The first oxalamide‐bridged ferrocene: Facile synthesis,preliminary conformational analysis and biological evaluation

tert ‐Butyl‐1′‐methoxycarbonyl‐1‐ferrocenecarbamate ( 1 ) was Boc‐deprotected to give free amine which underwent oxalyl chloride‐mediated dimerization. The structure of the so‐obtained oxalamide‐bridged ferrocene 2 was elucidated using infrared and NMR (¹H, ¹³C, COSY, NOESY, HSQC, HMBC) spectroscopies, crystal structure analysis, and electrospray ionization and high‐resolution mass spectrometry. The preliminary conformational analysis in solution suggested the intramolecular engagement of oxalamide protons, while single‐crystal analysis revealed an intermolecular hydrogen‐bonding pattern. Also, the effect of oxalamide‐bridged ferrocene 2 on cell viability of three human cell lines (HEK293T, HeLa and HepG2) was tested. In vitro screening revealed proliferative as well as cytotoxic effects of the tested compound in the applied concentration range (1–350 μM) on HEK293T and HepG2 cells. Stimulatory effect on cell growth was the most pronounced for normal HEK293T cells, while the highest cytotoxic effect was observed towards HeLa tumour cells and it was dose‐dependent. The observed dual biological activity of 2 implies its potential application in drug development.     

Chiral Hexa‐ and Nonamethylene‐Bridged Bis(L‐Leu‐oxalamide) Gelators: The First Oxalamide Gels Containing Aggregates with a Chiral Morphology

Chiral amino acid‐ and amino alcohol‐oxalamides are well‐known as versatile and efficient gelators of various lipophilic and polar organic solvents and water. To further explore the capacity of the amino acid/oxalamide structural fragment as a gelation‐generating motif, the dioxalamide dimethyl esters 1₆Me and 1₉Me , and dicarboxylic acid 2₆OH / 2₉OH derivatives containing flexible methylene bridges with odd ( 9 ; n=7) and even ( 6 ; n=4) numbers of methylene groups were prepared. Their self‐assembly motifs and gelation properties were studied by using a number of methods (FTIR, ¹H NMR spectroscopy, CD, TEM, DSC, XRPD, molecular modeling, MMFF94, and DFT). In contrast to the previously studied chiral bis(amino acid or amino alcohol) oxalamide gelators, in which no chiral morphology was ever observed in the gels, the conformationally more flexible 1₆Me , 1₉Me , 2₆OH , and 2₉OH provide gelators that are capable of forming diverse aggregates of achiral and chiral morphologies, such as helical fibers, twisted tapes, nanotubules, straight fibers, and tapes, in some cases coexisting in the same gel sample. It is shown that the differential scanning calorimetry (DSC)‐determined gelation enthalpies could not be correlated with gelator and solvent clogP values. Spectroscopic results show that intermolecular hydrogen‐bonding between the oxalamide units provides the major and self‐assembly directing intermolecular interaction in the aggregates. Molecular modeling studies reveal that molecular flexibility of gelators due to the presence of the polymethylene bridges gives three conformations ( zz , p1 , and p2 ) close in energy, which could form oxalamide hydrogen‐bonded layers. The aggregates of the p1 and p2 conformations tend to twist due to steric repulsion between neighboring iBu groups at chiral centers. The X‐ray powder diffraction (XRPD) results of 1₆Me and 1₉Me xerogels prove the formation of p1 and p2 gel aggregates, respectively. The latter results explain the formation of gel aggregates with chiral morphology and also the simultaneous presence of aggregates of diverse morphology in the same gel system.     

Syntheses and characterization of the vanadium trimer (V3(μ3-O)O2)(μ2-O2P(CH2C6H5)2)6(4,4′-bipyridine) and the vanadium hexamer [(V3(μ3-O)O2)(μ2-O2P(CH2C6H5)2)6]2(μ2-N1,N2-di(pyridin-4-yl)oxalamide)

Reacting VO(acac)₂ with six equivalents of dibenzylphosphinic acid in the presence of 4,4′-bipyridine or μ₂-N¹,N²-di(pyridin-4-yl)oxalamide leads to trimeric (V₃(μ₃-O)O₂)(μ₂-O₂P(CH₂C₆H₅)₂)₆(4,4′-bipyridine) or the hexamer [(V₃(μ₃-O)O₂)(μ₂-O₂P(CH₂C₆H₅)₂)₆]₂(μ₂-N¹,N²-di(pyridin-4-yl)oxalamide). The complexes were characterized by spectroscopic (FTIR and ¹H NMR spectroscopies), TGA, and by single crystal X-ray diffraction measurements. The structures consist of a planar central core where three vanadium ions are arranged in the form of a quasi-isosceles triangle and contain an interstitial O which is multiply bonded to one V and weakly interacting at different bond distances to the remaining two V ions.     

