A Convenient Method for the Phosphorylation of Phenols with Diethyl Cyanophosphonate

Phosphorylation of phenols with diethyl cyanophosphonate in methylene chloride solution at 0°C is an easy, rapid and good yielding reaction.     

Metal-oxygen-metal arrays in lamellar hybrid materials: cobalt and manganese 4-cyclohexene-1,2-dicarboxylates

We have obtained three layered hybrid materials from the hydrothermal reaction of 4-cyclohexene-1,2-dicarboxylic acid with Co and Mn salts: Co(C(8)H(8)O(4))[1], Mn(H(2)O)(C(8)H(8)O(4))[2], and Mn(4)(H(2)O)(C(8)H(8)O(4))(4).0.3(H(2)O)[3]. The structures for all materials were solved by single-crystal XRD ([1]P1, a=4.805(2) A, b=6.650(3) A, c=12.960(6) A, alpha=98.285(7) degrees, beta=98.986(7) degrees, gamma=95.689(7) degrees, V= 401.6(3) A(3), R(1)= 0.0438; [2] P2(1)/c, a=11.151(2) A, b=11.330(2) A, c=7.6560(15) A, beta=108.813(3) degrees , V=915.6(3) A(3), R(1)=0.0412; [3] P1, a= 11.412(3) A, b=12.136(4) A, c=13.809(4) A, alpha=104.703(6) degrees, beta=103.207(6) degrees, gamma=92.468(5) degrees, V=1790.6(9) A(3), R(1)=0.1056). While all three structures are two-dimensional overall, the metal-oxygen-metal dimensionality within the layers varies from isolated metal atoms in the case of [1] to 1D ribbons of vertex sharing MnO(6) octahedra [2] and 2D arrays of edge- and vertex-sharing polyhedra in [3].     

Heronapyrroles A-C: farnesylated 2-nitropyrroles from an Australian marine-derived Streptomyces sp

Chemical analysis of a marine-derived Streptomyces sp. (CMB-M0423) isolated from beach sand off Heron Island, Australia, yielded three new members of the rare pyrroloterpene biosynthetic structure class. Identified by detailed spectroscopic analysis as the first reported examples of naturally occurring 2-nitropyrroles, heronapyrroles A-C (1-3) displayed promising biological activity-with low to submicromolar IC(50) activity against Gram-positive bacteria but no cytotoxicity toward mammalian cell lines.     

Mixed fluoroamine complexes of chromium(III)

Summary Mixed difluoro(diamine)(diamme)chromium(III) complexes have been synthesized with ethylenediamine (en), 1,3 propanediamine(tn) and 1,2-cyclohexanediamine(chxn):trans-[CrF₂(aa)(bb)]Br (aa=en, bb=tn; aa=tn, bb= chxn) andcis-[CrF₂(aa)(bb)]Br (aa=en, bb=chxn). The corresponding fluoroaqua(diamine) (diamine)chromium(III) complexes have been prepared by acid hydrolysis as perchlorate or iodide salts. All have been characterized by chemical analysis, electronic and i.r. spectra and conductivity measurements.     

Determination of Aristocularine Enantiomers by Dispersive Liquid–Liquid Microextraction and Chiral High-performance Liquid Chromatography

Here is reported a novel analytical approach for the extractive separation and determination of enantiomeric ratios of aristocularine in bovine serum albumin. The results demonstrate suitable analytical performances. The separation was performed by chiral high-performance liquid chromatography with a 5-µm column using a mobile phase of 1:1 n-hexane:ethanol at a flow rate of 0.7?mL?min^?1 with ultraviolet–visible absorption, circular dichroism, and polarimetric detection. The enantiomers were eluted at 13.2 and 15.6?min for (+) and (?)-aristocularine, with a resolution of 1.58 and a separation factor of 1.27. The analytical parameters for the dispersive liquid–liquid microextraction were optimized; under these conditions, the extraction recoveries were from 88.6% to 93.9% for a two-step extraction. The precision, reported as the percent relative standard deviation, had values from 2.9% to 3.2% for 0.5?µg?mL^?1 of analyte for five replicate measurements using ultraviolet–visible absorption and circular dichroism detection. The limits of detection were between 0.05 and 0.08?µg?mL^?1 with enrichment ratios up to a value of 12.     

