Salt effect in the base-catalyzed polymerization of unsaturated amide compounds. III. Nature of the polymerization system

Coordination complexes of lithium chloride with polar solvents and monomers were isolated, and their physical properties were studied. The parallel between stabilities of isolated complexes and coordination function in the polymerization system is discussed. The increase of the Q and e values of p-vinylbenzamide (VBA) supports the mechanism of vinyl-type polymerization of VBA in the presence of the salt. The specific solvent effect of dimethyl sulfoxide was determined by measurement of electrical conductivity of a model system.     

Fluorometric determination of urea in alcoholic beverages by using an acid urease column-FIA system

An acid urease column was applied to a fluorometric flow-injection analysis (FIA) system as a recognition element for determination of urea in rice wines.

The acid urease has specific properties of showing its catalytic activity in low pH range and tolerance to ethanol in comparison to those of a urease from jack-beans. The enzymes were covalently immobilized onto porous glass beads with controlled pore size and then, packed into a small polymer column. The flow-type of the biosensing system was assembled with a sample injection valve, the immobilized enzyme column, and a flow-through quartz cell attached to a fluorescent spectrophotometer. Citrate buffer (50 mM, pH 5.0) as the carrier solution was continuously pumped through the system. Sample solutions were introduced into the system via a rotary injection valve. A standard urea solution was measured through monitoring variations in fluorescent intensity attributable to fluorescent isoindole derivatives formed by coupling with ammonia molecules released in the enzymatic hydrolysis of urea and orthophthalaldehyde reagents. The fluorescent intensity was measured under the conditions of λ_ex = 415 nm and λ_em = 485 nm. A wide, linear relationship was obtained between the concentration of urea (1.0–100 μM) and the variation in fluorescent intensity. The monitoring did not suffer from ethanol and various amino acids contained in rice wines. Real samples pretreated with ion exchange resins for removal of endogenous ammonia were introduced into the FIA system and urea in the samples was determined. These results were compared with those obtained with use of an F-kit method. The proposed FIA system should present sensitive, selective and convenient analysis of urea in alcoholic beverages.     

A novel synthesis of 1H-pyrrole-2,3,4,5-tetracarboxylates

A novel and convenient synthesis of 1H -pyrrole-2,3,4,5-tetracarboxylates is described. Photocyclization of 1,1′-bis(methoxycarbonyl)divinylamine with acetylenedicarboxylates gave 7-azabicyclo[2.2.1]hept-2-ene-1,2,3,4-tetracarboxylates 2a-i , which on melting split ethylene off to yield 1H-pyrrole-2,3,4,5-tetracarboxylates 3a-i quantitatively.     

Photocatalytic Organic Syntheses: Selective Cyclization of Amino Acids in Aqueous Suspensions

Photocatalytic reactions occurring at semiconductor particles/solution interfaces can be applied to organic syntheses. In this review article, examples of photocatalytic syntheses of cyclic amino acids by suspended semiconductor particles, e.g., titanium(IV) oxide or cadmium(II) sulfide are introduced and interpreted. Different from the photocatalytic decomposition of pollutants under aerobic conditions, selective conversion of organic compounds can be driven by the photocatalytic reactions under deaerated conditions.     

Cationic copolymerization of indene with styrene derivatives: Synthesis of random copolymers of indene with high molecular weight

Random copolymers with high molecular weights of indene and p‐methylstyrene (pMeSt) were synthesized by cationic polymerization with trichloroacetic acid/tin tetrachloride in CH₂Cl₂ at low temperatures. When indene and pMeSt (1:1 v/v), for example, were polymerized at ?40 °C, both monomers were consumed at very similar rates to give a copolymer with high molecular weight [number‐average molecular weight (M_n): 8–9 × 10⁴]. This is indeed quite unexpected behavior for the combination of these two monomers because pMeSt polymerized over 1000 times faster than indene in the homopolymerization under the reaction conditions previously described. The product copolymer of indene and pMeSt had a random monomer sequence in it that was confirmed by NMR analyses and thermal‐property measurements. In sharp contrast with pMeSt, styrene and p‐chlorostyrene, which have no electron‐donating groups on the phenyl ring, led to low molecular weight polymers (M_n < 10,000) in the copolymerization with indene (1:1 v/v). © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2449–2457, 2002     

