Oxidative cross-coupling reactions of substituted o-aminophenols were catalyzed by a commercial laccase to produce non-symmetrically substituted phenoxazinones for the first time. Identification by (1)H-, (13)C- and (31)P-NMR, and by HPLC-PDA and HPLC-MS/MS of exclusively two kinds of substituted phenoxazinones out of four potential heterocyclic frameworks was confirmed by a DFT study. The redo...

We have investigated the oxidative behaviour of natural compounds such as methyl abietate (1), farnesyl acetate (2), α-ionone (3), β-ionone (4), methyl linolelaidate (5), methyl linolenate (6) and bergamottin (7) with the oxidant system methyltrioxo-rhenium/ H2O2/pyridine. The reactions, performed in CH2Cl2/H2O at 25 °C, have shown good regio- and stereoselectivity. The oxidation products were ...

Antipyrine is a useful probe to evaluate variation of in vivo activities of oxidative hepatic drug-metabolizing enzymes. Here we describe an approach using C labeling and NMR spectroscopy for the direct and simultaneous analysis of major metabolites of antipyrine in human urine. [C-Methyl-C]antipyrine (500 mg) was dosed orally to human volunteers, and the post-dose urine was analyzed by 100-MHz...

1H NMR spectra were recorded of methanolic extracts of seven soybean varieties (Glycine max.), cultivated using traditional and organic farming techniques. It was possible to identify signals belonging to the groups of amino acids, carbohydrates, organic acids and aromatic substances in the spectra. In the aromatic zone, the isoflavone signals were of particular interest: genistein, daidzein, g...

The utility of infrared (IR) spectroscopy for the determination of strawberry ripeness has been successfully demonstrated. Transmission IR spectra were collected using dried liquid extracts from strawberry flesh. The overall IR feature provided fairly noticeable differences, and the ripeness stage was clearly identified using principal component analysis (PCA). Although all of the extracted com...

Alkali metal reduction of tungsten tetrachloride in the presence of excess trimethylphosphite and ethylene affords moderate yields of trans-tetrakis(trimethylphosphite)tungsten bis(ethylene). This easily prepared species bearing inexpensive ancillary ligands promotes the oxidative coupling of carbon dioxide and ethylene at ambient temperature to produce two isomeric tetrakis(trimethylphosphite)...

Metabolomic Analysis of Atlantic Blue Crab, Callinectes sapidus, Hemolymph Following 1 Oxidative Stress 2 3 Tracey B. Schock, David A. Stancyk, Lindy Thibodeaux, Karen G. Burnett, Louis E. 4 Burnett, Arezue F. B. Boroujerdi, Daniel W. Bearden 5 6 National Institute of Standards and Technology, Analytical Chemistry Division, Hollings 7 Marine Laboratory, Charleston, SC 29412 8 Grice Marine Labor...

The stereochemical determination of the potent antifungal agents leupyrrin A1 and B1 and the total synthesis of leupyrrin A1 are reported. The relative and absolute configuration was determined by a combination of high field NMR studies, molecular modeling, and chemical derivatization. The expedient total synthesis involves a one-pot sequential Zr-mediated oxidative diyne-cyclization/regioselec...

Seven new protopanaxatriol type saponins, 20S-sanchirhinosides A1 (1), A2 (2), A3 (3), A4 (4), A5 (5), and A6 (6), and sanchirhinoside B (7) were obtained as minor constituents from the root extract of Panax notoginseng (Burkill, F. H. Chen), which showed protection effects against antimycin A induced mitochondrial oxidative stress. Their structures were elucidated by chemical and spectroscopic...

The cobalt phenylthiolate complex, cis,mer-(PMe3)3Co(CH3)2SPh, was found to undergo competitive two-electron ethane reductive elimination and C-H bond cyclometallation. The thiophenolato bound cobaltacycle was generated via C-H bond oxidative addition to a five-coordinate intermediate followed by rapid methane elimination. A related cobalt isothiocyanate complex, cis,mer-(PMe3)3Co(CH3)2NCS, was...