COVID-19 and One-Carbon Metabolism

Dysregulation of one-carbon metabolism affects a wide range of biological processes and is associated with a number of diseases, including cardiovascular disease, dementia, neural tube defects, and cancer. Accumulating evidence suggests that one-carbon metabolism plays an important role in COVID-19. The symptoms of long COVID-19 are similar to those presented by subjects suffering from vitamin B₁₂ deficiency (pernicious anemia). The metabolism of a cell infected by the SARS-CoV-2 virus is reshaped to fulfill the need for massive viral RNA synthesis, which requires de novo purine biosynthesis involving folate and one-carbon metabolism. Many aspects of host sulfur amino acid metabolism, particularly glutathione metabolism underlying antioxidant defenses, are also taken over by the SARS-CoV-2 virus. The purpose of this review is to summarize recent findings related to one-carbon metabolism and sulfur metabolites in COVID-19 and discuss how they inform strategies to combat the disease.     

Advantage of Dimethyl Sulfoxide in the Fabrication of Binder-Free Layered Double Hydroxides Electrodes: Impacts of Physical Parameters on the Crystalline Domain and Electrochemical Performance

The electrode fabrication stage is a crucial step in the design of supercapacitors. The latter involves the binder generally for adhesive purposes. The binder is electrochemically dormant and has weak interactions, leading to isolating the active material and conductive additive and then compromising the electrochemical performance. Designing binder-free electrodes is a practical way to improve the electrochemical performance of supercapacitors. However, most of the methods developed for the fabrication of binder-free LDH electrodes do not accommodate LDH materials prepared via the co-precipitation or ions exchange routes. Herein, we developed a novel method to fabricate binder-free LDH electrodes which accommodates LDH materials from other synthesis routes. The induced impacts of various physical parameters such as the temperature and time applied during the fabrication process on the crystalline domain and electrochemical performances of all the binder-free LDH electrodes were studied. The electrochemical analysis showed that the electrode prepared at 200 °C-1 h exhibited the best electrochemical performance compared to its counterparts. A specific capacitance of 3050.95 Fg⁻¹ at 10 mVs⁻¹ was achieved by it, while its Rct value was 0.68 Ω. Moreover, it retained 97% of capacitance after 5000 cycles at 120 mVs⁻¹. The XRD and FTIR studies demonstrated that its excellent electrochemical performance was due to its crystalline domain which had held an important amount of water than other electrodes. The as-developed method proved to be reliable and advantageous due to its simplicity and cost-effectiveness.     

Increased Sulfur Precursors and Volatiles Production by the Leek <Emphasis Type="Italic">Allium porrum</Emphasis> in Response to Specialist Insect Attack

To defend themselves against herbivory, plants use a variety of direct and indirect strategies involving induced increases in secondary substances. Species of the Allium genus (Alliaceae), such as the leek Allium porrum (L.), produce nonprotein sulfur amino acids derived from cysteine, i.e., alk(en)yl-cysteine sulfoxides that are precursors of volatile thiosulfinates and disulfides. These defend most species including the specialist leek moth, Acrolepiopsis assectella. We determined by measuring the increase in the sulfur precursor propyl-cysteine sulfoxide (PCSO) if production of this precursor is induced in response to moth attack and mechanical wounding. The concentration of PCSO was determined by HPLC in 2- or 6-mo-old leeks after attacks of various intensity either by the specialist leek moth or by a generalist moth, Agrotis ipsilon. Injury-induced release of sulfur volatiles was measured by GC/MS after the attacks. Results showed an increase in the production of sulfur compounds in both the precursor and volatile form, occurring only in association with intensive attacks by leek moths. The increase in sulfur precursors also led to an increase in the release of sulfur volatiles. This induced response may provide an effective defense strategy against the plant’s main natural enemy, both directly and indirectly by attracting entomophagous insects.     