草酰胺桥联大环二羰四胺Cu(Ⅱ)-M(Ⅱ)(M=Mn,Ni,Cu,Zn)异双核配合物的合成与表征

合成了四种新型具有草酰胺桥联大环二羰四胺结构Cu(Ⅱ ) -M(Ⅱ ) (M =Mn ,Ni,Cu ,Zn)的双核配合物 ,并用元素分析 ,红外光谱 ,紫外光谱 ,摩尔电导 ,热重分析 ,室温磁矩等手段对其进行了结构表征 .经研究推定 ,此配合物具有草酰胺桥联结构 ,Cu(Ⅱ )处于平面正方场M(Ⅱ )处于八面体场中 .室温磁矩测定表明通过草酰胺桥联配体金属离子间有一定的反铁磁性自旋偶合相互作用     

Two cobalt(II) supramolecular isomers based on N,N′‐bis(pyridin‐3‐yl)oxalamide induced by the molecular orientation of lattice DMF molecules

Supramolecular isomerism for coordination networks refers to the existence of different architectures having the same building blocks and identical stoichiometries. For a given building block, different arrangements can lead to the formation of a series of supramolecular isomers. Two one‐dimensional Co^II coordination polymers based on N,N′‐bis(pyridin‐3‐yl)oxalamide (BPO), both catena‐poly[[[dichloridocobalt(II)]‐bis[μ‐N,N′‐bis(pyridin‐3‐yl)oxalamide‐κ²N:N′]] dimethylformamide disolvate], {[CoCl₂(C₁₂H₁₀N₄O₂)₂]·2C₃H₇NO}_n, have been assembled by the solvothermal method. Single‐crystal X‐ray diffraction analyses reveal that the two compounds are supramolecular isomers, the isomerism being induced by the orientation of the dimethylformamide (DMF) molecules in the crystal lattice.     

A new fluorescent probe of rhodamine B derivative for the detection of copper ion

A new fluorescent probe, rhodamine B hydrazide oxalamide (RBHO), which shows very weak fluorescence, was synthesized, and its fluorescence could be substantially enhanced by the addition of copper ion. The probe shows a high selectivity and sensitivity to copper ion by forming a 1:1 complex in acetonitrile, and the chelating is reversible. Limit of detection for copper ion in acetonitrile was found to be 3.7 × 10⁻⁸ mol L⁻¹. It was also found that copper ion could catalyze the hydrolysis of the probe in 50% (v/v) buffered (10 mM Tris–HCl, pH 7.0) water/acetonitrile giving a highly fluorescent product, and the fluorescence detection of copper ion was developed in this neutral buffered media with a detection limit of 6.4 × 10⁻⁷ mol L⁻¹. Determination of copper ion in water and synthetic samples in the presence of different interfering metal ions was successfully carried out with the new probe RBHO.     

含嘧啶环乙二酰胺类化合物的合成及其对小菜蛾酪氨酸酶的抑制作用

酪氨酸酶在昆虫体内起着很重要的生理作用,控制酪氨酸酶的活性即可调节昆虫的生长行为,借鉴曲酸和铜铁试剂的杂原子螯合机理,设计了一类含嘧啶环乙二酰胺的新型化合物,以取代苯胺为起始原料经3步反应合成了目标化合物,其结构通过红外、核磁氢谱、质谱、高分辨质谱表征.生物活性测试表明该系列化合物对小菜蛾酪氨酸酶活性有一定的抑制作用.     

Visible-Light-Induced Palladium-Catalyzed Dehydrogenative Carbonylation of Amines to Oxalamides

The palladium-catalyzed oxidative carbonylation of amines toward the synthesis of oxalamides has been established around 30 years ago and it usually needs the presence of (over)stoichiometric amounts of oxidant. In this work, the first transformation of this type in which the oxidant was replaced by visible light is described. The new approach uses a simple robust Pd complex, which can even be partially recycled. A mechanistic reason is provided and supported by control experiments and EPR studies, showing that Pd^I was formed and Pd⁰ was the active species. Both nitrogen- and the intermediate acyl radical can be detected. Moreover, the formation of hydrogen was confirmed by gas GC.