Benzyl Ethers as Nucleophiles: From Hydroxy Cyclooctanes Toward Bridged C-Furanosides

Attempted Lewis acid-mediated opening of a benzyloxy-functionalized eight-membered ring epoxide resulted in an intramolecular nucleophilic attack by a favorably disposed benzyloxy group to give a bridged furanose. A corresponding intramolecular nucleophilic attack of a benzyloxy group in a triflated cyclooctenol again gave a bridged furanose derivative.     

Synthesis of novel bridged dinitrogen heterocycles and their evaluation as potential fragments for the design of biologically active compounds

A library of saturated bridged heterocycles based on 3,6-diazabicyclo[3.2.1]octane-2,4-dione and bispidine scaffolds (mean compound molecular weight is approximately 300 Da) with up to three stereocenters and four diversity points has been synthesized. Synthetic scaffold modifications leading to an increase in molecular complexity were studied. Well-defined stereochemical structures of both compound sets was confirmed by X-ray studies and halogenoaryl substituents were inserted appropriately for the design of novel non-basic serine protease inhibitors. Comprehensive molecular modeling has been performed for all synthesized compounds giving rationales of ligand–enzyme interactions with thrombin and trypsin. Biological testing confirmed moderate inhibitory activity of halogen-substituted saturated diazabicyclic small molecules towards thrombin.     

双金属层状配位聚合物{[ML][Fe~IIFe~III(ox)_3]·H_2O}_∞的合成和波谱表征

合成和表征了两种新的Schiff碱配合物 [ZnL(ClO4)·4H2 O (A)和CdL(ClO4)·3H2 O (B) ],其中L =2 { [2 (Aminomethyl amino) ethylimino] methyl} phenol.A(或B)、FeSO4·7H2 O和K3 [Fe(ox) 3 ]·3H2 O进一步反应 ,生成了配位聚合物 { [ML][FeIIFeIII(ox) 3 ]·H2 O} ∞ ,其中M =Zn2 + (C)或Cd2 + (D) .红外光谱和M ssbauer谱测定结果表明 ,C和D具有二维层状结构 ,其阴离子层由 [FeIIFeIII(ox) 3 ]-单元构成 .     

Ordered Hybrids from Template‐Free Organosilane Self‐Assembly

Despite considerable achievements over the last two decades, nonporous organic–inorganic hybrid materials are mostly amorphous, especially in the absence of solvothermal processes. The organosilane self‐assembly approach is one of the few opportunities for creating a regular assembly of organic and inorganic moieties. Additionally, well‐established organosilicon chemistry enables the introduction of numerous organic functionalities. The synthesis of periodically ordered hybrids relies on mono‐, bis‐, or multisilylated organosilane building blocks self‐assembling into hybrid mesostructures or superstructures, subsequently cross‐linked by siloxane Si‐O‐Si condensation. The general synthesis procedure is template‐free and one‐step. However, three concurrent processes underlie the generation of self‐organized hybrid networks: thermodynamics of amphiphilic aggregation, dynamic self‐assembly, and kinetically controlled sol–gel chemistry. Hence, the set of experimental conditions and the precursor structure are of paramount importance in achieving long‐range order. Since the first developments in the mid‐1990s, the subject has seen considerable progress leading to many innovative advanced nanomaterials providing promising applications in membranes, pollutant remediation, catalysis, conductive coatings, and optoelectronics. This work reviews, comprehensively, the primary evolution of this expanding field of research.     

Sacrificial BSA to block non‐specific adsorption on organosilane adlayers in ultra‐high frequency acoustic wave sensing

This follow‐up study describes the implementation of recently developed cross‐linking trichlorosilane surface chemistry with acoustic wave sensing technology for the real‐time and label‐free detection of biotin/avidin interactions. Biosensing platforms consist of unelectroded piezoelectric quartz resonator discs onto which functionalizable mixed organosilane adlayers are prepared using a new trichlorosilane cross‐linker in combination with a shorter monofunctional diluent molecule. Thiolated or aminated biotin probes can next be anchored to the mixed assembly in a single, preactivation‐free step through site‐specific coupling at pentafluorophenyl ester head moieties. Biosensing properties are assessed at ultra‐high frequency (>0.74 GHz) with the highly sensitive electromagnetic piezoelectric acoustic sensor using micromolar buffered solutions of avidin. This biosensor prototype – which generally displays good reproducibility – uses sacrificial bovine serum albumin to block non‐specific adsorption. This preliminary work in buffer constitutes an important step towards the development of real‐world biosensors able to perform with more demanding biological samples. Copyright © 2013 John Wiley & Sons, Ltd.     

A Pd-mediated intramolecular ketalization of alkynediols: construction of the central [3.2.1]-bicyclic ketal core of cyclodidemniserinol trisulfate

A preliminary study dealing with the Pd-mediated alkynediol cycloisomerization to construct the central bicyclic ketal core of cyclodidemniserinol trisulfate is documented.     

Synthesis and use of mono- or bisxylyl linked bis(benzimidazolium) bromides as carbene precursors for C-C bond formation reactions

Two benzimidazolium moieties linked by one or two xylyls (m- and p-) have been synthesized, characterized and then they were used for Heck coupling reactions as in situ formed catalysts. Mono bridged salts are more efficient as compared to bisbridged salts. In addition, mono bridged salts were converted to Rh-NHC complexes which were tested as catalysts for the arylation of aldehydes.     

Synthesis and characterization of some novel silicon esters and their application as lubricant base stock solution

A series of functional organosilanes and their esters were synthesized by the hydrosilylation reaction of Si? H group‐bearing organosilicon derivatives with maleic anhydride using Speier's catalyst and their esterification with long‐chain alcohols in the presence of stannous oxide. These products have been characterized using elemental analysis, FT‐IR, ¹H, ¹³C and ²⁹Si NMR. Viscosity, density, pour point, flash point and tribological properties of these compounds have also been evaluated. These esters have a pour point of 相似文献   

2,6,9-Trioxabicyclo[3.3.1]nona-3,7-dien-4-oyl and tetraoxaadamantan-9-oyl functionalized aromatic di- and triamines: synthesis, stereochemistry and complexation

Primary amino groups of di- or triaminoaryl compounds add a remarkably stable dioxinyl-α-oxoketene affording bis- or tris-[trioxabicyclo[3.3.1]nona-3,7-dienyl (bridged bisdioxine)] systems which can be converted into the corresponding bis- or tris-[2,4,6,8-tetraoxadamantanes] by acidic hydrolysis. Stereochemical peculiarities as well as preliminary host-guest abilities of these molecules are investigated with aid of NMR-spectroscopy, an X-ray analysis and ESI-mass spectrometry.     

桥环菁染料 1,1-((N)-甲基-4-吡啶基)-3-((N)-甲基-4-吡啶亚基)-4.5-二取代-1,4-环戊二烯甲基硫酸盐及具有不对称(N)-烷基的桥环菁染料

1,3-二(4-吡啶基)丙烷用硫酸二甲酯甲基化生成双吡啶盐(2),该吡啶盐(2)和α-二酮在碱性条件下缩合生成1-(N-甲基-4-吡啶基)-3-(N-甲基-4-吡啶亚基)-4,5-二取代-1,4-环戊二烯甲基硫酸盐(3),得率良好。1,3-二(4-吡啶基)丙烷用不同的卤代烷分步烷基化得不对称的双吡啶盐(5),(5)用上述方法和α-二酮反应得不对称桥环菁染料(6)。本工作还测定了桥环菁染料的可见和荧光光谱,并讨论了染料(3)的质子化过程和pK_b值。