Novel Copolymers of 4-Fluorostyrene. 9. Some Ring-Disubstituted 2-Phenyl-1,1-dicyanoethylenes

Novel copolymers of trisubstituted ethylene monomers, ring-disubstituted 2-phenyl-1,1-dicyanoethylenes, RC₆H₃CH=C(CN)₂ (where R = 3-Br-4-CH₃O, 5-Br-2-CH₃O, 2-F-5-CH₃, 2-F-6-CH₃, 3-F-2-CH₃, 3-F-4-CH₃, 4-F-2-CH₃, 4-F-3-CH₃) and 4-fluorostyrene were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator (ABCN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, ¹H and ¹³C-NMR. The order of relative reactivity (1/r ₁) for the monomers is 3-F-4-CH₃(1.64) > 5-Br-2-CH₃O (1.62) > 3-Br-4-CH₃O (1.36) > 4-F-2-CH₃(1.3) > 4-F-3-CH₃(1.26) > 3-F-2-CH₃(1.11) > 2-F-5-CH₃ (0.98) > 2-F-6-CH₃ (0.97). High T_g of the copolymers, in comparison with that of poly(4-fluorostyrene) indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 290–400°C range with residue, which then decomposed in 400–800°C range.     

Effect of Anomeric Linkage on the Sialylation of Glycosides by Cells

The synthesis of sialylated glycosides using saccharide primers and cells was investigated. α · and β · Saccharide primers were chemically synthesized and introduced into B16 melanoma cells to prime oligosaccharide synthesis. Incorporation of α‐ and β‐dodecyl lactosides into B16 cells resulted in the sialylation of the galactose residue to give GM3‐type oligosaccharides. The β‐dodecyl galactoside primer was sialylated but the α‐dodecyl galactoside primer was not. Both the α‐ and β‐dodecyl glucoside primers were not elongated. In the glycosylation of primers by cells, this research confirmed that sialyl transferases tolerate acceptor modifications and are permissive to primer elongation regardless of the α‐ or β‐linkage to the aglycon unit. However, the presence of the terminal galactose residue that is β‐linked to the adjacent saccharide or aglycon unit is essential for sialylation by cellular enzymes to occur.     

Enhancement of Solar Hydrogen Evolution from Water by Surface Modification with CdS and TiO2 on Porous CuInS2 Photocathodes Prepared by an Electrodeposition–Sulfurization Method

Porous films of p‐type CuInS₂, prepared by sulfurization of electrodeposited metals, are surface‐modified with thin layers of CdS and TiO₂. This specific porous electrode evolved H₂ from photoelectrochemical water reduction under simulated sunlight. Modification with thin n‐type CdS and TiO₂ layers significantly increased the cathodic photocurrent and onset potential through the formation of a p–n junction on the surface. The modified photocathodes showed a relatively high efficiency and stable H₂ production under the present reaction conditions.     

Analytical separation of tea catechins and food-related polyphenols by high-speed counter-current chromatography

High-speed counter-current chromatography (HSCCC) using the type-J coil planet centrifuge was applied to compositional analysis of tea catechins and separation of other food-related polyphenols. The HSCCC separation of nine different standard compounds and those from extracts of commercial tea leaves was performed with a two-phase solvent system composed of tert-butyl methyl ether-acetonitrile-0.1% aqueous trifluoroacetic acid (TFA) (2:2:3, v/v/v) by eluting the upper organic phase at a flow rate of 2 ml/min. The main compounds in the extract of non-fermented green tea were found to be monomeric catechins, their galloylated esters and caffeine. In addition to these compounds, oxidized pigments, such as hydrophobic theaflavins (TFs) and polar thearubigins (TRs) were also separated and detected from the extracts of semi-fermented oolong tea and fermented black tea. Furthermore, several food-related polyphenols, such as condensed catechin oligomers (procyanidins), phenolic acids and flavonol glycosides were clearly separated under the same HSCCC condition. These separation profiles of HSCCC provide useful information about the hydrophobic diversity of these bioactive polyphenols present in various types of teas and food products.     

Procedure for increasing the detection responses of estrogens in LC–MS based on introduction of a nitrobenzene moiety followed by electron capture atmospheric pressure chemical ionization

A practical procedure for determining estrogens in biological fluids has been studied using liquid chromatography–electron capture atmospheric pressure chemical ionization–mass spectrometry combined with derivatization. Among the commercially available reagents (4-nitrobenzoyl chloride, 2,4-dinitrofluorobenzene, 4-nitrobenzenesulfonyl chloride and 4-nitrobenzyl bromide), 4-nitrobenzenesulfonyl chloride was of the most practical use; it rapidly and quantitatively reacted with estrogens and increased the detection responses by 8–23 times. The derivatization method allowed the reproducible and accurate quantification of serum and urine estrone and estradiol of a pregnant woman, which is useful for diagnosis of the fetoplacental function, with small amounts (10 μl) of sample and a simple pretreatment procedure. Tatsuya Higashiis Associate Professor of the Laboratory of Clinical Analytical Sciences (Professor Kazutake Shimada’s research group) at the Graduate School of Natural Science and Technology of Kanazawa University. He received the Japan Society for Analytical Chemistry Award for Young Scientists in 2003 and the Pharmaceutical Society of Japan Award for Young Scientists in 2006. His current research interests are the development of methods for increasing sensitivity in LC-MS to detect and characterize trace amounts of biologically active steroids, such as estrogens, androgens and neuroactive steroids.     

Saccharide-branched Cyclodextrins as Targeting Drug Carriers

A synthetic series of heptakis-galactose-branched cyclodextrins (termed CDs) having a longer spacer arm using two amino-caproic acids as an enlarging unit were prepared. Starting with heptakis-amino-β-CD or heptakis-amino-caproic-amide-β-CD, treated with galactosyl-glucono-amide-caproic acid, the new compounds heptakis (Gal-cap1)-CD (4) or heptakis (Gal-cap2)-CD (5) were obtained. The longer galactose spacer arm extremely favors the PNA association. The effect of branch length on K with PNA was enhanced up to 138-fold 3 as well as with DXR enhanced up to 81-fold. Hexakis (Gal-cap2)-CD (6) was prepared and the association constants with rat liver cells were observed to be 2.5 × 10¹⁰ M⁻¹. A multi-high mannose type oligosaccharide branched CD (7) showed a large association constant with DXR up to 1.1 × 10⁹ M⁻¹. The two-dimensional map for the association constants of newly synthesized oligosaccharide-branched CDs toward lectin or liver cells versus the association constants toward a drug (doxorubicin) suggested a method of finding a better targeting drug carrier. The structural effect of the oligosaccharide-CDs showed that the number and length of the branch were dominant factors in designing for enhanced dual recognition.     

Synthesis and properties of PI polyamide-SAHA conjugate

We have designed and synthesized new types of pyrrole (P)-imidazole (I) polyamide conjugates 1 and 2 possessing a suberoylanilide hydroxamic acid (SAHA) moiety that is a strong inhibitor of histone deacetylase (HDAC). SAHA conjugate 2 was designed to target the promoter region of the p16 tumor suppressor gene. The DNA binding affinity of SAHA conjugate 2 to its target sequence was examined using surface plasmon resonance. HDAC inhibition activity of conjugates 1 and 2 was evaluated using a colorimetric assay. The results demonstrated that even though it possesses the relatively large SAHA moiety, conjugate 2 has high DNA sequence-specific binding properties and moderate HDAC inhibitory activity in vitro. SAHA conjugate 2 was found to cause morphological changes in HeLa cells and to induce selective Histone H3 lysine 9 acetylation.