二正辛基亚砜萃取钯(Ⅱ)的动力学和机理

用两相充分混合法研究了二正辛基亚砜(DOSO)从盐酸介质中萃取Pd(11)的动力学及机理,考察了水相[H~+]、[Cl~-]、有机相[DOSO]及温度对萃取的影响,测定了饱和萃合物的组成、红外光谱及电子光谱,借助数模在电子计算机上模拟萃取过程,建立了相应的动力学方程。结果表明:当正HCl]<2N时,Pd(Ⅱ)以配位机理被萃,萃取率受[H~+]影响很小,但随[Cl~-]增加而降低,过程吸热,饱和萃合物为trans-[Pd(DOSO)_2Cl_2];当[HCl]>2N后,Pd(Ⅱ)以(?)盐—DOSO配位两步机理被萃,萃取率受[Cl~-]影响很小,但随[H~+]增加而升高,过程放热,饱和萃合物为trans—[Pd(DOSO)_2Cl_2]·[H(H_2O)(DOSO)]·Cl。研究结果解释了Pd(Ⅱ)萃取率—[HCl]曲线中在2NHCl附近出现“凹谷”的原因。     

凝固浴浓度在线控制在PAN原丝生产中的应用

介绍了一种用于PAN原丝工业化生产装置的智能控制系统及其工作原理。通过在线监测凝固浴浓度(DMSO溶液),自动调节补水量,以维持凝固浴浓度的稳定。该装置的使用可提高工艺参数的控制精度,在腈纶湿法纺丝及PAN基碳纤维原丝工业化生产中具有广阔的应用前景。     

二茂铁合成新方法的研究

以环戊二烯 (CPD)、氯化亚铁 (FeCl2 ·4H2 O)、氢氧化钠 (NaOH)为原料 ,以二甲基亚砜为溶剂合成了二茂铁 ,n(CPD)∶n(NaOH)∶n(FeCl2 ·4H2 O) =1∶2∶0 5 ,产率为 93%。     

Potassium Hydroxide/Dimethyl Sulfoxide Superbase‐Promoted Transition Metal‐Free Synthesis of 2‐Substituted Benzothiophenes under Visible Light

A potassium hydroxide/dimethyl sulfoxide (KOH/DMSO) superbase‐promoted method for the synthesis of 2‐substituted benzothiophenes has been developed via photoinduced intermolecular annulation of 2‐halothioanisoles with terminal alkynes at ambient temperature. The present protocol uses commercially available 2‐halothioanisoles as substrates and visible light as energy force, which offers a wide range of benzothiophenes regioselectively in moderate to good yields. Such a facile and effective transformation will provide an environment‐friendly approach to the synthesis of benzothiophene derivatives.

     

The reaction of alkynes with dimethyl sulfoxide,halogenated hydrocarbons and sulfur trioxide

1,2-Disubstituted alkynes are converted in CCl₄ or CHCl₃ with dimethyl sulfoxide in the presence of sulfur trioxide into the corresponding (E, Z)-1-chloro-2-methylthio-ethenes. The reaction of 1,2-diphenylethyne with CHBr₃, DMSO, and dioxane sulfotrioxide gives (E, Z)-1,2-dimethylthio-1,2-diphenylethene.     

亚砜配体在金属催化烯丙基官能团化反应中的应用

过渡金属催化的烯丙基官能团化反应在有机合成中具有重要作用,是构建碳碳键和碳杂原子键的重要方法。亚砜配体以其独特的立体化学性质,不仅在传统的（Tsuji-Trost）烯丙基取代反应中取得优异结果,而且在烯丙基碳氢活化反应中展现出巨大潜力。本文根据产生烯丙基钯中间体的催化反应机理及亚砜配体配位模式的不同,总结了近些年亚砜配体在传统的烯丙基取代、烯丙基碳氢官能团化及不对称烯丙基碳氢官能团化领域的最新研究进展,指出影响各个催化体系的关键因素及所存的问题并对今后发展做出了展望。