半胱氨酸合成 (+)- 生物素的新颖、工业上可行的合成路线

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2024-06-20 DOI: 10.1002/hlca.202400090

Qiongmei Zhang, Kun Peng, Werner Bonrath, Zili Zhang, Zhibin Zhu, Yuehan Xing, Xiaoyan Wang, Bo Gao, Jonathan A. Medlock

引用次数: 0

The Relation between Nature and Stability of H2-Dissociating Sites and Propene Selectivity in Silica-Supported (Ga,Al)2O3 Mixed Oxide Propane Dehydrogenation Catalysts 二氧化硅支撑（Ga,Al）2O3 混合氧化物丙烷脱氢催化剂中 H2 分解位点的性质和稳定性与丙烯选择性之间的关系

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2024-06-18 DOI: 10.1002/hlca.202400076

Pedro Castro-Fernández, Alexander I. Serykh, Melis Yarar, Deni Mance, Paula M. Abdala, Christophe Copéret, Alexey Fedorov, Christoph R. Müller

{"title":"The Relation between Nature and Stability of H2-Dissociating Sites and Propene Selectivity in Silica-Supported (Ga,Al)2O3 Mixed Oxide Propane Dehydrogenation Catalysts","authors":"Pedro Castro-Fernández, Alexander I. Serykh, Melis Yarar, Deni Mance, Paula M. Abdala, Christophe Copéret, Alexey Fedorov, Christoph R. Müller","doi":"10.1002/hlca.202400076","DOIUrl":"https://doi.org/10.1002/hlca.202400076","url":null,"abstract":"Colloidal solutions of gallia-alumina (Ga,Al)2O3(x:y) solid-solution nanoparticles with nominal atomic Ga : Al (x:y) ratios of 1 : 6, 1 : 3, 3 : 1, and 1:0 were used to prepare silica-supported catalysts for propane dehydrogenation (PDH). A comparison of the unsupported and silica-supported catalysts reveals that the dispersion on silica increases the Ga-normalized PDH rates for all catalysts, albeit with a notably lower propene selectivity for (Ga,Al)2O3(1:6)/SiO2. Fourier transform infrared (FTIR) spectroscopy allows contrasting the H2 dissociation sites in the calcined and H2-treated (Ga,Al)2O3(x:y)/SiO2, indicating a transformation of Ga3+ surface sites with Al (mainly) and Ga atoms in the second coordination sphere (Ga(Al/Ga) sites) in the calcined (Ga,Al)2O3(1:6)/SiO2 to predominantly Ga(Ga/Si) surface sites in the H2-treated material. The resulting sites are similarly unselective as in amorphous gallia on silica. H2 produced during the PDH reaction can cause a similar transformation as H2 pretreatment in (Ga,Al)2O3(1:6)/SiO2, rapidly resulting in a notably lowered selectivity. The stable and selective Ga(Al/Ga) surface sites in (Ga,Al)2O3(1:3)/SiO2 yield a Ga−H band at ca. 1990 cm−1 under H2 dissociation conditions while the less selective surface sites, observed for the other Ga : Al ratios, give Ga−H bands at ca. 2040 and 2060 cm−1.","PeriodicalId":12842,"journal":{"name":"Helvetica Chimica Acta","volume":"107 8","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hlca.202400076","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142002523","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 6/2024) 封面图片： (Helv. Chim. Acta 6/2024)

IF 1.8 4区化学

Helvetica Chimica Acta Pub Date : 2024-06-14 DOI: 10.1002/hlca.202470601

引用次数: 0

Elastomers Based on Polynorbornene with Polar Polysiloxane Brushes for Soft Transducer Applications 基于聚降冰片烯的弹性体与极性聚硅氧烷刷，用于软传感器应用

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2024-06-10 DOI: 10.1002/hlca.202400032

Yeerlan Adeli, Thulasinath Raman Venkatesan, Frank A. Nüesch, Dorina M. Opris

{"title":"Elastomers Based on Polynorbornene with Polar Polysiloxane Brushes for Soft Transducer Applications","authors":"Yeerlan Adeli, Thulasinath Raman Venkatesan, Frank A. Nüesch, Dorina M. Opris","doi":"10.1002/hlca.202400032","DOIUrl":"10.1002/hlca.202400032","url":null,"abstract":"Elastomers based on cross-linked bottlebrush polymers combine an extreme softness at low strains with a strain-stiffening effect, which makes them attractive as active components in dielectric elastomer actuators (DEA). Their main disadvantage concerns the small relative permittivity, which is about 3.5, requiring relatively high driving voltage in actuators. We synthesized a bottlebrush polymer elastomer with polar brushes, which exhibit an enhanced dielectric permittivity of 4.4. Anionic ring-opening polymerization of a polar cyclosiloxane gave telechelic polar brushes, while ring-opening polymerization of a norbornene macromonomer gave a bottlebrush polymer which was cross-linked to elastomers by a thiol-ene reaction. Elastomers with a small elastic modulus below 100 kPa, strain at break exceeding 100 %, attractive elasticity, and small mechanical loss factors (tanδ) were achieved. Temperature-dependent impedance measurements revealed a transition temperature of −95 °C and an interfacial polarization. The multigram scale synthesis demonstrates the potential for scaling up, which opens the door to broader applications of these materials beyond actuators, such as capacitive sensors, batteries, and electroluminescent devices. Notably, these devices operate at extremely low voltages where the dielectric breakdown does not limit their functionality, but still, the softness and the increased dielectric permittivity are a plus.","PeriodicalId":12842,"journal":{"name":"Helvetica Chimica Acta","volume":"107 8","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hlca.202400032","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141363525","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

Nickel(II)-Catalyzed Hydrocarbamoylation of Alkynes with Formamides towards Unsaturated Amides 镍（II）催化的炔烃与甲酰胺的氢氨基化反应，生成不饱和酰胺

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2024-06-03 DOI: 10.1002/hlca.202400020

Tiangui Li, Shiyang Wang, Zongxiang Xia, Jinbo Zhao, Dongyue Zhang, Yuanqi Wu, Yu Liu

引用次数: 0