Resolution of N-acyl-1-naphthylalkylamide on amide and sulfonamide-derived π-acidic chiral stationary phases

Two π-acidic chiral stationary phases (CSP 3, CSP 4) were prepared by connecting the N-3,5-dinitrobenzamide derivative or 2,4-dinitrobenzenesulfonamide derivative of (S)-leucinol to silica gel through the carbamate linkage. The CSPs were applied in resolving seven racemic N-acyl-1-naphthylaminoalkanes by chiral HPLC, and the chromatographic resolution results were compared. From the comparison of the resolution results of the two CSPs, the role of amide and sulfonamide group in each chiral selector of CSP 3 and CSP 4 and an iso-butyl and phenyl group on the chiral center of each CSP 2 and CSP 3 were explained.     

Role of titania incorporated on activated carbon cloth for capacitive deionization of NaCl solution

Adsorption isotherms of NaCl on activated carbon cloth (ACC) and titania-incorporated activated carbon cloth (Ti-ACC) under an electric field were investigated to deduce the role of titania in capacitive deionization (CDI) of NaCl. Electrosorption of NaCl on the ACC was significantly increased by titania incorporation, whereas its physical adsorption was considerably decreased, resulting in an improved performance of the Ti-ACC as a CDI electrode. Langmuir isotherms based on a localized and fixed amount of adsorption were suitable for the simulation of electrosorption and physical adsorption of ions on the ACC electrodes. The variances of q(m) and b of Langmuir isotherms with electric potential indicate increases in the number of ions per adsorption site and in electrosorption strength of ions by titania incorporation. A cyclic voltammetric study for ion adsorption on ACC electrodes confirms the reversibility between electrosorption and desorption of ions, regardless of titania incorporation.     

Cubic Ia3d large mesoporous silica: synthesis and replication to platinum nanowires,carbon nanorods and carbon nanotubes

A new synthesis route to high-quality large mesoporous cubic Ia3d silica is reported, utilizing a triblock copolymer (EO20PO70EO20)-butanol mixture for the structure direction in aqueous solution.     

Thermal and electrochemical characteristics of plasticized polymer electrolytes based on poly(acrylonitrile-co-methyl methacrylate)

The thermal and electrochemical characteristics of plasticized polymer electrolytes composed of poly(acrylonitrile-co-methyl methacrylate) [P(AN-co-MMA)], a plasticizer [a mixture of ethylene carbonate and propylene carbonate], and LiCF₃SO₃ were investigated. The incorporation of a MMA unit into the matrix polymer was effective for an increase in the compatibility between the matrix polymer and the plasticizer. The comparative investigation of the interfacial resistance of the Li/polymer electrolyte/Li cell for the PAN-based and the P(AN-co-MMA)-based polymer electrolytes showed that the MMA unit could improve the stability of the polymer electrolyte toward the Li electrode, which is probably due to the enhanced adhesion of the polymer electrolyte to the Li electrode. Received: 14 July 1997 / Accepted: 14 May 1998     

Enantioseparation of racemic N-acylarylalkylamines on various amino alcohol derived tau-acidic chiral stationary phases

Five tau-acidic chiral stationary phases (CSPs), CSP 4, CSP 5, CSP 6, CSP 7 and CSP 8, were prepared by connecting the N-(3,5-dimethylbenzoyl) derivative of (R)-alaninol, (S)-leucinol, (1S,2R)-ephedrine and (S)-tert-leucinol and the O-(3,5-dinitrobenzoyl) derivative of (R)-phenylglycinol to silica gel through a carbamate or urea linkage. The CSPs were applied to the resolution of various racemic N-acyl-1-naphthylaminoalkanes by chiral HPLC, and the chromatographic resolution results were compared with those of previously reported CSPs (CSP 2, CSP 3), which are derived from N-(3,5-dinitrobenzoyl)-(1S,2R)-norephedrine and N-(3,5-dinitrobenzoyl-(R)-phenylglycinol. Based on a comparison of the resolution results for each CSP, the role of each functional group on the five chiral selectors is explained.     

Electronic and vibrational spectroscopy of cis-beta-[CrCl(2)(1,4,7,11-tetrazaundecane)chromium(III) perchlorate

The sharp-line absorption spectrum of cis-beta-[CrCl(2)(2,2,3-tet)]ClO(4) (2,2,3-tet: 1,4,7,11-tetraazaundecane) has been measured between 13,000 and 16,000 cm(-1) at 5K. The 77K emission, 298 K infrared and visible spectra have also been measured. The zero-phonon band in the highly resolved absorption spectrum splits into four components. The vibrational intervals of the electronic ground state were determined from the far-infrared and emission spectra. The 10 electronic bands due to spin-allowed and spin-forbidden transitions were assigned. Using the observed transitions, a ligand field analysis has been performed to probe the ligand field properties of coordinated atoms in the title chromium(III) complex. The X-ray crystal structure at low-temperature was determined to help in assigning the sharp-line electronic transitions.     

Trichostatin A-mediated upregulation of p21(WAF1) contributes to osteoclast apoptosis

Histone deacetylase inhibitors (HDIs), a new class of anti-cancer agents, have been reported to suppress formation of osteoclast precursors and their fusion into multinucleated cells. However, little is known about the effect of HDIs on mature osteoclasts, which may have significance for their therapeutic use. Here, we demonstrate a novel action of HDIs on osteoclast apoptosis. Primary multinucleated mature osteoclasts were prepared from mouse bone marrow cells. Treatment of osteoclasts with the HDI trichostatin A (TSA) caused apoptosis, as confirmed by annexin V staining and caspase activation. TSA caused the upregulation of p21WAF1 in osteoclasts. To understand the role of p21(WAF1) upregulation in TSA-treated osteoclasts, shRNA against p21(WAF1)-containing lentivirus was introduced into osteoclasts. The suppression of p21(WAF1) decreased TSA-directed osteoclast apoptosis. Collectively, our results provide evidence that TSA causes osteoclast apoptosis, which involves, in part, TSA-induced upregulation of p21(WAF1), and strongly supports HDIs as potential therapeutic agents for excessive bone resorption.     

Stereospecific synthesis of C2 symmetric diamines from the mother diamine by resonance-assisted hydrogen-bond directed diaza-Cope rearrangement

Sixteen diphenylethylenediamine analogues including those with electron donating, electron withdrawing, and sterically bulky substituents have been prepared in good overall yields (70-90%) and in enantiomerically pure form (>99% ee) by diaza-Cope rearrangement reaction. A single chiral mother diamine, ((R,R)-1,2-bis-(2-hydroxyphenyl)-1,2-diaminoethane), is reacted with appropriate aldehydes to form the initial diimines that rearrange to give all the product diimines in the (S,S) form. The daughter diamines are obtained by hydrolysis of the product diimines. Density functional theory computation shows that resonance-assisted hydrogen-bond is the main driving force behind all the rearrangement reactions. Chiral high performance liquid chromatography and circular dichroism spectroscopy show that the highly stereospecific rearrangement reactions take place with apparent inversion of stereochemistry.