The aim of the work is to investigate the ability of higher plants to absorb and detoxify environmental pollutants - aromatic compounds via aromatic ring cleavage. Transformation of 14C specifically labelled benzene derivatives, [1-6-14C]-nitrobenzene, [1-6-(14)C]-aniline, [1-(14)C]- and [7-(14)C]-benzoic acid, in axenic seedlings of maize (Zea mays L.), kidney bean (Phaseolus vulgaris L.), pea...

Hydrogen atom adducts to tryptophan were generated for the first time in the gas phase by collisional electron transfer to protonated tryptophan at 7170 eV kinetic energy. The radicals showed fast dissociations by C(α)-C(β) bond cleavage and cross-ring cleavages occurring on the 7.3 μs time scale. The mechanism of the C(α)-C(β) bond cleavage was explained by ab initio computational analysis of ...

It is known that the fluoro group has only a small effect on the rates of electrophilic aromatic substitutions. Imagine instead a carbon-fluorine (C-F) bond positioned tightly over the π cloud of an aryl ring-such an orthogonal, noncovalent arrangement could instead stabilize a positively charged arene intermediate or transition state, giving rise to novel electrophilic aromatic substitution ch...

The crystal structure of a colorless variant of green fluorescent protein (GFP) containing the Y66L substitution has been determined to 1.5 A. Crystallographic evidence is presented for the formation of a trapped intermediate on the pathway of chromophore maturation, where the peptide backbone of residues 65-67 has condensed to form a five-membered heterocyclic ring. The hydroxyl leaving group ...

in this study, b12n12 nano ring has been selected because it consist of four 6-side rings and polar bonds b-n which in comparison with non-polar bonds c-c, is more suitable for the study of the absorption of other compounds. so reactivity and stability of benzene alone and in the presence b12n12 nano ring field checked. to determine the non-bonded interaction energies between benzene and b12n12...

background chronic hepatitis c virus (hcv) is associated with extra hepatic autoimmune disorders, while peg-ifna-2a/rbv combination therapy may exacerbate these conditions. autoantibodies to cytoplasmic structures, called rod and ring particles (rr), have strong associations with these patients and are identified by hep-2 cells. objectives our purpose was to study the correlation of autoantibod...

Abstract α-Pyridones and α-pyrones are ubiquitous structural motifs found in natural products biologically active small molecules. Here, we report an Rh-catalyzed electrochemical vinylic C–H annulation of acrylamides with alkynes, affording cyclic good to excellent yield. Divergent syntheses α-pyridones imidates accomplished by employing N- phenyl tosyl as substrates, respectively. Additionally...

The reaction dynamics of ground state boron atoms, B(Pj), with acetylene, was reinvestigated and combined with novel electronic structure calculations. Our study suggests that the boron atom adds to the carbon–carbon triple bond of the acetylene molecule to yield initially a cyclic intermediate undergoing two successive hydrogen atom migrations to form ultimately an intermediate i3. The latter ...

A divergent approach was developed toward the total synthesis of taiwaniaquinoids. An advanced intermediate 5a with trans A/B ring junction was concisely assembled by employing a Bi(OTf)3-catalyzed cationic cyclization and a Wolff-type ring contraction as key steps. This common intermediate was readily converted to racemic taiwaniaquinones A and F and taiwaniaquinols B and D, respectively.

The stereoselective synthesis of (1S,2S,5R)-5-((4-methoxybenzyl)oxy)-2-methyl-8-methylene-1,2,4a,5,6,7,8,8a-octahy-dronaphthalene-1-carboxylic acid (2) is described, which comprises the bicyclic core structure natural product amycolamicin (1). ring-system was established via an intramolecular Diels-Alder reaction a triene carrying SuperQuat chiral auxiliary. latter could be readily removed by m...