Synthesis of [3,4,8-C3]daidzein

The biological effects of the soy isoflavones have attracted considerable interest in recent years leading to numerous studies on dietary intake and epidemiology. Such studies require accurate and reproducible analytical methods. Herein we report the first synthesis of a multiply ¹³C-labelled daidzein derivative, [3,4,8-¹³C₃]daidzein, which has been employed as an internal standard in LC-MS and GC-MS analysis. The synthesis includes an improved three-step method for the synthesis of [2-¹³C]resorcinol as one building block.     

Predicting the Photoelectron Spectra of Quasi Octahedral Al6Mo- Cluster

We have recently developed a computational methodology to separate the effects of size, composition, symmetry and fluxionality in explaining the experimental photoelectron spectra of mixed-metal clusters. This methodology was successfully applied first in explaining the observed differences between the spectra of Al₁₃^- and Al₁₂Ni^- and more recently to explain the measured spectra of Al_nMo^-, n=3–5,7 clusters. The combination of our approach and new synthesis techniques can be used to prepare cluster-based materials with tunable properties. In this work we use the methodology to predict the spectrum of Al₆Mo^-. This system was chosen because its neutral counterpart is a perfect octahedron and it is distorted to a D_3d symmetry and was not observed in the recent experiments. This high symmetry cluster bridges the less symmetric Al₅Mo^- and Al₇Mo^-structures.The measured spectra of Al₅Mo^- has well defined peaks, while that of Al₇Mo^-does not. This can be explained by the fluxionality of Al₇Mo^-, as at least 6 different structures lie within the range that can be reached by thermal effects. We predict that Al₆Mo^- has well defined peaks, but some broadening is expected as there are two low-lying isomers, one of D_3d and the second of D_3h symmetry that are only 0.052 eV apart.     

The first stable examples of compounds containing both diazonium and acyl azide,and synthesis of a new pyrazino[2′,3′:3,4]pyrazolo[5,1-c][1,2,4]triazin-4(6H)-one heterocyclic system

The first stable compound containing both N₂⁺BF₄^? and CON₃ functional groups – 8-azidocarbonyl-3-(tert-butyl)-4-oxo-4,6-dihydropyrazolo[5,1-c][1,2,4]triazine-7-diazonium tetrafluoroborate was synthesized, and its stability and reactivity discussed. The Curtius rearrangement of 7-azido-3-(tert-butyl)-4-oxo-4,6-dihydropyrazolo[5,1-c][1,2,4]triazine-8-carbonylazide was investigated, and the synthesis of a novel heterocyclic system –pyrazino[2′,3′:3,4]pyrazolo[5,1-c][1,2,4]triazin-4(6H)-one is described.     

Synthesis of [1,2-3H2]-polystyrene

The synthesis of [1,2-³H₂]-polystyrene consisted of a two step reaction. First catalytic tritium gas addition to phenylacetylene was used to prepare [1,2-³H₂]-styrene and then it was polymerized to [1,2-³H₂]-polystyrene in the present of an initiator.     

A new reaction of P4S10 and Lawesson's reagent; a new method for the synthesis of dithieno[3,2-b;2,3-d]thiophenes

A new reaction of P₄S₁₀ and Lawesson's reagent for the synthesis of fused thiophenes has been uncovered. It has given easy access to the synthesis of derivatives of the technologically important heterocycle dithieno[3,2-b;2^′,3^′-d]thiophene, DTT. Electrochemical polymerization of one of the derivatives has been demonstrated.     

基于尿素电合成反应的电催化剂研究进展

尿素是一种重要的化工原料并作为氮源广泛应用于化肥生产。工业合成尿素由氮气加氢合成氨气以及氨气和二氧化碳转化为尿素两步实现,存在高能耗和高污染等问题。通过电催化碳氮偶联,将二氧化碳和氮源（氮气、硝酸根、亚硝酸根、一氧化氮等）转化为尿素,可直接跳过合成氨反应并在温和的反应条件下同时实现人工固氮和固碳。因此,尿素电合成技术不仅避免了高能耗和高污染,还能够实现惰性气体分子的高效利用,对于加快实现“碳达峰碳中和”战略有着重要的意义。本文聚焦尿素电合成这一前沿研究热点,结合领域内最新研究进展,首先介绍了不同电催化剂的设计策略及其催化机制,随后总结了电催化碳氮偶联合成尿素的反应机理,并对尿素电合成的后续研究方向进行了展望。     

软化学法合成有机杂化锗、锡硫属化物的研究进展

本文总结了软化学方法合成有机杂化的锗、锡硫属化合物的研究进展，介绍了代表性物质的结构以及[M₂Q₆]^4-、[M₃Q₇]2-、[M₄Q₉]^2-、[M₄Q₁₀]^4-(M=Ge，Sn；Q=S，Se，Te)等构筑单元的超分子组装、聚合过程中的主要影响因素。     

Practical synthesis of d-[1-C]mannose, l-[1-C] and l-[6-C]fucose

The chemical synthesis of ¹³C-labeled mannose and fucose is important for the preparation of molecular probes used in the conformational study of the oligosaccharide portions of glycoproteins. A new method for the synthesis of the title [1-¹³C]-labeled compounds via the corresponding olefin compounds, which are in turn derived from d-mannitol or l-arabinose by efficient introduction of ¹³C, by the Wittig reaction using Ph₃P¹³CH₃I and n-BuLi, is described. The introduction of ¹³CH₃I to produce the [1-¹³C]- and [6-¹³C]-labeled compounds was accomplished in 62%, 56%, and 71% yields, respectively. All mannose and fucose protons, from H-1 to H-6, were observed by the HMQC-TOCSY technique using 1:1 mixtures of [1-¹³C]- and [6-¹³C]-labeled compounds.     

