Aqueous-Phase Synthesis of 2-Aminothiazole and 2-Iminothiazolidine Derivatives catalyzed by Diammonium Hydrogen Phosphate and DABCO

2-Aminothiazole and 2-iminothiazolidine derivatives were synthesized from the reaction of phenacyl bromide, thiourea, and its derivatives in aqueous media catalyzed by diammonium hydrogen phosphate (10%) and DABCO (10%) at room temperature in an efficient and simple procedure.     

Synthesis of Thiourea‐Bridged Cluster Glycoside Calixarenes

Thiourea‐bridged peracetylated glycoside calixarenes have been smoothly synthesized by the addition reactions of tetraacetylglycosyl isothiocyanates with amidoamine derivatives of calix[4]resorcinarene and p‐tert‐butylcalix[n]arenas (n=6, 8) in high yields (40–75%). All the glycoside‐containing calixarenes were characterized by ¹H NMR, IR spectroscopy, and elemental analysis.     

Weak and strong hydrogen bonds conducting the supramolecular framework of 1-butyl-3-(1-naphthoyl)thiourea: crystal structure,vibrational studies,DFT methods,Pixel energies and Hirshfeld surface analysis

A detailed structural and spectroscopic study of a new thiourea derivative 1-butyl-3-(1-naphthoyl)thiourea (1) is presented with the assistance of theoretical calculations. The X-ray diffraction structure analysis reveals a planar carbonylthiourea group, favoured by intra-molecular NH···O bond. The compound is arranged in the lattice as NH···O and NH···S bonded polymeric ribbons, that extend along the crystal b-axis. Molecular pairs involving N–H···S hydrogen bonds are a dominant contribution to packing stabilisation coming from coulombic component. Hirshfeld surfaces and two-dimensional-fingerprint plots show different intermolecular contacts and its relative contributions to total surface in each compound. The AIM approach shows the nature and strength of the strong and weak intramolecular interactions and the solvent effect, while NBO analysis reveals that the sulphur atom is responsible for the higher hyperconjugative stabilising energy.     

岩矿样品金元素分析中硫脲解脱流程的改进

硫脲解脱流程作为金矿样品金分析测试重要的前处理环节,在采用传统的水浴锅解脱流程测试过程中,发现存在耗电量大、比色管易进水汽、易结垢、架易腐蚀掉落等缺点。为了改善上述问题,本实验室在金分析过程中对解脱流程尝试做了改进,更换常用的水浴锅为恒温烘箱进行解脱,进而做了对比。同时,本研究对烘箱参数、温度设置、加热时间等做了对比分析,以获得最佳处理物理环境,并对改进前后所获得的测试结果进行了相关性分析,以判别其测试结果的可替代性。结果表明：采用烘箱代替水浴锅解脱,具有升温快,温度可控,耗电低,效率高,安全卫生,质量稳定可靠等优势。烘箱参数推荐设置为P:28、I:200、D:50,烘箱解脱过程中温度应控制95-102℃之间,升温时间15 min之后解脱液即可达到90 ℃以上,解脱时间一般需要35-40 min。通过相关性分析,其相关性系数均在0.99以上,呈近函数高度相关关系,由此认为,在实验室金分析过程中,烘箱代替水浴锅解脱完全可行,烘箱解脱更具有优势,应推广应用。     

Bis-Amiridines as Acetylcholinesterase and Butyrylcholinesterase Inhibitors: N-Functionalization Determines the Multitarget Anti-Alzheimer’s Activity Profile

Using two ways of functionalizing amiridine—acylation with chloroacetic acid chloride and reaction with thiophosgene—we have synthesized new homobivalent bis-amiridines joined by two different spacers—bis-N-acyl-alkylene (3) and bis-N-thiourea-alkylene (5) —as potential multifunctional agents for the treatment of Alzheimer’s disease (AD). All compounds exhibited high inhibitory activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) with selectivity for BChE. These new agents displayed negligible carboxylesterase inhibition, suggesting a probable lack of untoward drug–drug interactions arising from hydrolytic biotransformation. Compounds 3 with bis-N-acyl-alkylene spacers were more potent inhibitors of both cholinesterases compared to compounds 5 and the parent amiridine. The lead compounds 3a–c exhibited an IC₅₀(AChE) = 2.9–1.4 µM, IC₅₀(BChE) = 0.13–0.067 µM, and 14–18% propidium displacement at 20 μM. Kinetic studies of compounds 3a and 5d indicated mixed-type reversible inhibition. Molecular docking revealed favorable poses in both catalytic and peripheral AChE sites. Propidium displacement from the peripheral site by the hybrids suggests their potential to hinder AChE-assisted Aβ₄₂ aggregation. Conjugates 3 had no effect on Aβ₄₂ self-aggregation, whereas compounds 5c–e (m = 4, 5, 6) showed mild (13–17%) inhibition. The greatest difference between conjugates 3 and 5 was their antioxidant activity. Bis-amiridines 3 with N-acylalkylene spacers were nearly inactive in ABTS and FRAP tests, whereas compounds 5 with thiourea in the spacers demonstrated high antioxidant activity, especially in the ABTS test (TEAC = 1.2–2.1), in agreement with their significantly lower HOMO-LUMO gap values. Calculated ADMET parameters for all conjugates predicted favorable blood–brain barrier permeability and intestinal absorption, as well as a low propensity for cardiac toxicity. Thus, it was possible to obtain amiridine derivatives whose potencies against AChE and BChE equaled (5) or exceeded (3) that of the parent compound, amiridine. Overall, based on their expanded and balanced pharmacological profiles, conjugates 5c–e appear promising for future optimization and development as multitarget anti-AD agents.     

