Carbonyl allylations by 3-halopropenes or 2-propenyl mesylate with tin(IV) chloride and tetrabutylammonium iodide

2-Propenyl tin species, prepared from 3-halopropenes or 2-propenyl mesylate with tin(IV) chloride and tetrabutylammonium iodide in dichloromethane, causes nucleophilic addition to aldehydes to produce the corresponding homoallylic alcohols.     

Hydrogel‐like elastic membrane consisting of semi‐interpenetrating polymer networks based on a phosphorylcholine polymer and a segmented polyurethane

To obtain a hydrogel‐like elastic membrane, we prepared semi‐interpenetrating polymer networks (IPNs) by the radical polymerization of methacrylates such as 2‐methacryloyloxyethyl phosphorylcholine (MPC), 2‐hydroxyethylmethacrylate, and triethyleneglycol dimethacrylate diffused into segmented polyurethane (SPU) membranes swollen with a monomer mixture. The values of Young's modulus for the hydrated semi‐IPN membranes were less than that for an SPU membrane because of higher hydration, but they were much higher than that for a hydrated MPC polymer gel (non‐SPU). According to a thermal analysis, the MPC polymer influenced the segment association of SPU. The diffusion coefficient of 8‐anilino‐1‐naphthalenesulfonic acid sodium salt from the semi‐IPN membrane could be controlled with different MPC unit concentrations in the membrane, and it was about 7 × 10² times higher than that of the SPU membrane. Fibroblast cell adhesion on the semi‐IPN membrane was effectively reduced by the MPC units. We concluded that semi‐IPNs composed of the MPC polymer and SPU may be novel polymer materials possessing attractive mechanical, diffusive‐release, and nonbiofouling properties. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 68–75, 2003     

Tris(1‐ethyl‐3‐methyl­imidazolium) hexa­chloro­lanthanate

In the title complex, (C₆H₁₁N₂)₃[LaCl₆], centrosymmetric octahedral hexa­chloro­lanthanate anions are located at the corners and face‐centers of the monoclinic unit cell. The ring H atoms of the cations interact with the Cl atoms of the anions via hydrogen bonding, and bifurcation of the hydrogen bonding is observed. Cation–cation interactions via hydrogen bonding between the ring H atoms and π‐electrons of aromatic rings are also observed as in other imidazolium salts.     

Fluorometric Determination of Trace Amounts of Fluoride Ion Using an Expanded Porphyrin

A highly selective and sensitive method of fluorometry is described for determination of the fluoride ion at the parts per billion level via the ion-pair complex formation of the fluoride ion with an expanded prophyrin [2,23-diethyl-8,17-bis(2-ethoxycarbonylethyl)-3,7,12,13,18,22-hexamethylsapphyrin (H₃sap)]. The ion-pair complex gives out an enhanced fluorescence intensity at 680 nm on excitation at 450 nm. Since the present method is based on a direct reaction of the fluoride ion with the sappyrin, a 200-fold amount of the aluminum (III) ion [10⁻⁴M (M = mol dm⁻³)] and a 2000-fold amount of the iron(III) ion (10⁻³M) over the fluoride ion did not interfere with determination of the fluoride ion at concentrations as low as 5 × 10⁻⁷M in the presence of 1,2-diaminocyclohexane-N,N,N′,N′-teraacetic acid. The proposed method was applied to determination of the fluoride ion in various water samples (tap water, river water, rain water, underground water, and hot spring water) and satisfactory results were obtained.     

Condensed thienopyrimidines. II. Synthesis and gastric antisecretory activity of thiazole and polymethylene condensed thienopyrimidine derivatives

Thiazolo[3,2-a]thieno[3,2-d]-, [3,4-d]- and [2,3-d]pyrimidin-5-one derivatives (6, 11 and 16), and polymethylene condensed thieno[3,2-d]-, [3,4-d]- and [2,3-d]pyrimidin-5-one derivatives (19-21), in which the oxygen atom of the oxazolidine moiety in 3 was replaced by a sulfur atom or methylene groups, were synthesized and evaluated for gastric antisecretory activity in pylorus-ligated rats. The structure-activity relationships of these compounds are discussed.     

Pd(0)‐catalyzed polyaddition of bifunctional vinyloxiranes with 1,3‐dicarbonyl compounds: The synthesis of polymers containing hydroxy and carbonyl groups

The palladium(0)‐catalyzed polyaddition of bifunctional vinyloxiranes [1,4‐bis(2‐vinylepoxyethyl)benzene ( 1a ) and 1,4‐bis(1‐methyl‐2‐vinylepoxyethyl)benzene ( 1b )] with 1,3‐dicarbonyl compounds [methyl acetoacetate ( 4 ), dimethyl malonate ( 6 ), and Meldrum's acid ( 8 )] was investigated under various conditions. The polyaddition of 1 with 4 was carried out in tetrahydrofuran with phosphine ligands such as PPh₃ and 1,2‐bis(diphenylphosphino)ethane (dppe). Polymers having hydroxy, ketone, and ester groups in the side groups ( 5 ) were obtained in good yields despite the kinds of ligands employed. The number‐average molecular weight value of 5b was higher than that of 5a . The polyaddition of 1b and 6 was affected by the kinds of ligands employed. The corresponding polymer 7b was not obtained when PPh₃ and 1,2‐bis(diphenylphosphino)ferrocene were used. The polyaddition was carried out with dppe as the ligand and gave polymer 7b in a good yield. The molecular weight of the polymer obtained from 1b and 8 was much higher than those of polymers 5b and 7b . The polyaddition with Pd₂(dba)₃ · CHCl₃/dppe as a catalyst (where dba is dibenzylideneacetone) produced polymer 9b in a 92% yield (number‐average molecular weight = 45,600). The stereochemistries of all the obtained polymers were confirmed as an E configuration by the coupling constant of the vinyl proton. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2487–2494, 2002     