Synthesis of [3-<Superscript>14</Superscript>C]-L-tryptophan and 5′-hydroxy-[3-<Superscript>14</Superscript>C]-L-tryptophan

The synthesis of selectively labeled [3-¹⁴C]-L-tryptophan and its derivative 5′-hydroxy-[3-¹⁴C]-L-tryptophan using chemical and multienzymatic methods is reported. The key intermediate for this synthesis, [3-¹⁴C]-DL-alanine was obtained from ¹⁴CH₃I as a result of its condensation with N-(diphenylmethylene)glycine tert-butyl ester. Next, the mixture containing [3-¹⁴C]-DL-alanine, indole or 5-hydroxyindole has been converted to [3-¹⁴C]-L-tryptophan or 5′-hydroxy-[3-¹⁴C]-L-tryptophan, respectively, in a one-pot multienzymatic reaction using four enzymes: D-amino acid oxidase, catalase, glutamic-pyruvic transaminase and tryptophanase.     

Mechanochemical Synthesis of Phosphates and Phase Transformations of Natural Apatites by Mechanical Action

Abstract

The mechanochemical method is a promising way of synthesizing new and complicate phosphorus compounds and processing phosphate rocks in order to obtain the fertilizers. Apatites with general compositional formula-Me₁₀(RO₄)₆Z₂, Ca²⁺, Ba²⁺, Cu²⁺, Pb²⁺, Mn²⁺, Fe²⁺, A1³⁺; RO₄ -PO^3- ₄, Co^2- ₃, Alo^? ₂, Sio^4- ₄, So^2- ₄, Zro^4- ₄; z-F^? F^?, OH^?, cl^?, CO^2- ₃, O^? S^2-, HCOO^? and isomorphous mixtures by mechanical action in planetary mill at room temperature were synthesized. Duration of the synthesis varied from 5 min. to 30 min. The initial components for synthesis were phosphates, oxides, chemical elements (Si, S, Al, Cu, Pb, Fe) and organic compounds. The synthetic apatites are promising materials for the production of bioceramic, catalysts, ion-exchangers and laser glasses.     

Synthese regioselective de bases de mannich de cetones dissymetriques

Methods for the regioselective synthesis of Mannich bases starting from unsymmetrical ketones are described. The Mannich base on the more substituted carbon is obtained by reaction with (CH₃)₂N⁺CH₂,CF₃CO₂^- in CF₃CO₂H and its isomer on the less substituted carbon with (iPr)₂N⁺CH₂,ClO₄^- in CH₃CN. In the first case, the orientation corresponds to a non-selective attack of the immonium salt on a mixture of enols in which the more-substituted isomer is predominant. In the second ease, use of a bulky immonium salt induces a selectivity favoring the less-substituted enol.     

Synthesis of [carbonyl-C]acetophenone via the Stille cross-coupling reaction of [1-C]acetyl chloride with tributylphenylstannane mediated by Pd2(dba)3/P(MeNCH2CH2)3N·HCl

The Stille cross-coupling reaction of [1-¹¹C]acetyl chloride with tributylphenylstannane leading to [carbonyl-¹¹C]acetophenone was studied with the goal of developing a new ¹¹C-labeling method for positron emission tomography tracer synthesis. The coupled product [carbonyl-¹¹C]acetophenone was synthesized using the Pd₂(dba)₃/P(MeNCH₂CH₂)₃N·HCl system with a 60-61% radiochemical conversion from [1-¹¹C]acetyl chloride (decay-corrected, n = 3).     

Pterin chemistry. Part 88. A simple synthesis of 5-Deoxy-L-[5-2H1]arabinose and L-[3′-2H1] biopterin

A simple synthesis of 5-deoxy-L -[5-²H₁]arabinose was performed to obtain L -[3′-²H₁]biopterin. The reduced form of this model substance is needed to investigate the pathway of 7-substituted pterins in patients with primapterinuria.     

Iron(III) catalyzed direct C–H functionalization at the C-3 position of chromone for the synthesis of fused chromeno-quinoline scaffolds

This communication describes an iron-catalyzed route for the synthesis of 6-substituted chromeno[3,2-c]quinolin-7-one. The method developed does not require any pre-functionalization to execute the pivotal coupling reaction at the C-3 position of flavones. The final step involves the consecutive application of imine formation, C_sp²-C_sp² coupling and oxidation reaction, with aromatic aldehydes and 2-(2-aminophenyl)-4H-chromen-4-one as the reactants. Presence of electron donating/withdrawing groups was well tolerated in the aldehydes and the method developed could also be extended to other substituted 2-(2-aminophenyl)-4H-chromen-4-one’s. This is the first report of synthesis of 6-substituted chromeno[3,2-c]quinolin-7-one’s via direct functionalization of the C-3 site of flavones.     