高效细内径毛细管电色谱填充柱的制备

发展了一套毛细管填充柱制备方法,在１００μｍ内径毛细管柱中填充３μｍＯＤＳ固定相,以毛细管电色谱法（ＣＥＣ）分离模式对芳香胺类样品进行分离,柱效高达２５．９万理论塔板数／米,折合塔板高度达１．３。类似研究在国内尚未见报道。     

Growth kinetics of zinc(tris)thiourea sulphate (ZTS) crystals

Growth kinetics of zinc (tris) thiourea sulphate (ZTS) crystals investigated as a function of supersaturation is reported in this communication. Crystal growth rates were investigated normal to the (100), (010) and (001) faces under growth conditions employed for bulk crystal growth. The growth rates normal to (010) and (100) were found to follow the continuous growth model (R_G = Cσ) with respect to the supersaturation whereas the growth rates normal to (001) was found to satisfy birth and spread (B+S) model (R_G = Aσ^5/6 exp(‐B/σ)). The growth rates observed normal to the studied face are in agreement with the growth mechanism predicted from the estimated α (Jackson) factor. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

水热法合成MOS2层状材料及其结构表征

以硫脲为还原剂和硫源,利用水热法在160～220℃下反应,合成了具有很好晶相的MoS2．采用XRD,XPS和TEM对其进行了结构表征,比较了反应温度对于成晶的影响,并且讨论了反应机理．研究表明,用此种方法合成MoS2较以往的水热合成所用时间短,温度低,获得的晶相好,同时还有效地避免了使用吡啶等有机溶剂所带来的污染,为合成其他过渡金属硫化物提供了新途径．     

[ReIII(thiourea-S)6]Cl3 · 4 H2O and [ReIII(N-methylthiourea-S)6]Cl3 as Precursors to other ReIII Complexes: a Kinetic Study in Aqueous Media. Crystal Structure of [ReIII(N-methylthiourea-S)6](PF6)3 · H2O

Capability of [Re^III(tu-S)₆]Cl₃, where tu = thiourea, as a precursor to other Re^III complexes by ligand substitution in aqueous medium is studied. For the decomposition of [Re(tu-S)₆]Cl₃, experiments suggest pseudo first order kinetics and observed rate constants vary from 1.3 × 10^–2 to 9.6 × 10^–2 min^–1 in the pH range 2.80–5.04. Experiments in presence of incoming ligand (ethylendiaminetetraacetic acid or diethylentriaminepentaacetic acid) show that ligand substitution is significantly slower than decomposition of the precursor, even when pH and temperature are modified. Similar results were obtained working with [Re^III(Metu-S)₆]Cl₃, where Metu = N-methylthiourea. Molecular structure of [Re^III(Metu-S)₆](PF₆)₃ · H₂O was determined by single crystal X-ray diffractometry. The coordination polyhedron around the Re ion is a distorted octahedron. The six methylthiourea ligands are bonded to the metal through the sulfur atoms [bond lengths range from 2.409(2) to 2.451(2) Å].     

Polymer-analogous transformations of poly(N-vinylpyrrolidone) to produce new complexing macromolecular systems

A new polymer-analogous transformations of poly(N-vinylpyrrolidone) was used to prepare new complex-forming macromolecular systems containing thiourea and thio-semicarbazone sites. Two variants of modification were realized, namely, the method including the preliminary in situ activation of nucleophilic centres of the polymer amide fragments with dimethyl sulfate followed by introducing nucleophilic agents into the system, and the method including partial hydrolysis of poly(N-vinylpyrrolidone) followed by the amide coupling. The obtained modified polymeric materials react with silver ions in aqueous solution.