Simultaneous determination of the binding of amantadine and its analogues to synthetic melanin by liquid chromatography after precolumn derivatization with dansyl chloride

For the determination of amantadine (1-ADA), 2-adamantanamine (2-ADA), memantine (MEM), and rimantadine (RIM) in melanin binding studies, the simultaneous determination of 1-ADA or 2-ADA, MEM, and RIM is investigated by high-performance liquid chromatographic assay with dansyl chloride as a fluorescent derivative reagent. Dansyl derivatives with fluorescent intensity are detected at an excitation wavelength of 370 nm and an emission wavelength of 506 nm. Retention times of 1-ADA, 2-ADA, MEM, and RIM derivatives are 12.2, 12.2, 15.2, and 16.6 min, respectively. The peak of 1-ADA derivative coelutes with the 2-ADA derivative. The limits of detection for 1-ADA, 2-ADA, MEM, and RIM are 0.014, 0.007, 0.012, and 0.020microM, respectively (signal-to-noise ratio of 3:1). In the intra- and interday assay, the range of standard deviation to the average of 1-ADA, 2-ADA, MEM, and RIM is 4.6-12.7%. Their recovery is also good. The ranking order for synthetic melanin binding among these compounds is RIM > MEM > 2-ADA = 1-ADA. The method is simple, sensitive, and reproducible for simultaneously measuring 1-ADA or 2-ADA, MEM, and RIM. Also, it is useful to investigate their binding kinetics to melanin.     

Radiation-induced copolymerizations of perfluorovinyl acetic acid and its methyl ester with α-olefin

Homopolymerizations and copolymerizations of perfluorovinyl acetic acid (FVA) and its methyl ester (MFVA) were carried out by γ radiation at a temperature of 25°C, a dose rate of 1 × 10⁶ rad/hr, and FVA/α-olefin and MFVA/α-olefin ratios of 10/90-90/10 in the monomer mixture. FVA and MFVA gave small quantities of brown and greasy low-molecular-weight homopolymers. The polymerization rates of both FVA and MFVA were extremely small, as shown by the maximum G value of monomer consumption of 12. FVA and MFVA reacted with α-olefin to form waxlike copolymers. The copolymerization rates of both FVA and MFVA with α-olefin were remarkably larger than those of the homopolymerizations, particularly with ethylene. The polymer compositions of FVA/ethylene or MFVA/ethylene was nearly 1/2 over a wide range of the monomer compositions. The Mayo–Lewis method gave negative r₁ (FVA) and r₁ (MFVA). The polymer composition curves could be well interpreted by introducing the penultimate model.     

Polymerizability of unsaturated monomers capable of forming stable radicals

Some unsaturated monomers bearing hindered phenol and arylamine groups capable of forming stable radicals were prepared. Radical polymerizations of vinyl monomers having such groups were investigated with the use of azobisisobutyronitrile, benzoyl peroxide, cumene hydroperoxide, and tetraethylthiuram disulfide as initiator. Polymerizations of these monomers went normally only when azobisisobutyronitrile was used as initiator. The other initiators inhibited polymerizations remarkably or completely. The results suggest that radicals resulting from benzoyl peroxide and cumene hydroperoxide or tetraethylthiuram disulfide abstract hydrogen of the phenol or the amine to produce the stable radicals, thereby inhibiting the polymerization. Meanwhile, carbon radicals resulting from azobisisobutyronitrile add selectively to the vinyl double bonds of the monomers to initiate the polymerizations. The vinyl derivatives as well as allyl derivatives and cinnamic acid derivatives copolymerize easily with conventional monomers such as styrene, maleic anhydride, and butadiene, again, only when azobisisobutyronitrile was used as initiator. Antioxidative properties for styrene copolymers and butadiene-styrene copolymers incorporating the hindered phenol monomers were investigated.     

Pre-irradiation induced grafting of styrene into crosslinked and non-crosslinked polytetrafluoroethylene films for polymer electrolyte fuel cell applications. II: Characterization of the styrene grafted films

Crosslinked and non-crosslinked polytetrafluoroethylene films (RX-PTFE and V-PTFE films, respectively) were irradiated by γ-ray and then grafted with styrene in liquid phase. Microscope FT-IR spectroscopy, TGA, solid state ¹³C CP/MAS and high resolution HS/MAS NMR spectroscopy, wide-angle X-ray diffraction (WAXD) study were used to get the structural information of the styrene grafted RX-PTFE and V-PTFE films. From microscope FT-IR spectra of the grafted RX-PTFE films, the “grafting front mechanism” was proved. TGA analysis showed that the grafted films have a small degradation step and two main degradation steps. In the ¹³C CP/MAS NMR spectra of the non-grafted films, there are no signal due to the absence of the hydrogen atom. While in the spectra of the grafted films, there are signals attributed to the polystyrene grafts. In the ¹³C HS/MAS NMR spectra of the grafted films, the relative intensity of the peaks attributed to the polystyrene grafts increased while the relative intensity of the peak attributed to PTFE matrix decreased with the increase in the DOG. From WAXD patterns, the intensity of the crystalline peak decrease with the increase in the DOG. The grafted films were sulfonated by chlorosulfonic acid and the results of highest IEC value exceeded 3.0. Those results will be reported in the near future.