Ruthenium-catalyzed arylation of 2-alkenylpyridines with aryl bromides: alternative E,Z-selectivity to Mizoroki-Heck reaction

Regio- and stereoselective arylation of 2-alkenylpyridines with aryl bromides is catalyzed by specific Ru(II)-phosphine complexes affording beta-arylated (Z)-2-alkenylpyridines, in which the aryl moiety is introduced cis to the pyridyl group. This geometrical selectivity is in sharp contrast to the Mizoroki-Heck reaction. [reaction: see text]     

Structures and cytotoxic properties of sponge-derived bisannulated acridines

A reinvestigation of sponge natural products from additional Indo-Pacific collections of Xestospongiacf. carbonaria and X. cf. exigua has provided further insights on the structures, biological activities, and biosynthetic origin of bisannulated acridines. These alkaloids include one known pyridoacridine, neoamphimedine (2), and three new analogues, 5-methoxyneoamphimedine (4), neoamphimedine Y (5), and neoamphimedine Z (6). A completely new acridine, alpkinidine (7), was also isolated. A disk diffusion soft agar assay, using a panel of five cancer cell lines (solid tumors and leukemias) and two normal cells, was used to evaluate the differential cytotoxicity (solid tumor selectivity) of the sponge semipure extracts and selected compounds including amphimedine (1), 2, 4, and 7. While all four compounds were solid tumor selective, 1 and 2 were the most potent and 4 was the most selective. The rationale used to characterize the new structures is outlined along with the related biosynthetic pathways envisioned to generate 2 and 7.     

Development of a regenerable cell culture system that senses and releases dead cells

We developed a rapidly regenerable cell culture system in which the cell culture substrate detects cell death and selectively releases the dead cells. This culture material was achieved by combining a detector that responds to the signal from the dead cells and an actuator to release the dead cells. Benzo-18-crown-6-acrylamide (BCAm) with a pendant crown ether receptor was used as the sensor to recognize cellular signals and N-isopropylacrylamide (NIPAM) was used as the actuator. This copolymer of NIPAM and BCAm can respond to potassium ions and change its nature from hydrophobic to hydrophilic at the culture temperature of 37 degrees C. Living cells concentrate potassium ion internally; when cells die, potassium ions are released. The polymer surface recognizes the potassium ions released from the dead cells, the NIPAM hydrates, and the dead cells are selectively detached. This in vitro culture system is a novel one in which artificial culture materials work cooperatively with cellular metabolism by responding to this signal from the cells, thereby realizing in vitro tissue regeneration partly mimicking the mechanisms of in vivo homeostasis.     

The Biological Effects of Forsythia Leaves Containing the Cyclic AMP Phosphodiesterase 4 Inhibitor Phillyrin

Forsythia fruit (Forsythia suspensa Vahl (Oleaceae)) is a common component of Kampo medicines for treating the common cold, influenza, and allergies. The main polyphenolic compounds in the leaves of F. suspensa are pinoresinol β-d-glucoside, phillyrin and forsythiaside, and their levels are higher in the leaves of the plant than in the fruit. It is known that polyphenolic compounds stimulate lipid catabolism in the liver and suppress dyslipidemia, thereby attenuating diet-induced obesity and polyphenolic anti-oxidants might attenuate obesity in animals consuming high-fat diets. Recently, phillyrin was reported as a novel cyclic AMP phosphodiesterase 4 (PDE4) inhibitor derived from forsythia fruit. It was expected that the leaves of F. suspensa might display anti-obesity effects and serve as a health food material. In this review, we summarized our studies on the biological effects of forsythia leaves containing phillyrin and other polyphenolic compounds, particularly against obesity, atopic dermatitis, and influenza A virus infection, and its potential as a phytoestrogen.     

