Facile deposition of [60]fullerene and carbon nanotubes on ITO electrode by electrochemical oxidative polymerization of ethylenedioxythiophene

It was found that [60]fullerene encapsulated in p-sulfonatocalix[8]arene and single-walled carbon nanotubes (SWNTs) solubilized by sodium dodecylsulfate can be readily deposited on the ITO electrode by electrochemical oxidative polymerization of ethylenedioxythiophene (EDOT) without chemical modification of these carbon clusters. The driving force for the deposition is an electrostatic interaction between the anionic complexes and the cationic charges of poly(EDOT) formed in the oxidative polymerization process. The surface morphology was thoroughly characterized by scanning electron micrograph: the [60]fullerene/poly(EDOT) film is covered by nano-particles with 20-100 nm diameters whereas the SWNTs/poly(EDOT) film is covered by nanorods with several microm length and ca. 100 nm diameter. The results indicate that the anionic complexes act as nuclei for the polymer growth in the oxidation polymerization. Interestingly, when these modified ITO electrodes were photoirradiated, the appearance of a photocurrent wave was observed. The action spectra showed that the photoexcited energy of [60]fullerene or SWNTs is efficiently collected by the electroconductive poly(EDOT) film and transferred to the ITO electrode.     

Synthesis of methylpyridine derivatives. XXXV. Reaction of acetylpyridine with phosphoryl chloride to give alkynylpyridine

Reaction of 3-acetyl-4,6-dimethyl-2-(1H)pyridone ( 9a ) with phosphoryl chloride gives 2-chloro-3-ethynyl-4,6-dimethylpyridine ( 10a ). 3-Acetyl-4-hydroxy-6-methyl-2(1H)pyridone (14a) and 3-acetyl-2,6-dimethyl-4-(1H)-pyridone (21) undergoes similar reaction to give the corresponding ethynyl (16 and 23) and chlorovinyl (15 and 22) pyridines, respectively. The chlorination of 3-acetylpyridine and pyrimidine derivatives is further described.     

Model Construction for the A–B–C Ring System of Lysergic Acid via Vilsmeier–Haack‐Type Cyclization of 1H‐Indole‐4‐propanoic Acid Derivatives

Vilsmeier–Haack‐type cyclization of 1H‐indole‐4‐propanoic acid derivatives was examined as model construction for the A–B–C ring system of lysergic acid ( 1 ). Smooth cyclization from the 4 position of 1H‐indole to the 3 position was achieved by Vilsmeier–Haack reaction in the presence of K₂CO₃ in MeCN, and the best substrate was found to be the N,N‐dimethylcarboxamide 9 (Table 1). The modified method can be successfully applied to an α‐amino acid derivative protected with an N‐acetyl function, i.e., to 27 (Table 2); however, loss of optical purity was observed in the cyclization when a chiral substrate (S)‐ 27 was used (Scheme 5). On the other hand, the intramolecular Pummerer reaction of the corresponding sulfoxide 20 afforded an S‐containing tricyclic system 22 , which was formed by a cyclization to the 5 position (Scheme 3).     

Arg-72 of pharaonis phoborhodopsin (sensory rhodopsin II) is important for the maintenance of the protein structure in the solubilized states

In bacteriorhodopsin (bR), Arg-82bR has been proven to be a very important residue for functional role of this light-driven proton pump. The arginine residue at this position is a super-conserved residue among archaeal rhodopsins. pharaonis phoborhodopsin (ppR; or called as "pharaonis sensory rhodopsin II") has its absorption maximum at 498 nm and acts as a sensor in the membrane of Natronobacterium pharaonis, mediating the negative phototaxis from the light of wavelength shorter than 520 nm. To investigate the role of the arginine residue (Arg-72ppR) of ppR corresponding to Arg-82bR, mutants whose Arg-72ppR was replaced by alanine (R72A), lysine (R72K), glutamine (R72Q) and serine (R72S) were prepared. These mutants were unstable in low concentrations of NaCl and lost their color gradually when the proteins were solubilized with 0.1% n-dodecyl-beta-D-maltoside. The order of instability was R72S > R72A > R72K > R72Q > the wild type. The rates of denaturation were reduced in a solution of high concentrations of monovalent anions.     

Nigellamines A3, A4, A5, and C, new dolabellane-type diterpene alkaloids, with lipid metabolism-promoting activities from the Egyptian medicinal food black cumin

New dolabellane-type diterpene alkaloids, nigellamines A(3), A(4), A(5), and C, were isolated from the methanolic extract of an Egyptian medicinal food, black cumin (the seeds of Nigella sativa). Their absolute configurations were determined on the basis of chemical and physicochemical evidence. Nigellamines were found to lower triglyceride levels in primary cultured mouse hepatocytes, and in particular, the activity of nigellamine A(5) was equivalent to that of the hypolipidemic agent, clofibrate.     

Diarylurea-linked zinc porphyrin dimer as a dual-mode artificial receptor: supramolecular control of complexation-facilitated photoinduced electron transfer

A novel porphyrinic receptor 1 in which two zinc porphyrins are bridged by two diarylurea linkers was developed for recognition of a viologen derivative (hexyl viologen, HV). The electronic absorption spectra as well as the 1H NMR experiments revealed that the HV molecule was bound to the cleft in 1 mainly through carbonyl dipole-charge interactions to afford a 1:1 complex. From the steady-state fluorescence spectroscopic study, the photoinduced electron transfer (PET) from 1 to HV was extremely facilitated by the receptor-substrate complexation. The receptor 1 also formed a 1:1 complex with 1,4-diazabicyclo[2.2.2]octane (DABCO) through two Zn-N coordination interactions, and, using DABCO as an inhibitor, we suppressed the PET reaction via the substrate exchange.     

Quantitative estimation of NH3 partial pressure in H2 desorbed from the Li-N-H system by Raman spectroscopy

The partial pressure of NH3 gas estimated by Raman spectroscopy indicates that approximately 0.1% NH3 inevitably contaminates the H2 desorbed from a hydrogen storage material composed of LiH and LiNH2 at any temperature up to 400 degrees C in a closed system.     

Isolation of heptadepsin, a novel bacterial cyclic depsipeptide that inhibits lipopolysaccharide activity

Lipopolysaccharide (LPS) is considered to cause various inflammatory reactions. We searched among microbial secondary metabolites for compounds that could inhibit LPS-stimulated adhesion between human umbilical vein endothelial cells (HUVEC) and human myelocytic cell line HL-60 cells. In the course of our screening, we isolated a novel cyclic depsipeptide, which we named heptadepsin, from the whole culture broth of Paenibacillus sp. The addition of heptadepsin prior to LPS stimulation decreased HL-60 cell-HUVEC adhesion without showing any cytotoxicity. It also inhibited the cellular adhesion induced by lipid A, the active component of LPS, but it did not inhibit TNF-alpha or IL-1beta-induced cell adhesion. The result of surface plasmon resonance (SPR) analysis revealed that heptadepsin interacted with lipid A directly. Thus, heptadepsin, a novel naturally occurring cyclic heptadepsipeptide, was shown to inactivate LPS by direct interaction with LPS.