One-pot, four-component procedure for the synthesis of a small library of new chiral spiro- oxindolopyrrolidines with high regio-, diastereo- (>99:1 dr), and enantioselectivity (up to 80% ee) is described. In this process, the regio- and stereochemical 1,3-dipolar cycloaddition of azomethine ylides, which were generated insitu by the reaction of isatin derivatives and sarcosin,with optically ac...

The title compound, C(9)H(7)ClN(2)O(2), was prepared by reaction of methyl 4-chloro-3-(prop-1-yn-yl)picolinate with hydroxy-l-amine in MeOH/KOH solution. The two essentially planar mol-ecules which make up the asymmetric unit have almost identical geometries and and are linked into dimeric aggregates via pairs of O-H⋯O hydrogen bonds. These aggregates have almost perfect inversion symmetry; how...

Human dipeptidyl-peptidase III (h.DPP III) is a zinc-exopeptidase that hydrolyses dipeptides from the N-terminus of its substrates. Its mechanism of action was assumed to be similar to that of thermolysin, but was never thoroughly investigated. This study presents the first insight into the reaction mechanism of h.DPP III, determined on the model and real (hydrated enzyme with Leu-enkephalin bo...

According to a quantum chemical analysis based on energy optimized M NDO calculations the 1.5-sigmatropic reaction of cyclopentadienylphosphanes can occur via a transition state either with retention or inversion of configuration at phosphorus, depending on the ligands within the PR2 fragment. Electropositive R favour inversion and electronegative R retention of configura­ tion at phosphorus. I...

invert sugar is the result of sucrose of hydrolysis of sucrose by acid or enzyme, that is, the splitting of sucrose molecules into their glucose and fructose components.invert sugar is used in different industries such as; food industry, soft drinks and pharmaceutical, due to its special characteristics such as; sweetness level, moisture ability’s property, crystallization level and special tas...

Seven subjects with normal joints were tested for active and passive position sense of ankle inversion, peroneal reflex reaction time to sudden ankle inversion, and postural stability during single-leg stance. The tests were performed before and after regional block of the ankle and foot with local anaesthetic. Passive position sense, assessed with the muscles relaxed, was greatly impaired by a...

Here, we apply the harmonic Fourier beads (HFB) path optimization method to study chemical reactions involving covalent bond breaking and forming on quantum mechanical (QM) and hybrid QM∕molecular mechanical (QM∕MM) potential energy surfaces. To improve efficiency of the path optimization on such computationally demanding potentials, we combined HFB with conjugate gradient (CG) optimization. Th...

in this research we have studied tabriz temperature inversion using radio-sound information, during the 2004-2008 periods in daily, monthly and seasonally scales. produced data associated with temperature inversion daily of the surface (2 meters) to 700 h.pa. several different measures are used, including the height of the base and the height of the top of the inversion, the temperature at the ...