Automated system for simultaneous analysis of delta(13)C, delta(18)O and CO(2) concentrations in small air samples

In this paper we present an automated system for simultaneous measurement of CO(2) concentration, delta(13)C and delta(18)O from small (<1 mL) air samples in a short period of time (approximately 1 hour). This system combines continuous-flow isotope ratio mass spectrometry (CF-IRMS) and gas chromatography (GC) with an inlet system similar to conventional dual-inlet methods permitting several measurement cycles of standard and sample air. Analogous to the dual-inlet method, the precision of this system increases with the number of replicate cycles measured. The standard error of the mean for a measurement with this system is 0.7 ppm for the CO(2) concentration and 0.05 per thousand for the delta(13)C and delta(18)O with four replicate cycles and 0.4 ppm and 0.03 per thousand respectively with nine replicate cycles. The mean offset of our measurements from NOAA/CMDL analyzed air samples was 0.08 ppm for the CO(2) concentration, 0.01 per thousand for delta(13)C and 0.00 per thousand for delta(18)O. A specific list of the parts and operation of the system is detailed as well as some of the applications for micrometeorological and ecophysiological applications.     

Rapid separation of pharmaceutical enantiomers using electrokinetic chromatography with a novel chiral microemulsion

A novel oil-in-water microemulsion incorporating the chiral surfactant dodecoxycarbonylvaline (DDCV) was used to achieve the rapid enantiomeric separation of pharmaceutical drugs by electrokinetic chromatography (EKC). Incorporation of DDCV into a microemulsion resulted in an elution range more than double that provided the micellar form of the surfactant aggregate. Interestingly, for the same compounds the enantioselectivity provided by the chiral DDCV microemulsions ranged from 1.06-1.30 for the neutral and cationic drugs, which was slightly higher than that provided by chiral DDCV micelles. The use of a low surface tension oil (ethyl acetate) permitted a much lower concentration of chiral surfactant to be employed; this, together with the use of a zwitterionic buffer (ACES) resulted in a very low conductivity microemulsion that allowed a higher separation voltage to be utilized, resulting in rapid enantiomeric separations (< 8 min.). Mobility matching of the buffer cation(s) was used to improve peak shape and efficiencies. In our limited survey of the phase diagram, the optimum composition of the microemulsion buffer was 1.0% (w/v) DDCV (30 mM), 0.5% (v/v) ethyl acetate, 1.2% (v/v) 1-butanol and 50 mM ACES buffer at pH 7.     

Spin—rotational relaxation study of molecular reorientation in the presence of internal extended rotational diffusion

Molecular reorientation in the presence of internal rotation is investigated and an analytical expression for the spin—rotational rate of a nucleus attached to the internal rotor is obtained in terms of the internal angular-momentum correlation time. A model of a symmetric-top molecule undergoing anisotropic rotational diffusion is extended to include a modified extended diffusion of internal rotation. The result is applied to liquid toluene and the internal angular-momentum correlation time is evaluated from the ¹³C nuclear spin—rotational relaxation rate of the methyl carbon. A comparison with the previous result on the dipole—dipole relaxation data is made and the consistency of the present theory is discussed.     

Template-directed self-assembly of 10-microm-sized hexagonal plates

This article presents a strategy for the fabrication of ordered microstructures using concepts of design inspired by molecular self-assembly and template-directed synthesis. The self-assembling components are 4-microm-thick hexagonal metal plates having sides 10 microm in length ("hexagons"), and each template consists of a 4-microm-thick circular metal plate surrounding a central cavity, the perimeter of which is complementary in shape to the external edges of a two-dimensional, close-packed array of hexagons. The hexagons and templates (collectively, "pieces") were fabricated via standard procedures and patterned into hydrophobic and hydrophilic regions using self-assembled monolayers (SAMs). Templated self-assembly occurs in water through capillary interactions between thin films of a nonpolar liquid adhesive coating the hydrophobic faces of the pieces. The hexagons tile the cavities enclosed by the templates, and the boundaries of the cavities determine the sizes and shapes of the assemblies. Curing the adhesive with ultraviolet light furnishes mechanically stable arrays having well-defined morphologies. By allowing control over the structures of the resulting aggregates, this work represents a step toward the development of practical methods for microfabrication based on self-assembly.     

Development of a new file search system for nuclear magnetic resonance spectra: Production of an Enlarged Data Base and Search Test

A practical search system for proton n.m.r. spectra is reported. The coding rules and search algorithms are described in detail. Data for 8000 spectra have been converted into a computer-readable file from printed charts. Several search tests are used to evaluate the usefulness of the search system, and various effects of experimental conditions such as different instruments, frequencies and solvents on recall efficiency are described. The results presented indicate that the system should be applicable to routine analytical work.