Three improved thiophosphoroselenenylation procedures of CH-acids, including derivatives malonic and acetyl-, phosphono-, 4-nitrophenyl- 3-pyridylacetic acids, have been described compared to previously reported thiophosphoroselenylation diethyl malonate using bis(disopropoxyphosphinothioyl)diselenide alone or with the aid methyl iodide. The use iodine makes it possible utilize both equivalents...

The role of H(2)O(2) and protein thiol oxidation in oxidative stress-induced epithelial paracellular permeability was investigated in Caco-2 cell monolayers. Treatment with a H(2)O(2) generating system (xanthine oxidase + xanthine) or H(2)O(2) (20 microM) increased the paracellular permeability. Xanthine oxidase-induced permeability was potentiated by superoxide dismutase and prevented by catal...

l-Glutamine d-fructose 6-phosphate amidotransferase (EC 2.6.1.16) was extracted and purified 600-fold by acetone fractionation and diethylaminoethyl cellulose column chromatography from mung bean seeds (Phaseolus aureus). The partially purified enzyme was highly specific for l-glutamine as an amide nitrogen donor, and l-asparagine could not replace it. The enzyme showed a pH optimum in the rang...

Copper complexes in combination with dioxygen are important as potential catalytic systems for regio- and stereoselective aerobic oxygenations of aromatic aliphatic C−H bonds at ambient temperatures. In that context we herein describe a copper(I) complex an imine ligand derived from (+)-camphor 2-(2-aminoethyl)pyridine forms bis(μ-hydroxido) dicopper upon reaction room temperature. It is detect...

Some aromatic aldehydes are subjected to react with urea (or thiourea) and acetyl acetone in a one-pot Biginelli-type cyclocondensation reaction to give 5-acetyl-4-aryl-6-methyl-1,2,3,4-tetrahydro-pyrimidines 2a-j. Aldehydes with ortho-hydroxy substituent namely salicylaldehyde and 2-hydroxy-3-methoxybenzaldehyde undergo Michael-type addition of the hydroxyl-proton to the C5−C6 double bond of t...