Resolution of lymphocyte subpopulations derived from rat spleen by polyamine-graft-PHEMA copolymer

The retention behavior of lymphocyte subpopulations, B cell, T cell and null cell, derived from rat spleen to polyamine-graft-poly(2-hydroxyethyl methacrylate) copolymer (HA) surface was investigated, focusing on the conformational transition of the polyamine side chain as well as the protonation of amino groups in the polyamine grafts. Furthermore, the availability of HA was discussed as a column adsorbent for separation of lymphocyte subpopulations derived from spleen. The conformational transition of polyamine grafts significantly influenced the mode of retention of lymphocyte subpopulations. When polyamine grafts existed in an aggregated conformation (protonatin degree α < 0.5), the retention of lymphocyte subpopulations was decreased in the order B cell> null cell> T cell. On the other hand, when polyamine existed in an extended conformation into the aqueous interior from the matrix interface (α > 0.5), T cell retention became greater than null cell retention, resulting in a decreased B cell> T cell> null cell order. These results indicate that the differential retention of spleen lymphocyte subpopulations is attributed to their differential responses to the change in matrix interface accompanied by the protonation of amino groups. Furthermore, spleen lymphocytes were compared with lymph node lymphocytes in terms of resolution efficacy by an HA copolymer column.     

Elucidation of solid-state complexation in ground mixtures of cholic acid and guest compounds

The solid-state complexation between cholic acid (CA) and either methyl p-hydroxybenzoate (MPB) or ibuprofen (IBP) was investigated. Powder X-ray diffractometry, IR spectroscopy and thermal analysis suggested the complex formation between CA and MPB as well as between CA and IBP by co-grinding method. The stoichiometry of CA-MPB was 1 : 1 while that of CA-IBP was 2 : 1, reflecting the effect of guest size on complex formation. The guest compounds were assumed to be included in the channel of complexes formed by hydrogen bonds among CA molecules.     

Enantioselective ester synthesis in the presence of optically active polymers

Enantiomer-differentiating ester syntheses from acid salts, chlorides, and an anhydride were studied in the presence of optically active polyamines. Enantiomer selection occurred in reactions of a racemic salt with an achiral alkyl bromide and vice versa, which is good evidence of the importance of activation of the carboxylate group by complexation of the counterion and activation of alkyl bromide by the formation of a quaternary salt with polyamine under solid–liquid, phase-transfer reaction conditions. Only small optical activity was observed in the products of acid anhydride or chloride with alcohol.     

1,2,4-Triazines, 9. The synthesis of novel 4-amino-1,6-dihydro-1,2,4-triazinones

3-Alkylthio-4-amino-1,6-dihydro-1,2,4-triazin-5(4H)-ones were synthesized by the reduction of 3-thio-4-amino-1,2,4-triazine-3,5(2.H,4H)-diones and successive S-alkylation. The regiospecific alkylation on the N-1 position or the exo amino group leads to a variety of 1,6-dihydro-1,2,4-triazin-5(4H)-one derivatives. An alternative synthesis of 3-thio-4-amino-1,6-dihydro-1,2,4-triazine-3,5(2H,4H)-diones was accomplished through the cyclization of 1-thiocarbohydrazidoacetamide derivatives.     

Synthesis of (S-(−)-wybutine,the fluorescent minor base from yeast phenylalanine transfer ribonucleic acids

The Wittig reaction of 1-benzyl-7-formylwye (12) with (R)-[2-carboxy-2-[(methoxycarbonyl)amino]ethyl]triphenylphosphonium chloride (8) followed by successive methylation and reduction gave (-)-wybutine [(S)-1a].     

Photochemical Ionic-Conductivity Switching Systems of Photochromic Crown Ethers for Information Technology

Design of two types of ion-conducting systems using photochromic crown ethers as the photocontrol agents is described; one type is based on the phase transition of azobenzene derivatives induced by their photoisomerization and the other based on the molecular control of metal ion complexation by crowned spirobenzopyrans. The photoresponsive ion-conducting systems are applicable to electrostatic imaging and photorefractive materials.     

The second-generation synthesis of BICMAP analogues

We previously reported the synthesis of BICMAP (1a) via 6-diphenylphosphino-2,3-dihydrobenzofuran as a key intermediate. However, we did not successfully synthesize BICMAP analogues via a similar synthetic route. Herein we report the second-generation synthesis of BICMAP and its derivatives via diethylphosphonate as a key intermediate.     

Recent Advances in Self‐Oscillating Polymer Material Systems

In 1996, we first reported self‐oscillating polymer gels exhibiting autonomous swelling‐deswelling oscillations driven by the Belousov‐Zhabotinsky reaction. In contrast to conventional stimuli‐responsive gels, the self‐oscillating gel can autonomously and periodically change its volume in a closed solution without any external stimuli. Since the first report, the novel concept of self‐oscillating gels has been expanded into various polymer and gel systems. Herein, we summarize recent advances in self‐oscillating polymers and gels.