Chelation-assisted carbon-halogen bond activation by a rhodium(I) complex.

Chelation-assisted activation of C-X bonds (X = Cl, Br, and I) took place in the reaction of [Rh(PPh(3))(2)(acetone)(2)](+) and 2-(2-halophenyl)pyridine or 10-halobenzo[h]quinoline. A series of 16-electron five-coordinate cationic rhodium(III) monohalide complexes was synthesized at room temperature. Neutral octahedral rhodium(III) dihalide complexes were obtained when the corresponding cationic monohalide complexes were further heated in acetone.

An efficient synthesis of chiral phosphinyl oxide pyrrolidines and their application to asymmetric direct aldol reactions.

Chiral pyrrolidine-based phosphinyl oxides were synthesized and their performance as organocatalysts for asymmetric direct aldol reactions was evaluated. High enantioselectivities and diastereoselectivies were achieved for a range of cyclic ketones and aromatic aldehydes.

Synthesis, structures, and solution dynamics of palladium complexes of quinoline-functionalized N-heterocyclic carbenes.

A new type of quinoline-functionalized palladium N-heterocyclic carbene (NHC) complexes has been synthesized via silver transmetallation. The quinoline moiety was either directly attached to the imidazole ring or linked to it by a methylene group. NHCs with a methylene linker tend to form trans biscarbene complexes in the reaction of Pd(COD)Cl2, while NHCs without any linker form chelating NHC-quinoline (NHC-N) complexes.

Hydrogen bonding-assisted tautomerization of pyridine moieties in the coordination sphere of an Ir(I) complex.

Ir(I)-induced tautomerization of a pyridine moiety to a carbene in 2,3-bipyridyls has been successfully achieved where an amide group plays a key role as a hydrogen-bonding acceptor and the carbene tautomer is stabilized by both chelation effect and by hydrogen-bonding.

Purification and properties of a novel beta-glucosidase, hydrolyzing ginsenoside Rb1 to CK, from Paecilomyces Bainier.

A novel ginsenoside-hydrolyzing beta-glucosidase was purified from Paecilomyces Bainier sp. 229 by a combination of QSepharose FF, phenyl-Sepharose CL-4B, and CHT ceramic hydroxyapatite column chromatographies. The purified enzyme was a monomeric protein with a molecular mass estimated to be 115 kDa.

Surface modification of polyaniline using tetraethyl orthosilicate.

A well-dispersible conducting polyaniline/silica hybrid is prepared by the hydrolysis and condensation of tetraethyl orthosilicate (TEOS) on the surface of polyaniline in water/ethanol solution. It provides a simple and environmentally sound route for preparing the processable conducting polyaniline/silica hybrid at the nanometre level. The conductivity of polyaniline/silica hybrid is 2.

Purification method improvement and characterization of a novel ginsenoside-hydrolyzing beta-glucosidase from Paecilomyces Bainier sp. 229.

The purification method for a novel ginsenoside-hydrolyzing beta-glucosidase from Paecilomyces Bainier sp. 229 was successfully simplified by the application of microcrystalline cellulose (MCC) as a novel chromatographic matrix. Only two chromatographic steps, Q-Sepharose FF and MCC column in sequence, were required to purify the enzyme to apparent homogeneity.

Poly(aniline-2-sulfonic acid) modified multiwalled carbon nanotubes with good aqueous dispersibility.

Poly(aniline-2-sulfonic acid) (PASA)-modified multiwalled carbon nanotubes (MWNTs) were prepared by in situ oxidative polymerization. HRTEM images show that the PASA-modified MWNTs (PASANTs) are core (MWNT)-shell (PASA) tubular structures with a shell thickness of several nanometers. The strong interaction between the surface of the MWNTs and the conjugated structure of the PASA shell layer was proven by FTIR spectra.

Enhanced selectivity in the conversion of methanol to 2,2,3-trimethylbutane (triptane) over zinc iodide by added phosphorous or hypophosphorous acid.

The yield of triptane from the reaction of methanol with zinc iodide is dramatically increased by addition of phosphorous or hypophosphorous acid, via transfer of hydride from a P-H bond to carbocationic intermediates.

20-O-β-d-Xylopyranos-yl(1→6)-β-d-glucopyranosyl-20(S)-protopanaxadiol methanol solvate.

The title compound, C(41)H(70)O(12)·CH(4)O, was prepared by microbial transformation. Within the steroid skeleton of the mol-ecule, three six-membered rings exhibit a chair conformation, while the five -membered ring adopts an envelope conformation. The two pyranosyl rings also adopt chair conformations.

On the mechanism of the conversion of methanol to 2,2,3-trimethylbutane (triptane) over zinc iodide.

Methanol is converted to a mixture of hydrocarbons by reaction with zinc iodide at 200 degrees C with one highly branched alkane, 2,2,3-trimethylbutane (triptane), being obtained in surprisingly high selectivity. Mechanistic studies implicate a two-stage process, the first involving heterogeneously catalyzed formation of a carbon-carbon-bonded species, probably ethylene, that undergoes homogeneously catalyzed sequential cationic methylation to higher hydrocarbons. The first stage can be bypassed by addition of olefins, higher alcohols, or arenes, which act as initiators.

Intramolecular alkyne hydroalkoxylation and hydroamination catalyzed by iridium hydrides.

[reaction: see text] Iridium(III) hydrides prove to be air-stable active catalysts for intramolecular hydroalkoxylation and hydroamination of internal alkynes with proximate nucleophiles. The cyclization follows highly selective 6-endo-dig regiochemistry when regioselectivity is an issue.

Synthesis and evaluations of pentahydroxylhexyl-L-cysteine and its dimer as chelating agents for cadmium or lead decorporation.

N-(2,3,4,5,6-pentahydroxylhexyl)-L-cysteine (4) and N,N'-di(2,3,4,5,6-pentahydroxylhexyl)-L-cystine (5) were synthesized. As antagonists of cadmium or lead intoxication, they were found to be effective by oral administration on repeated exposure. The bioassay in vivo indicated that their cadmium-mobilizing potencies are significantly superior to those of N-acetyl-L-cysteine and their lead-mobilizing properties are equivalent to those of DL-penicillamine (DL-PA).

A rare eta2-butadienyl complex from an alkyne double insertion with double vinylidene rearrangement.

A rare eta2-butadienyl Ir(III) complex with a weak Ir...