MgO Nanoparticles as a Recyclable Heterogeneous Catalyst for the Synthesis of Polyhydroquinoline Derivatives under Solvent Free Conditions

Magnesium oxide nanopartticels in average size between 35–120 nm were prepared by sonochemistry method. Synthesis of polyhydroquinoline derivatives using MgO nanoparticles from the reaction of dimedone, benzaldehyde, ethyl acetoacetate and ammonium acetate under solvent‐free conditions is reported. Easy handling, reusability, thermal stability and non‐toxicity of the catalyst make the present protocol as an eco‐friendly and economically acceptable method for synthesis of these heterocycles.     

Regioselective synthesis of polysubstituted 4H-thiopyrans from β-oxodithioesters

A simple and efficient method for the synthesis of polyfunctionalized 4H-thiopyrans by highly regioselective cyclocondensation of β-oxodithioesters with 1,1,3-trialkyl or aryl substituted prop-2-yn-1-ols using BF₃·Et₂O as the catalyst is described.     

In vivo molecular evaluation of guinea pig skin incisions healing after surgical suture and laser tissue welding using Raman spectroscopy

The healing process in guinea pig skin following surgical incisions was evaluated at the molecular level, in vivo, by the use of Raman spectroscopy. After the incisions were closed either by suturing or by laser tissue welding (LTW), differences in the respective Raman spectra were identified. The study determined that the ratio of the Raman peaks of the amide III (1247 cm⁻¹) band to a peak at 1326 cm⁻¹ (the superposition of elastin and keratin bands) can be used to evaluate the progression of wound healing. Conformational changes in the amide I band (1633–1682 cm⁻¹) and spectrum changes in the range of 1450–1520 cm⁻¹ were observed in LTW and sutured skin. The stages of the healing process of the guinea pig skin following LTW and suturing were evaluated by Raman spectroscopy, using histopathology as the gold standard. LTW skin demonstrated better healing than sutured skin, exhibiting minimal hyperkeratosis, minimal collagen deposition, near-normal surface contour, and minimal loss of dermal appendages. A wavelet decomposition–reconstruction baseline correction algorithm was employed to remove the fluorescence wing from the Raman spectra.     

以液体核磁共振波谱分析与帕金森氏病相关的I93M 突变对人类泛素碳端水解酶结构的影响

人类泛素碳端水解酶（UCH-L1）是涉及帕金森氏病并且在神经元高度表达的蛋白．UCH-L1 的家族性突变与转译后修饰会引起聚集倾向增加与去泛素活性损失,这二者都可能成为致病因素．作者所在实验室之前的研究指出与帕金森氏病相关的突变I93M 显著降低UCH-L1 的折叠稳定性并且加速其构型展开动力学．该研究使用液体核磁共振分析方法,包括侧链甲基化学位移,松弛骨干动力学和残余偶极耦合,以进一步阐明I93M 突变如何影响UCH-L1 的结构和动态．结果显示I93M 显著影响突变位点周围的疏水核心侧链构型．然而,这样的结构扰动并不会影响在纳秒时间尺度的快速骨干动力学．透过残余偶极耦合分析显示UCH-L1 在水溶液中的结构与之前报道的晶体结构有相当显著的偏离,另外I93M 突变也导致超出突变位点的远距离结构扰动．这一系列水溶液结构的分析结果可补充之前已知的晶体学数据,并对UCH-L1 在帕金森氏病相关的基因突变影响并提供详细的见解．     

New method for the preparation of N-chloroamines by oxidative N-halogenation of amines using oxone-KCl

A mild and efficient method for preparation of N-chloroamines by oxidative N-halogenation of primary/secondary amines using oxone-KCl is described.     

Efficient synthesis of N-allylated 2-nitroiminoimidazolidine analogues from Baylis–Hillman bromides

Various Baylis–Hillman–derived new N-allylated 2-nitroiminoimidazolidine analogs were efficiently prepared using potassium carbonate as base. Simple workup procedure, excellent yields, and mild reaction conditions are the salient features of this method. All the synthesized compounds are screened for their larvicidal activity on fourth instar mosquito larvae, Culex quinquefasciatus.     

Self‐Assembly of Bare/Polymer‐Grafted Nanoparticle Blends in Homopolymer

The self‐assembly of a binary blend of nanoparticles in a homopolymer matrix using molecular dynamics (MD) simulations is studied here. The systems consist of polymer matrix, “bare” ungrafted spherical nanoparticles and polymer‐grafted nanoparticles, where the particle cores are identical and grafted chains are similar to matrix polymer. It is observed that addition of grafted nanoparticles to a blend of polymer and bare particles can result in the formation of anisotropic structures. By carefully selecting the graft density and molecular weight of the grafted chains, the clusters go from spherical to cylindrical to branched cylinders. This study suggests that it is indeed possible to control the morphology of bare nanoparticles in polymer without directly modifying their surface properties. It is believed that this phenomenon might be of high importance, especially in cases such as polymer‐based solar cells, where it is not feasible to graft the nanoparticles with polymer chains to achieve a greater level of control over the morphology.

     

Efficient multicomponent synthesis of spiro[indoline-3,4′-thiopyran]-2-ones

Synthesis of new thiopyran fused spirooxindoles (spiro[indoline-3,4′-thiopyran]-2-ones) were achieved by a multicomponent reaction of N-methyl isatin, malononitrile/ethyl cyanoacetate, and β-oxodithioester using N,N′-dimethylaminopyridine as the catalyst.     

Synthesis and biological assessment of some fused Pyran derivatives

Pyran was formed by reacting methyl 3-methoxyacrylate (1) with 2-benzylidenemalanonitrile to form compound 2 . The pyrano derivatives 3–6 were obtained by reacting the second molecule with 2-benzylidenemalanonitrile, carbon disulfide, formamide, and benzylidene cyclohexanone. Compound (2) interacted with ethyl chloroacetate to form compound 8 , which then cyclized in the presence of sodium ethoxide to form compound 9 . Compound 7 was formed when compound (2) was treated with acetic acid in the presence of sulfuric acid and reacted with ethylchloroacetate to form compound 10 and then was converted to compound 11 by the addition of sodium ethoxide. Analytical and spectral data have been used to determine the structures of the newly synthesized substances and they were then tested for their antibacterial and antioxidant activities. In terms of antioxidant activity, compounds 2 and 8 were found to have the greatest and lowest levels, respectively, against Enterobacter aerogenes.