Novel neuronal nitric oxide synthase (nNOS) selective inhibitor, aplysinopsin-type indole alkaloid, from marine sponge Hyrtios erecta

Two novel aplysinopsin-type indole alkaloids, 1 and 2, and three known indole alkaloids were isolated from the marine sponge Hyrtios erecta. These compounds exhibited selective inhibitory activity against the neuronal isozyme of nitric oxide synthase (nNOS). Furthermore, new quinolone 7 was also isolated from the same marine sponge. The chemical structures of these new compounds were elucidated on the basis of spectroscopic analysis.     

An investigation on a broad infrared band with the maximum at approximately 1300 cm(-1) in magnesia cement,phase 3

In magnesia cement, phase 3, a broad and strong infrared band was observed with the maximum at approximately 1300 and 1050 cm(-1) in the H and D systems, respectively. To clarify the origin of the 1300 cm(-1) band the temperature dependency of the infrared spectra of the H system was observed and the spectra analyzed on the basis of a strong vibrational coupling of the OH stretching with lattice modes. The fitting was quite well, giving rise to the origin of the 1300 cm(-1) band of the OH stretching.     

High-performance liquid chromatographic determination of (S)-(-)-ofloxacin and its metabolites in serum and urine using a solid-phase clean-up

A sensitive and selective method for the simultaneous determination of (S)-(-)-ofloxacin [(S)-(-)-OFLX] and its metabolites in serum and urine was developed using isocratic high-performance liquid chromatography with a specific solid-phase extraction procedure. (S)-(-)-OFLX and its metabolites, desmethyl-(S)-(-)-OFLX and (S)-(-)-OFLX N-oxide, were eluted from a C8 solid-phase column with recoveries of more than 98%. These compounds were separated and determined by means of a reversed-phase column with fluorimetric detection. Validation studies showed that the results were linear for (S)-(-)-OFLX in serum over the range 10-1200 ng/ml and in urine over the range 1-200 micrograms/ml. Analysis for (S)-(-)-OFLX and its metabolites showed good precision and accuracy with a relative standard deviation of less than 6%.     

Catalytic enantioselective alkenylation and phenylation of trifluoromethyl ketones

Catalytic enantioselective alkenylation and phenylation of trifluoromethyl ketones are described. High enantioselectivity (up to 84% ee) was produced in an alkenylation of aryl trifluoromethyl ketones using a CuF-DTBM-SEGPHOS complex as the catalyst (5-10 mol %) and alkenylsilanes as the nucleophile. This is the first example of catalytic enantioselective alkenylation of trifluoromethyl ketones. The products are versatile chiral building blocks, which contain a trifluoromethyl-substituted tertiary alcohol moiety.     

Aerobic oxidation of 1,3,5-triisopropylbenzene using N-hydroxyphthalimide (NHPI) as key catalyst

The first systematic study on the aerobic oxidation of 1,3,5-triisopropylbenzene was examined by the use of N-hydroxyphthalimide (NHPI) as a key catalyst. It was found that 1,3,5-triisopropylbenzene was efficiently oxidized with O₂ in the presence of a catalytic amount of NHPI and azobisisobutyronitrile (AIBN) at 75 °C. Upon treatment of the resulting products with sulfuric acid followed by acetic anhydride led to 5-acetoxy-1,3-diisopropylbenzene and 3,5-diacetoxy-1-isopropylbenzene as major products and a small amount of 1,3,5-triacetoxybenzene. When t-butylperoxypivalate (BPP) was employed as a radical initiator, the oxidation could be achieved in good yield even at 50 °C. This oxidation provides a facile method for preparing phenol derivatives bearing an isopropyl moiety, which can be used as pharmaceutical starting materials.     

