Dicationic ((−)-sparteine)palladium-catalyzed enantioselective aldol reaction of aldehydes with 1-phenyl-1-trimethylsilyloxyethene, proceeding via a palladium enolate

A dicationic ((−)-sparteine)palladium complex underwent a superior catalytic enantioselective aldol reaction of aldehydes with 1-phenyl-1-trimethylsilyloxyethene performing satisfactorily, starting with ((−)-sparteine)PdCl₂ and AgSbF₆ as catalyst precursors (1 mol % loading) in the presence of 3 Å molecular sieves over the reaction.     

A facile non-oxidative method for synthesizing 1,3-disubstituted pyrroles from pyrrolidine and aldehydes

Reactions of pyrrolidine with 2 equiv of aldehydes without any catalyst in a pressurized vessel at 140–200 °C yielded 1,3-disubstituted pyrroles. -Branched aldehydes gave fairly good yields of the corresponding products by this method, which provides a facile non-oxidative procedure for synthesizing 1,3-dialkylpyrroles from inexpensive pyrrolidine and aldehydes.     

Azurocidin induces elastinolytic activity of medullasin

Addition of azurocidin, a protein in granulocytes similar to serine proteases but has no protease activity because of replacement of the active serine residue by glycine, to the incubation mixture containing medullasin induced elastinolytic activity of medullasin. Both medullasin and human leukocyte elastase were already shown to have negligible elastinolytic activity (Aoki, Y. et al. J. Biochem. 114, 122, 1993). Elastinolytic activity of medullasin was induced dose-dependently by the addition of azurocidin. Medullasin activity determined by using apo-ornithine transaminase or casein as substrates or that by N-methoxy-succinyl-(Ala)₂-Pro-Val-p-nitroanilide as substrate remained unchanged when azurocidin was added to the tube containing medullasin. Therefore, azurocidin is considered to cause an appearance of elastinolytic activity of medullasin without affecting the protease activity of it.     

PHOTOREACTIVATION ASSOCIATED WITH CHROMOSOMAL ABNORMALITY IN SEA URCHIN EGGS FERTILIZED WITH ULTRAVIOLET-IRRADIATED SPERM

Abstract— As a model for studies involving biologic systems, rates of hematoporphyrin and protopor-phyrin-sensitized photooxidation of tryptophan were measured in water-methanol mixtures. Absorption and fluorescence-emission spectra associated with solutions of porphyrins in different water-methano! mixtures were also examined. The optimal rate of photooxidation by hematoporphyrin occurred in 30% methanol; by protoporphyrin, in 60% methanol. Absorption spectra were examined to characterize dispersion of hematoporphyrin into monomeric form in 90% methanol, and the dimer formation which predominates in 30% methanol. With the more hydrophobic protoporphyrin, an absorption spectrum characteristic of drug monomer was seen in 100% methanol, a dimer spectrum was observed in 60% methanol. At methanol concentrations < 60%, we observed impaired photooxidation and another alteration in the absorption pattern apparently reflecting drug aggregation beyond the dimer stage. Fluorescence emission maxima of both porphyrins were blue-shifted with increasing solvent dielectric constant, but an additional blue shift was detected in an aqueous environment which was apparently related to porphyrin aggregation. Absorption and fluorescence-emission spectra appear helpful for characterizing environmental determinants of porphyrin-sensitized photooxidation.     

1,2-Diarylethylenediamines as pre-column fluorescence derivatization reagents in high-performance liquid chromatographic determination of catecholamines in urine and plasma

Meso- and dl-1,2-diarylethylenediamines (14 species) were evaluated for pre-column fluorescence derivatization reagents in the high-performance liquid chromatographic determination of catecholamines (norepinephrine, epinephrine and dopamine) in human urine and plasma. Of the compounds, meso-1,2-bis(4-methoxyphenyl)ethylenediamine was most preferable for all the catecholamines in terms of sensitivity and selectivity. The detection limit for each catecholamine is approximately 0.5 fmol in a 50-microliters injection volume.     

Spectrofluorimetric assay for acyl CoA-cholesterol acyltransferase

A sensitive assay for acyl CoA-cholesterol acyltransferase (EC 2.3.1.26) in rat liver microsomal and mitochondrial preparations is described. The lowered cholesterol concentration in the enzyme reaction with oleoyl CoA is determined spectrofluorimetrically by using the cholesterol oxidase/peroxidase/p-hydroxyphenylpropionic acid system. The assay requires as little as 20 μg of protein in the enzyme preparation.     

Separation and identification of Taxifolin 3-O-glucoside isomers from Chamaecyparis obtusa (Cupressaceae)

Taxifolin 3-O-glucoside isomers, [(2R, 3R)-, (2R, 3S)-, (2S, 3R)- and (2S, 3S)-] were isolated from leaves of Chamaecyparis obtuse (Cupressaceae). Their structures were elucidated on the basis of UV, MS, CD, 1H- and 13C-NMR spectral data, including 2D shift correlation. It was found that the compounds could be distinguished by the use of 1H- and 13C-NMR spectral data.