The kinetic (KIE) and solvent (SIE) isotope effect methods were used to investigate the mechanism of enzymatic hydroxylation of halogenated derivatives of l-tyrosine to l-DOPA catalyzed by the enzyme tyrosinase (EC 1.14.18.1). The values of deuterium KIE and SIE were obtained using the non-competitive method with spectrophotometric measurements. The Lineweaver-Burk plots were used for determina...

Activation of a strong aryl-Br bond of a halogenated vinylarene by nickel(0) is demonstrated in the presence of aryl-I containing substrates. eta2-Coordination of Ni(PEt3)2 to the C=C moiety of halogenated vinylarenes is kinetically preferable and is followed by an intramolecular aryl-halide bond activation process. This "ring-walking" process is quantitative and proceeds under mild reaction co...

Eight halogenated N,N ́-diphenethylethylenediamines were synthesized, characterized and evaluated for σ1 receptor binding affinity in vitro. Measurements of lipophilicity also were obtained. The substitution pattern on one of the aromatic rings remained constant as 3,4-dichloro, while the substituents on the other aromatic ring were varied to include fluorine, bromine or iodine in either the 2-,...

Several new synthetic methods for B-10 containing nucleoside derivatives have been developed. (1) The palladium-catalyzed coupling reaction of halogenated nucleoside derivatives with the aryltin compound having a boronic moiety proceeds chemoselectively at the C-Sn bond rather than the C-B bond to give boron-containing nucleoside derivatives. (2) The 1,2-addition reaction of the carbanions, gen...

The effect of copper and its compounds on halogenation dehalogenation aromatic will be discussed in the proposed article. Cu oxidized to appropriate halides is an effective catalyst not only for synthesis halogenated benzenes or their derivatives as desired organic fine chemicals, but also undesirable formation thermodynamically stable very toxic polychlorinated polybrominated such biphenyls, d...

BACKGROUND AND PURPOSE The aromatic amino acid L-Phenylalanine (L-Phe) significantly and reversibly depresses excitatory glutamatergic synaptic transmission (GST) via a unique set of presynaptic and postsynaptic mechanisms. Therefore, we hypothesized that endogenous derivatives of L-Phe, which display potent antiglutamatergic activity, may safely and efficaciously protect the brain during condi...

Burkholderia xenovorans LB400, Cupriavidus necator H850, and Pseudomonas pseudoalcaligenes KF707 are bacterial strains able to mineralize biphenyl and to co-oxidize many of its halogenated derivatives (PCBs). Only strain LB400 also mineralizes a few mono- and dichlorobiphenyls, due to the presence of a functioning chlorocatechol pathway. Here, we used a Tn5-based minitransposon shuttle system t...

Doliculide belongs to a group of marine cyclodepsipeptides with interesting biological properties. Apart from halogenated dipeptide, polyketide fragment containing 5 stereogenic centers is the most eye-catching element. This building block can be synthesized in highly stereoselective fashion using only one key reaction: Matteson homologation. straightforward protocol allows for introduction wid...