一个计算次甲基质子NMR化学位移的经验式

本文提出了一个计算次甲基质子NMR化学位移的经验式δ_CHXYZ=δ_(CH3)2CHZ+△_xy主要用来计算那些Bell、Bowles和Senese关系式不适用的、含有无去屏蔽作用的次甲基质子体系中次甲基质子的化学位移。     

A note on bounds for the derivatives of continued fractions

Although it is difficult to differentiate analytic functions defined by continued fractions, it is relatively easy in some cases to determine uniform bounds on such derivatives by perceiving the continued fraction as an infinite composition of linear fractional transformations and applying an infinite chain rule for differentiation.     

Identities for the Chebyshev functional involving derivatives of arbitrary order and applications

We generalize the identities of J. Pe?ari? and A.M. Fink for the Chebyshev functional. The identities are shown to be very useful in establishing various bounds for the Chebyshev functional.     

The Explicit Determination of the Logarithm of a Tensor and Its Derivatives

The logarithm of a tensor is often used in nonlinear constitutive relations of elastic materials. Here we show how the logarithm of an arbitrary tensor can be explicitly evaluated for any underlying space dimension n. We also present a method for the explicit evaluation of the derivatives of the logarithm of a tensor.      

An inclusion formula for derivatives

Often an estimate of a derivative or its range over an interval is desired rather than the derivative itself. Error terms for numerical approximations may sometimes be rigorously estimated in terms of a number of values of the derivative and a majorant. We indicate this and propose a technique for the strict estimation of the values of the derivatives in terms of central differences of the function and its majorant. We stress strictness and accept less accuracy.     

ACID-CATALYZED ADDITION OF N-HYDROXYUREA TO 1-ARYL ALCOHOL DERIVATIVES: A NEW SYNTHESIS OF ZILEUTON

A highly efficient synthesis of Zileuton is described in which the key step involves a site-specific alkylation of hydroxyurea under acid catalysis. Various aryl alcohol electrophiles were tested and the reaction was found to be highly substrate-specific, favoring benzothiophene and benzofuran-based alcohols.     

Alder-ene reaction of aryne with olefins

A novel intermolecular Alder-ene reaction based on aryne and olefins was developed. We performed this transformation under mild conditions such as at room temperature, and this reaction displayed high selectivity and good yields only in the presence of CsF. Hence, the intermolecular Alder-ene reaction of aryne with olefins provides an effective route to synthesize derivatives of olefins.     

Efficacy of Organophosphorus Derivatives Containing Substituted Chalcone Thiosemicarbazones and Dithiocarbazates Against Fungal Pathogens of Sugarcane

Ten novel organophosphorus derivatives have been prepared by the reactions of O,O-diethylchlorophosphate with two important series of substituted chalcones viz., substituted chalcone thiosemicarbazones and substituted chalcone dithiocarbazates. The derivatives have been characterized on the basis of analysis and spectral (IR, 1 H NMR) data. Fungicidal activity of these derivatives against Colletotrichum falcatum , Fusarium oxysporum , and Curvularia pallescens have been evaluated. The screening results have been correlated with the structural features of the tested compounds. Organophosphorus derivatives containing 2,2'-dihydroxybenzalacetophenone thiosemicarbazone, 2-chlorobenzal-2'-hydroxyacetophenone thiosemicarbazone, 2-chlorobenzal-2'-hydroxy acetophenone-S-benzyldithiocarbazate proved more active than some prevalent commercial synthetic fungicides.     

Synthesis, Characterization and Structural Determination of Ferrocene Derivatives Linked with Benzo[b]pyrans ——2-Amino-7,7-dimethyl-4-ferrocenyl-5-oxo-5,6, 7,8-tetrohydro-4H-chromene-3-carbonitrile

The title compound (C22H22N2O2Fe·CH3OH) was synthesized via a one-pot proce- dure from ferrocenylaldehyde, malononitrile and 5,5-dimethyl-1,3-cyclohexanedione using room temperature ionic liquid and pyridine as the catalysts, and characterized by elemental analysis, IR and 1H NMR. The structure was determined by X-ray single-crystal diffraction. The crystal belongs to monoclinic system, space group P21/n, with a = 9.7085(15), b = 22.951(4), c = 9.987(2) A, β = 112.494(3)°, V = 2055.9(6) A3, Z = 4, Mr = 402.28, Dc = 1.403 g/cm3, μ = 0.759 mm-1, F(000) = 868, the final R = 0.0536 and wR = 0.1449 for 4202 observed reflections with I > 2σ(I). The supramolecular single-helix chain of the title compound is formed by linking the building units with the hydrogen bond between N1 and N2. The adjacent chains are connected to a 2D layer by the hydrogen bond between N1 and O1. The adjacent layers are further linked by van der waals’ force. The CH3OH molecule is trapped in the interlayer.     

The synthesis of functional derivatives of the [1-CB9H10] anion by Brellochs reaction

Reactions of decaborane with various aldehydes in alkaline media were studied. The reactions with HCOH and 2-MeOC₆H₄CHO give the corresponding arachno-carboranes [6-R-arachno-CB₉H₁₃]⁻ (R = H, C₆H₄-2-OMe), whereas the reactions with C₆H₅CHO, 4-BrC₆H₄CHO, 4-MeCONHC₆H₄CHO, and 2-SC₄H₃CHO result in the nido-carboranes [6-R-nido-CB₉H₁₁]⁻ (R = C₆H₅, C₆H₄-4-Br, C₆H₄-4-NHCOMe, 2-SC₄H₃). Both the arachno- and nido-carboranes can be easily oxidized with elemental iodine in an alkaline aqueous solution giving the corresponding closo-derivatives [2-R-closo-2-CB₉H₉]⁻. These closo-2-isomers, under heating in solution, undergo rearrangement to more thermodynamically favorable closo-1-isomers [1-R-closo-1-CB₉H₉]⁻. The structure of (Bu₄N)[1-(4-BrC₆H₄)-1-CB₉H₉] was determined using single crystal X-ray diffraction.