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N,N-Dialkylarylamines react with trimethyl orthoformate and TiCl4 under ambient conditions to give the corresponding formyl derivatives in 75-89% yields, whereas the corresponding arylated products are obtained from benzyl ethers and acetals in 42-78% yields.  相似文献   
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Summary Reduction of anhydrous FeCl3 in THF with sodium naphthalenide under a CO atmosphere at room temperature leads directly to Na2Fe(CO)4, which on reaction with alkyl bromides gives the corresponding aldehydes, ketones and carboxylic acids under appropriate conditions.  相似文献   
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The reactions of arylacetic acid esters with tertiary arylamines in the presence of TiCl4 give α-arylated products in 65-90% yields, as well as 10-20% yields of the corresponding benzidines.  相似文献   
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Electronic and structural factors controlling the competition between 5-exo-dig and 6-endo-dig cyclizations of sp2-radicals were analyzed using a combination of available experimental data and computation. Although the stereoelectronically favored 5-exo pathways usually has the lower activation energy, formation of a new aromatic ring not only makes the 6-endo process favorable thermodynamically in conjugated systems but also lowers its activation barrier to the extent where the 5-exo/6-endo selectivity is controlled by subtle factors such as the different sensitivity of the two pathways to strain effects in polycyclic systems. In particular, the stronger sensitivity of the 5-exo pathway to strain leads to a crossover in selectivity. The 6-endo cyclization is kinetically favored in smaller (and strained) cycles, whereas the 5-exo cyclization has lower barriers in the larger rings.  相似文献   
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Mixed crystals of 0.1 and 0.25 zinc magnesium ammonium sulphate were grown by slow evaporation of aqueous solution at room temperature. The bright and transparent crystals obtained were characterized by thermal (TG–DTA), FTIR and XRD analyses. A fitting decomposition pattern for the compound was formulated on the TG curve which shows two stage mass losses between 133 and 478.75 °C. In this temperature range, DTA curve shows exothermic peaks supporting the formulated decomposition pattern. The FTIR spectra show the vibration frequencies due to the formation of zinc magnesium ammonium sulphate mixed crystals. Detailed structural analysis of the compound is under progress.  相似文献   
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Water blown rigid polyurethane foams (PUF) with organoclay/organically modified nanoclay (ONC) were prepared and their properties such as density, mechanical, morphological, insulation, thermal and flame retardant properties were studied. In this investigation, the ONC content was varied from 1 to 10 parts per hundred of polyol (php) by weight. It was observed that the compressive strength of ONC filled PUF increased up to 3 php of ONC loading and then it decreased. Wide angle X-ray diffraction and transmission electron microscopy studies indicated the exfoliated dispersion of ONC in PUF. The thermal conductivity of ONC filled PUF decreases up to 5 php and then increases. The glass transition temperature (Tg) of PUF decreases on loading of ONC. The TGA analysis shows that there is slight increase in degradation temperature with increase in ONC loading. The flame retardant properties (LOI and flame spread rate) are improved slightly on addition (3 php) of ONC filled PUF.  相似文献   
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The title compound of l-alanine thiourea, a semi organic material, has been grown from slow evaporation solution growth technique at room temperature. It is a potential material for nonlinear optical applications. The grown single crystals have been analyzed using powder X-ray diffraction. It belongs to monoclinic crystal system, and its lattice dimensions were determined. The presence of functional groups was identified from FTIR spectral analysis. The title compound has good optical transmission in the entire visible region. Thermal stability of the grown crystal was investigated by thermogravimetric and differential thermal analysis.  相似文献   
10.
Using anthraquinone as a useful synthetic scaffold and the ability of anthraquinone to form stable intermediate reduction products (i.e. anthrones and anthranols), we have synthesized a wide variety of constrained crown ring systems where the receptor includes several types and patterns of Lewis bases that can tune receptor selectivity for different metal cations. Constrained crown ring systems are defined as macrocycles that contain an intraannular heteroatom, in addition to the normal peripheral Lewis bases that compose the outer ring of the macrocycle. These fluorescence sensors predominantly utilizes the internal charge transfer mechanism to promote fluorescence, but has also led to the development of new photophysical mechanisms, i.e. metal-mediated tautomerization, to selectively detect Zn(II) ion in solution. We are currently pursuing a number of synthetic avenues to incorporate new functional groups and lumophores such that a myiad of different photophysical mechanisms under optimal conditions can be employed to improve solubility, sensitivity and take advantage of the cross pollination of electrochemistry and fluorescence spectroscopy with these sensors which incorporate closely integrated electrochemical, fluorescence and receptor subunits.  相似文献   
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