Synthesis of crown ether-terminated poly(methyl methacrylate) by radical chain transfer polymerization

Mercapto-16-crown-5 was prepared starting from tetraethyleneglycol and 3-chloro-2-chloromethyl-1-propene. Radical polymerization of methyl methacrylate was carried out in the presence of mercapto-16-crown-5 as a chain transfer agent to give crown ether-terminated poly(methyl methacrylate). The end crown group was characterized by IR and ¹H-NMR spectra. Sodium cation was selectively extracted by this crown-containing polymer. The molecular weight of the obtained polymer had influence upon the ability of extraction of sodium cation.     

1,3,8,10-Tetrahydro-2,9-diazadibenzo[cd,lm]perylenes: synthesis of reduced perylene bisimide analogues

A unique family of 1,3,8,10-tetrahydro-2,9-diazadibenzo[cd,lm]perylenes (THDAP) was prepared through a new synthetic strategy. Completion of the synthesis was achieved in several steps from commercially available perylene-3,4,9,10-tetracarboxylic dianhydride via reactions between 3,4,9,10-tetra(chloromethyl)perylene and primary amines. The successful use of a variety of primary amines in the reactions indicated that the synthetic approach provides a rich opportunity to produce new functionalized perylene derivatives.     

Characterization of chemiluminescence from singlet oxygen under laminar flow conditions in a micro-channel and its quenching with beverages

Singlet oxygen was generated by reaction of sodium hypochlorite and hydrogen peroxide in a micro-channel. The two reagent solutions were delivered into the micro-channel by a syringe pump, providing a laminar flow liquid-liquid interface. The chemiluminescence from the singlet oxygen was emitted in the collapse of the interface due to molecular diffusion under laminar flow conditions. The chemiluminescence intensity was observed continuously and stably for each combination of reagents fed into the micro-channel; while, in the normal batch-type reactor the chemiluminescence peaks from singlet oxygen were observed within ca. 5 s. The features of the chemiluminescence emitted under laminar flow conditions were examined by changing the concentrations of sodium hypochlorite and hydrogen peroxide; the concentrations of 2.5 mM sodium hypochlorite and 7.5 mM hydrogen peroxide provided highest chemiluminescence intensities without bubble formation. Also, the effects of beverages, such as green tea, coffee, white wine, red wine, and sake (rice wine), on the chemiluminescence intensity as well as the concentrations of sodium hypochlorite and hydrogen peroxide were examined. The chemiluminescence intensities observed with addition of the beverages to the reagents decreased in the following orders; green tea > coffee > red wine > rice wine > white wine (being added to sodium hypochlorite); coffee > white wine > green tea > red wine > rice wine (being added to hydrogen peroxide). It was found that coffee decreased the chemiluminescence intensity (ca. 33% chemiluminescence decrease) without altering the concentrations of sodium hypochlorite or hydrogen peroxide. The cause of the decrease in chemiluminescence with coffee is discussed.     

Production of micron-sized monodispersed composite polymer particles by seeded polymerization utilizing the dynamic swelling method

 In order to develop the seeded polymerization technique utilizing the dynamic swelling method (DSM) proposed by authors for the production of micron-sized mono-dispersed “composite” polymer particles consisting of two kinds of polymers, the seeded polymerization for the dispersion of ethyl methacry-late (EMA)-swollen PS particles prepared utilizing DSM was carried out. Monodispersed PS/poly(ethyl methacrylate) (PEMA) composite particles having 7 μm in diameter were produced by the addition of NaCl to lower the solubility of EMA in medium and by the addition of CuCl₂ as a water-soluble inhibitor to depress the by-production of submicron-sized PEMA particles. Received: 16 July 1996 Accepted: 10 October 1996     

Gaseous adsorption properties of a silica-pillared layered manganese oxide

Adsorptions of N(2), H(2)O, and organic vapors including CH(2)Cl(2), CCl(4), c-C(6)H(12), C(6)H(6), n-C(6)H(14), and n-C(9)H(20) on a silica-pillared layered manganese oxide (SiHMnO) and nonane-preadsorbed SiHMnO were examined. It is found that SiHMnO has a microporosity with a wide pore width distribution showing different pore wall affinities. Micropores with smaller width preferentially accommodate the nonane preadsorbate while the surface hydrophilicity of pore wall leads to an easier detachment of the adsorbed nonane molecules. H(2)O adsorption influences both the porosity and the surface properties by accelerating a sufficient hydrolysis of the remained TEOS molecules in SiHMnO. Examinations using Dubinin-Radeshkevich (DR) equation and isosteric heat of adsorption of organic molecules provide evidences that the wall surface of micropores with smaller and larger width have less affinity toward nonpolar and polar organic vapors, respectively.     

5-Fluorouracil derivatives with serum protein binding potencies

To develop an optimal delivery system for 5-fluorouracil (5FU) using serum protein as a drug carrier, a series of its benzyl derivatives was synthesized. Then their binding to the serum protein was investigated by equilibrium dialysis. The benzyl derivatives of 5FU were strongly bound to rat plasma protein or human serum albumin. The bound percentage increased with increasing hydrophobicity. It was suggested that the benzyl derivative of 5FU existed in the blood as a complex with serum albumin and circulated for a long time as a polymeric drug does.     

The first total synthesis of (+/-)-linderol A, a tricyclic hexahydrodibenzofuran constituent of Lindera umbellata bark, with potent inhibitory activity on melanin biosynthesis of cultured B-16 melanoma cells

[reaction in text] The first total synthesis of (+/-)-linderol A, a hexahydrodibenzofuran isolated from Lindera umbellata bark, with potent inhibitory activity on melanin biosynthesis of cultured B-16 melanoma cells was achieved via a 20-step of reaction in 7.64% overall yield starting from 4,6-dimethoxysalicylaldehyde.     

Application of an Ion Beam Technique for the Design of Visible Light-Sensitive, Highly Efficient and Highly Selective Photocatalysts: Ion-Implantation and Ionized Cluster Beam Methods

As a new concept for the design of effective photocatalysts, an ion beam technology using accelerated metal ions, a metal ion implantation and an ionized cluster beam (ICB) method, have been applied to design unique photocatalysts. The metal ion implantation of TiO₂ and Ti-containing zeolites with highly accelerated metal ions (V⁺, Cr⁺, etc.) is useful in designing photocatalysts that can operate efficiently under visible light irradiation. Also, an ICB method with a low acceleration energy is useful in preparing transparent TiO₂ thin films on various types of substrates for the efficient photocatalytic degradation of pollutants diluted in water and air. The combination of the ICB method and metal ion implantation can develop the TiO₂ thin films that are able to operate not only under UV light but also under visible light irradiation.     

Novel Knöevenagel-type reaction via titanium enolate derived from Ti(O-i-Pr)4 and diketene

Knöevenagel-type reaction between diketene and aldehydes proceeded in the presence of Ti(O-i-Pr)₄. This reaction proceeded via titanium enolate derived from Ti(O-i-Pr)₄ and diketene. As for the stereoselectivity of the products, E-isomers were produced predominantly in the case of aromatic aldehydes.