A highly efficient synthesis of [1-C, O]- and [1-C, H2]-glycerol for the elucidation of biosynthetic pathways

Labeled glycerol is a widely used biochemical probe to investigate biosynthetic pathways. A highly efficient synthesis of [1-¹³C, ¹⁸O]- and [1-¹³C, ²H₂]-glycerol is described in which the ¹³C label is introduced using cyanide. The ¹⁸O label was introduced by a Pinner synthesis and reduction of the ester 5 allowed incorporation of the ²H labels.     

Improved Synthesis of Phosphoramidite-Protected N6-Methyladenosine via BOP-Mediated SNAr Reaction

N⁶-methyladenosine(m⁶A) is the most abundant modification in mRNA. Studies on proteins that introduce and bind m⁶A require the efficient synthesis of oligonucleotides containing m⁶A. We report an improved five-step synthesis of the m⁶A phosphoramidite starting from inosine, utilising a 1-H-benzotriazol-1-yloxytris(dimethylamino)phosphoniumhexafluorophosphate (BOP)_-mediated S_NAr reaction in the key step. The route manifests a substantial increase in overall yield compared to reported routes, and is useful for the synthesis of phosphoramidites of other adenosine derivatives, such as ethanoadenosine, an RNA analogue of the DNA adduct formed by the important anticancer drug Carmustine.     

A Synthetic Strategy for Cofacial Porphyrin-Based Homo- and Heterobimetallic Complexes

We present a straightforward and generally applicable synthesis route for cofacially linked homo- and heterobimetallic porphyrin complexes. The protocol allows the synthesis of unsymmetrical aryl-based meso-meso as well as β-meso-linked porphyrins. Our method significantly increases the overall yield for the published compound known as o-phenylene-bisporphyrin (OBBP) by a factor of 6.8. Besides the synthesis of 16 novel homobimetallic complexes containing Mn^III, Fe^III, Ni^II, Cu^II, Zn^II, and Pd^II, we achieved the first single-crystal X-ray structure of an unsymmetrical cofacial benzene-linked porphyrin dimer containing both planar-chiral enantiomers of a Ni^II₂ complex. Additionally, this new methodology allows access to heterobimetallic complexes such as the Fe^III-Ni^II containing carbon monoxide dehydrogenase active site analogue. The isolated species were investigated by various techniques, including ion mobility spectrometry, DFT calculations, and UV/Vis spectroscopy. This allowed us to probe the influence of interplane distance on Soret band splitting.     

Higher Nuclearity Rhenium Halide Clusters That Contain Re–Re Multiple Bonds

The discovery that the rhenium chloride cluster Re₃Cl₉ and its chloro-anion [Re₃Cl₁₂]^3- contain a triangular cluster of Re atoms and Re–Re bond orders of two was first reported in 1963. This led very quickly to the report by F. A. Cotton of the first species with a metal–metal quadruple bond, namely, the [Re₂Cl₈]^2- anion. While the field of dinuclear multiple bond chemistry has undergone explosive growth in the last 40 years, that involving the chemistry of higher nuclearity clusters with metal–metal multiple bonds is much more limited. One of the relatively few exceptions is encountered with the aforementioned rhenium halides that contain the triangular [Re₃]⁹⁺ core. In the present review, the synthesis, structures and reactivity of these halide clusters and those of higher nuclearity that contain Re–Re multiple bonds are surveyed. This article provides a comprehensive review of the literature covering the 40 year period 1963–2003.     

Study of optimum condition for synthesis of [γ-32P]ATP with high specific radioactivity

The synthesis of [γ-³²P]ATP with high specific radioactivity was investigated by the enzymatic method. We utilized a part of the glycolytic pathway which consists of three reaction steps. First, we examined the maximum radioactivity of H₃ ³²PO₄ without the decrease of labeling yield. Next, we examined the minimum amount of reagent without the decrease of labeling yield, because some reagents contain the phosphorus species as impurity. In this paper, we propose the optimum condition for synthesis of [γ-³²P]ATP with high specific radioactivity. As our calculation, we will be able to obtain about 220 TBq/mmol specific radioactivity using 1.5 GBq of H₃ ³²PO₄.     

酰腙类化合物的合成和阴离子识别研究

本文设计合成了3种新型的酰腙类受体分子。利用紫外-可见吸收光谱及 ¹H NMR考察了其与F^-、Cl^-、Br^-、I^-、CH₃COO^-、HSO₄^-、NO₃^-等阴离子的作用。结果表明，该类受体分子能较好地识别阴离子F^-和CH₃COO^-，在DMSO溶液中主客体之间形成氢键加合物。尤其对于受体3(间苯双对硝基苯氧乙酰腙)，加入F^-和CH₃COO^-时，溶液颜色有明显变化，受体3对这两种阴离子可实现裸眼识别。