Molecular metamagnet [Ni(4ImNNH)(2)(NO(3))(2)] (4ImNNH = 4-imidazolyl nitronyl nitroxide) and the related compounds showing supramolecular H-bonding interactions

A new chelating radical ligand 4ImNNH (2-(4-imidazolyl)-4,4,5,5-tetramethylimidazolin-1-oxyl 3-oxide) was prepared, and complexation with divalent transition metal salts gave complexes, [M(4ImNNH)(2)X(2)], which showed intermolecular ferromagnetic interaction in high probability (7 out of 10 paramagnetic compounds investigated here). The nitrate complexes (X = NO(3); M = Mn (1), Co (2), Ni (3), Cu (4)) crystallize isomorphously in monoclinic space group P2(1)/a. The equatorial positions are occupied with two 4ImNNH chelates and the nitrate oxygen atoms are located at the axial positions. Magnetic measurements revealed that the intramolecular exchange couplings in 1, 2, and 4 were antiferromagnetic, while that in 3 was ferromagnetic with 2J/k(B) = +85 K, where the spin Hamiltonian is defined as H = -2J(S(1).S(2) + S(2).S(3)) based on the molecular structures determined as the linear radical-metal-radical triads. The intramolecular ferromagnetic interaction in 3 is interpreted in terms of orthogonality between the radical pi and metal dsigma orbitals. Compounds 1-3 exhibited intermolecular ferromagnetic interaction ascribable to a two-dimensional hydrogen bond network parallel to the crystallographic ab plane. Complex 3 became an antiferromagnet below 3.4 K and exhibited a metamagnetic transition on applying a magnetic field of 5.5 kOe at 1.8 K. The complexes prepared from metal halides, [M(4ImNNH)(2)X(2)] (X = Cl, Br; M = Mn, Co, Ni, Cu), showed intramolecular antiferromagnetic interactions, which are successfully analyzed based on the radical-metal-radical system. The crystal structures determined here on 1-4, [Mn(4ImNNH)(2)Cl(2)], and [Cu(4ImNNH)(2)Br(2)] always have intermolecular hydrogen bonds of H(imidazole).X(axial ligand)-M, where X = NO(3), Cl, Br. This interaction seems to play an important role in molecular packing and presumably also in magnetic coupling.     

Epoxyquinol A, a highly functionalized pentaketide dimer with antiangiogenic activity isolated from fungal metabolites

A unique pentaketide dimer structure of a novel fungal metabolite with antiangiogenic activity, designated as epoxyquinol A (1), was determined on the basis of NMR spectral data as well as the X-ray crystallographic analysis. 1 inhibits the endothelial migration induced by vascular endothelial growth factor (ED100 = 3 mug/mL).     

Fabrication of polymer Langmuir-Blodgett films containing regioregular poly(3-hexylthiophene) for application to field-effect transistor

Semiconducting thin films consisting of regioregular poly(3-hexylthiophene) (RR-PHT) and poly(N-dodecylacrylamide) (pDDA) were constructed by the Langmuir-Blodgett (LB) technique. A mixture of RR-PHT and pDDA spread from a chloroform solution on a water surface forms a stable monolayer, which can be transferred onto solid substrates by the LB method, yielding a well-defined polymer LB film. Surface morphology studies of the LB film indicate that the RR-PHT is dispersed uniformly throughout the surface. The polymer thin film was chemically doped by contacting with FeCl3 acetonitrile solution, and a conductivity of 5.6 S/cm was achieved. Further, the LB film was utilized as the semiconducting film in the field-effect transistor (FET), and mobilities of 2.2 x 10(-4) and 4.4 x 10(-4) cm2 V(-1) s(-1) were obtained by analyzing the saturated and linear regions of the current-voltage characteristic, respectively.     

High-molecular-weight poly(p-phenyleneterephthalamide) by the direct polycondensation reaction with triphenyl phosphite

Poly(p-phenyleneterephthalamide) of high molecular weight was obtained when the polycondensation of terephthalic acid and p-phenylenediamine was carried out in N-methylpyrrolidone (NMP) that contained dissolved CaCl₂ and LiCl in the presence of pyridine. The molecular weight of the polymer obtained varied with the amount of pyridine relative to the metal salts and with the molar ratios of CaCl₂ to LiCl, the maximum η_inh value of 4.5 being obtained under the conditions Py/(CaCl₂ + LiCl) ≈ 2.5 (mol/mol), CaCl₂/LiCl ≈ 1.2 (mol/mol), and LiCl + CaCl₂ ≈ 4 g. Among the solvents tested, NMP was significantly effective for the reaction. Polycondensations of several combinations of other dicarboxylic acids and diamines were carried out with limited success.