Design and synthesis of two epoxide derivatives from 3-ethynylaniline

For several years ago, several epoxide derivatives have been prepared using different methods; however, some protocols use reagents which could be expensive and require specials conditions. The aim of this investigation was to prepare two new epoxide-derivatives from 3-ethynylaniline using some reactions such as oximation, acetylation, 2 + 2 addition, functionalized chloroamides, and epoxidation via Darzens reaction. The chemical characteristics of epoxide derivatives were determinate through a spectroscopic and spectrometric analysis. In conclusion, it is noteworthy that the reactions used in this study do not involve expensive reagents or special conditions for the synthesis of epoxide derivatives.     

Complexes of osmium (III) obtained from OsO4 and ethylenethioureas. A kinetic study of the reduction in HClO4 solutions

Summary OsO₄ reacts with imidazolidine-2-thione and itsN-methyl andN-ethyl derivatives in acidified 11 vol. H₂O:EtOH to give [OsL₆]³⁺. Complexes obtained in the presence of HClO₄ or HBF₄ have been isolated as crystals and characterized by elemental analysis, i.r. spectroscopy and magnetic measurements.All the ligands bind the metal through the sulphur atom and the magnetic measurements are consistent with low spin osmium(III). The kinetics of [OsL₆]³⁺ formation has been followed spectrophotometrically. Thepseudo-first order rate constants are linear both with respect to the acid and the ligand concentrations, indicating that the kinetically significant process involves one proton and one molecule of the ligand. A comparison of these results with those obtained for the analogous reaction with thiourea is reported.     

Creating a Model of Acceptance: Preservice Teachers Interact With Non‐English‐Speaking Latino Parents Using Culturally Relevant Mathematics and Science Activities at Family Learning Events

The following describes a culturally relevant mathematics and science content program implemented by preservice teachers (PSTs) at Family Math/Science Learning Events (FM/SLEs) conducted through two different university programs in south Texas. These experiences are required course activities designed to inform PSTs of the importance of interacting with Latino families' culture and language in after school settings. Data were collected from elementary PSTs attending FMLEs and include interactions recorded during the FMLE and interviews with Latino non‐English‐speaking parents after the event. Anecdotal data were also included from parents' interviews collected during culturally relevant Family Science Learning Events. Researchers investigated the following questions: (1) what did Latino parents and PSTs report learning from the FMLE and, (2) how do perceptions toward Latino parents change when PSTs are given the opportunity to interact with and interview Latino parents? Results show that PSTs perceptions of Latino parents can be changed through these events. Implications for teacher preparation programs include providing PSTs with opportunities for participation in FM/SLEs that incorporate planning and teaching culturally relevant math and science activities. The following model of acceptance requires PSTs to identify and reconstruct misconceptions and perceptions of parents, especially non‐English‐speaking Latino parents.     

Design of an Optimal Grid for Finite Element Methods

ABSTRACT Finite element solutions of improved quality are obtained by optimizing the location of nodes of the finite element grid, while keeping the number of degrees of freedom fixed. The formulation of the grid optimization problem is based on the reduction of error associated with interpolation of the exact solution, using functions from the finite element space. Element sizes are selected as design variables: length in R1 and area in R2. Analytically derived optimality conditions are presented and an approximation to these conditions is introduced to obtain a set of operationally useful equations that can be used as guidelines for construction of improved grids. Example problems are given for illustration.     

Small generators of the ideal class group

Assuming the Generalized Riemann Hypothesis, Bach has shown that the ideal class group of a number field can be generated by the prime ideals of having norm smaller than . This result is essential for the computation of the class group and units of by Buchmann's algorithm, currently the fastest known. However, once has been computed, one notices that this bound could have been replaced by a much smaller value, and so much work could have been saved. We introduce here a short algorithm which allows us to reduce Bach's bound substantially, usually by a factor 20 or so. The bound produced by the algorithm is asymptotically worse than Bach's, but favorable constants make it useful in practice.