Novel ring transformation of quinolines to indole derivatives in two steps via 1,4-dihydroquinoline derivatives

Diphenyl 1-phenoxycarbonyl-1,4-dihydroquinoline-4-phosphonates 5c-g, obtained from the reaction of corresponding quinoline derivatives 1 with phenyl chloroformate and triphenyl phosphite in one step, were ozonized in CHCl₃ and CH₃COOH. Treatment of the resulting mixture with NaHCO₃ produced the 3-formyl-1-phenoxycarbonylindole derivatives 8a-e in high yields. The ring transformation of quinolines 1 to indoles 8 proceeds under mild conditions.     

Chemical effects in high-resolution nickel Kalpha X-ray fluorescence spectra.

The nickel Kalpha spectra of oxides, halides (NiF2, K2NiF6, NiCl2, NiBr2), complex compounds, and metal are measured with two different double-crystal X-ray fluorescence spectrometers. The peak shifts and line width changes due to the changes in the chemical states are reported. High reproducibility has been shown for the chemical shift and line width measurements. The DV-Xalpha molecular orbital calculation at the ground and the 1s(-1) hole states was performed to prove that the chemical effect originats from the charge-transfer mechanism.     

Persistence of Si(111)7 × 7 surface structure under air exposure

Changes in Si(111) 7 × 7 pattern with air exposure are studied by RHEED. The relation between exposure time and air-oxidized film thickness is obtained using an ellipsometer. As a result, it is found that the 7 × 7 surface after air exposure (760 Torr, 20 h) still exhibits several 7 × 7 spots near normal ones in the RHEED pattern. The air-oxidized film thickness corresponding to this exposure is about 13 Å. The fact that the 7 × 7 spots do not disappear with HF etching of the oxide film indicates that the superstructure remains not at the oxide surface but at the substrate selvedge. The 7 × 7 spots gradually disappear after longer exposure time and no 7 × 7 spots can be observed after 40 h (about 15 Å in oxide thickness). For a sample exposed longer than 40 h, no 7 × 7 spots reappear, even if the oxide is removed by HF. Therefore, it is concluded that the structure of the substrate selvedge changes with exposure time.     

Development of high resolution resonance ionization mass spectrometry for trace analysis of 93mNb

⁹³Nb(n, n′)^93mNb reaction allows retrospective estimation of integrated fast neutron dose in nuclear reactor. We proposed isomer-selective trace analysis of ^93mNb by Resonance Ionization Mass Spectrometry (RIMS) combined with a gas-jet atomic source and an injection locked Ti:Sapphire laser system operated at several kHz. Resonant ionization spectroscopy of Nb in gas-jet using Ti:Sapphire laser was demonstrated.     

The preparation of 1,4-dicarbonyl compounds by photoreaction of ketones in the presence of oxidants

Phenyl alkyl ketones were photo-irradiated in the presence of Cr(VI) or Mn(VII) oxidants to yield 1,4-dicarbonyl compounds regiospecifically while 2-octanone gave a regioisomeric mixture of 2,5-, 2,6-, and 2,7-octadiones.     

Chemical syntheses of lipid X and lipid Y,acyl glucosamine 1-phosphates isolated from escherichia coli mutants

Two new phospholipids, 2-N; 3-O-bis (R)-3-hydroxytetradecanoyl-glucosamine 1-phosphate and 2-N-(R) -3-hexadecanoyloxytetradecanoyl-3-O-(R)-3-hydroxytetradecanoylglucosamine 1-phosphate, were synthesized and identified with natural lipid X and lipid Y respectively.     

Endgroup analysis of isolated poly(methyl methacrylate) from graft copolymers of wool

In order to elucidate the termination mechanism in the graft copolymerization of methyl methacrylate to unreduced and reduced wool fibers, graft copolymers were prepared by means of the LiBr–K₂S₂O₈ redox sytem without homopolymer or with K₂S₂O₈ only with homopolymer at 30°C. The graft polymers (PMMA) were isolated almost completely from the wool trunk by an HCI-digestion method, leaving a few amino acid residues on the end of the graft polymers. Dinitrophenylation of the isolated polymer was carried out by various methods. The spectral features were almost the same as for dinitrophenylated amino acids of the usual type such as valine, leucine, and methionine, with a maximum in ultraviolet light at 340–345 mμ. From colorimetric analysis of the number of dinitrophenylated amino acid endgroups and the measurement of the average molecular weight of the isolated polymers, the number of amino acid endgroups linked to the graft polymers was calculated to be about one and two per polymer chain in reduced and unreduced wool, respectively, independent of the reaction system, graft-on, and molecular weight of graft polymers. From these facts, it was suggested that the most of isolated polymers are the truly grafted polymers. Also, the termination reactions have been explained as follows. In the unreduced wool, the restriction of mobility of the radical end might be expected, for the confinement of growing chains in wool fibers. This would be favorable to termination by recombination rather than by the disproportionation, since the former has a lower activation energy than the latter. Thus, the formation of intra- or intermolecular crosslinks might be considered between polypeptide chains. On the other hand, in the reduced wool, the mobility of graft polymers might be considered to be greater than that of unreduced wool because of its open structure. Therefore, termination would be principally by disproportionation between graft polymer radicals.     

Preparation of non-contact ordered array of polystyrene colloidal particles by using a metallic thin film of fused hemispheres

A thin metallic bilayer consists of fused hollow hemispheres of 930 nm in diameter is fabricated by sputter deposition of Ti and Fe at 50 and 5 nm of thickness, respectively, onto an array of spherical polystyrene colloidal particles. The fused metal hemispheres are utilized to assemble polystyrene colloidal particles of smaller diameters (800 nm) into non-contact two-dimensional periodic array by trapping them in the metallic wells.     

Preparations and reactions of 2-trifluoromethylketenimines

Preparations and reactions of a series of 2-trifluoromethylketenimines are described. Trifluoromethylketenimines were prepared from trifluoropropanoic acids via corresponding imidoyl chlorides in good yields. 2-Trifluoromethylketenimine was functionalized at its β-position by electrophilic addition of halide, followed by dehydrohalogenation. Addition of nucleophile at α-position gave trifluoroethylated β-amino acid derivative via 1,3-proton shift.