Synthesis of 4'-(2,6,6-trimethyl -2-cyclohexen-1-yl) -3'-buten-2'-ketoxime-N-O-alkyl ethers

4'-(2,6,6-Trimethyl-2-cyclohexen-1-yl)-3'-buten-2'-ketoxime-N-O-alkyl ethers have been synthesized starting from alpha-ionone, separated into their E and Z isomers and characterized on the basis of (1)H-NMR and mass spectra.     

An efficient route for commercially viable syntheses of furan- and thiophene-anellated β-hydroxychalcones

An efficient route for the syntheses of β-hydroxychalcones containing benzofuran and benzothiophene rings is described. Isoxazolines obtained from oxime-olefin cycloadditions were reduced under pressure to a mixture of products. Isoxazoles obtained from Claisen aroylation of an ester and subsequent acid cyclization, or from isoxazolines via DDQ-mediated dehydrogenation, were subjected to catalytic hydrogenation followed by hydrolysis to afford 1-phenyl-3-(benzofuran-5-yl)-1,3-diketone and 1-phenyl-3-(benzothiophene-5-yl)-1,3-diketones in very good yields.     

Kinetics and mechanism of reaction between aminopolycarboxylatomanganate(III) complexes and cyanide ions: a reinvestigation of the MnCyDTA-CN− reaction

Summary Reactions between CN^– and complexes of Mn^III withtrans-1, 2-diaminocyclohexanetetraacetic acid (CyDTA) and hydroxyethylethylenediaminetriacetic acid (HEEDTA) have been studied spectrophotometrically at the _maxS of their respective hydroxo species under pseudo-first-order conditions. The forward reaction is found to be first-order with respect to both the metal complex and [CN^–].The kinetics of the reverse reaction, i.e. the reaction between [Mn(CN)₆]^3– and CyDTA^4– or HEEDTA^3– taken in large excess) have been followed spectrophotometrically. In both systems, the reactions follow first-order kinetics each in [Mn(CN)₆]^3– and the respective ligand concentration and an inverse first-order dependence in [CN^–]. A six step mechanism is proposed for the forward reaction where the fifth step is the rate-determining one. pH, ionic strength and temperature dependences have been studied for both systems.     

Kinetics and mechanism of ligand substitution of mono(polyamine)-nickel(II) complexes with 4-(2-pyridylazo)resorcinol

Summary The kinetics and mechanism of ligand substitution reactions of tetraethylenepentamine nickel(II), Ni (Teren), and triethylenetetraamine nickel(II), Ni(Trien), with 4-(2-pyridylazo)resorcinol (parH₂) have been studied spectrophotometrically at I=0.1 M (NaClO₄) at 25°C. In both systems two distinct reaction steps are observed. The rapid first step follows the rate law d[Ni(Polyamine)(ParH₂)]/dt=k₁ [Ni(Polyamine)] [ParH₂]. The formation of ternary complexes of Ni (Polyamine) with ParH₂ has been investigated under second order equal concentration conditions. The values of second order rate constants for the Trien and Teren reactions are (2.1±0.2)×10⁴ M^–1s^–1 and (7.8±0.6)×10³ M^–1s^–1 respectively at pH=9.0, I=0.1 M and 25°C.The rate law for the second step may be written as d[Ni(Par)₂]/dt=k₂[Ni(Polyamine)(ParH₂)]. Values of k₂ for the Trien and Teren systems are (2.5±0.1)×10^–4 s^–1 and (4.76±0.3)×10^–5 s^–1 respectively.     

New approach to the simultaneous analysis of catecholamines and tyrosines in biological fluids

New high-performance liquid chromatographic (HPLC) methods with amperometric-CoulArray detection were developed for simultaneous analyses of norepinephrine, epinephrine, L-DOPA, dopamine, 3-nitrotyrosine, m-, o-, and p-tyrosines. Overall, detection limit was in the low pmol range with amperometry, and in the low fmol range for the CoulArray method. Linear (r2 = 0.99) detector performances were observed in the ranges of 2-200 pmol with amperometry, and 0.2-20 pmol for the CoulArray method. Analytical precision values were better than 80 and 95% for HPLC-amperometry and HPLC-CoulArray method, respectively. These methods offer sensitivity, specificity, minimal sample requirement, and especially the HPLC-CoulArray method allows simultaneous assessment of various similar biomolecules.     

The transverse force on a spinning porous sphere at small Reynolds number

This paper deals with the problem of the flow about a spinning porous sphere moving in an incompressible viscous fluid. The effect of permeability on the flow has been studied analytically at low Reynolds number by the method of matched asymptotic expansions. It turns out that the permeability on the drag force up to 0(R) reduces the effective radius by a factor (2+K/a ²)^–1,K being the permeability associated with the porosity of the reduced radius of the sphere. Further, it is found that the permeability affects the lift forceF _L , which is orthogonal to its direction of motion. The ratio of the effective angular velocity and actual angular velocity decreases forK>0.25. ForK=0.25 there is no spinning effect on the sphere.

---

Zusammenfassung Diese Arbeit behandelt die Strömung um eine rotierende poröse Kugel in einer zähen inkompressiblen Flüssigkeit. Der Einfluss der Durchlässigkeit wurde für kleine Reynolds-Zahlen mit Hilfe von angepassten asymptotischen Entwicklungen bestimmt. Es wurde gefunden, dass die Durchlässigkeit den Widerstand O(R) vermindert, und die Auftriebskraft senkrecht zur Bewegungsrichtung beeinflusst.

     

Packing 1×2×4 bricks in a cubical box

Given a cubical box C_2n+1 of side 2n+1 and a supply of 1×2×4 bricks, it is proved that if n≥2, then

(A1)

one can pack bricks for n odd, and bricks for n even,

(A2)

the capacity of C_2n+1 is , and if n≡1 or 2 (mod4), this upper bound for the capacity can be reduced by 1.

     

A Xanthan-Gum-Stabilized PEG-Conjugated Nanocurcumin Complex: Telescoping Synthesis for Enhanced Permeation Potential

We report a facile room temperature telescoping synthesis of a nanocurcumin complex with 17.5-fold permeation enhancement as determined by comparative in vitro permeation study with raw curcumin. The permeation results were further validated with in silico drug absorption prediction using ADMET predictors.