Acid-catalyzed reaction of pyrazolo[1,5-a]pyridines with aldehydes: Formation of bis(pyrazolo[1,5-a]pyrid-3-yl)methane

Reaction of pyrazolo[1,5-a]pyridines with aldehydes in the presence of trifluoroacetic acid gave bis[pyrazolo[1,5-a]pyrid-3-yl)methanes in high yields.     

Palladium-catalyzed regio- and diastereo-selective allylic alkylation using 2-(diphenylphosphino)benzoic acid: construction of vicinal quaternary and tertiary carbon centers

The palladium-catalyzed regio- and diastereo-selective allylic alkylation of allyl acetates with carbon nucleophiles occurred. The stereochemistry was highly controlled by the palladium catalyst with 2-(diphenylphosphino)benzoic acid as the ligand, and vicinal quaternary and tertiary carbon centers were constructed.     

Polymeric phosphonium salts as a novel class of cationic biocides. V. Synthesis and antibacterial activity of polyesters releasing phosphonium biocides

Polyesters were prepared which retained phosphonium biocides as counter ions of sodium sulfonate moieties incorporated into the polymers, and surface antibacterial activity of the polyester films against Staphylococcus aureus and Escherichia coli was explored. These films exhibited a high surface antibacterial activity against S. aureus and E. coli, particularly against S. aureus, and the activity was affected by the structure and the compositional ratio of the phosphonium salts. Amount of the released phosphonium salts was very small, so that liberation of the phosphonium biocides can be expected to occur over a long period. Morphological changes of the cells of S. aureus and E. coli in contact with the polyester films were evaluated by scanning electron microscopy. It was found that the surface antibacterial activity of the polyester films was rather bacteriostatic than bactericidal as evidenced by no morphological changes of the bacterial cells in contact with the phosphonium biocides © 1993 John Wiley & Sons, Inc.     

Some structural features induced by the space-time metrical fluctuation in the theory of gravitational fields

Under the assumption that the so-called space-time fluctuationy(x) in a classical sense, attached to each point of the gravitational field at some microscopic stage, is summarized as the metrical fluctuation in the formg _λκ (x)=g_λκ (x)·exp2σ(y(x)), some new physical aspects induced by the conformal scalarσ(x) (≡σ(y(x))) are found: By introducing the torsionT _κ ^λμ (x) from a general standpoint, the resulting micro-gravitational field is made to have a conformally non-Riemannian structure, where a special form ofT _κ ^λμ (i.e.,T _κ ^λμ =δ _κ ^λ σ_μ?δ _κ ^μ σ_λ(σ_μ=?σ/?x ^μ)) shows some peculiar features. An averaging process with respect toy is taken into account, by which the spatial structure of the corresponding macro-field is shown, in general, to have a somewhat “non”-Riemannian structure due to the contributions of the torsionT _κ ^λμ .     

The circular dichroism spectra of the β-cyclodextrin complex with azulene

When azulene is included in the cavity of β-cyclodextrin (β-CDx), induced circular dichroism (CD) bands are observed in the corresponding absorption bands of azulene. On the basis of the theoretical conclusions for β-CDx complexes with naphthalene derivatives of Harata and Uedaira, it is concluded from the signs of the CD bands that the first (about 455 to 715 nm), third (about 290 to 305 nm) and fifth (at about 238 nm) absorption bands have the transition dipole moments perpendicular to the long axis and the second 305 to 360 nm), fourth (about 240 to 290 nm) and sixth (shorter than 220 nm) absorption bands have the transition dipole moments parallel to the long axis of azulene. Our assignments are in complete agreement with earlier assignments. Our experimental results do not provide any information regarding two new electronic transitions suggested theoretically by Thulstrup et al.