Zinc-metal promoted selective α-haloacylation and gem-bisacylation of alkyl aldehydes in the presence of chlorotrimethylsilane

Treatment of a mixture of alkyl aldehydes (1) with acid chlorides (2) in the presence of zinc metal powder and a catalytic amount of chlorotrimethylsilane (TMSCl) in dichloromethane brought about highly facile and effective coupling to give selectively the corresponding α-haloacylation and gem-bisacylation products, α-haloalkyl carboxylates and 1,1-dicarboxylates (acylals), in good to excellent yields.     

Study of dependence of quasi-particle alignment on proton and neutron numbers in A = 80 region through g-factor measurements

Dependence of quasi-particle alignment on proton and neutron numbers has been studied in A?=?80 mass region through g-factor measurements by using TMF-IMPAD. The experimental results show that for the nuclides ⁸⁴Zr, ⁸⁵Zr and ⁸⁶Zr with Z?=?40 the proton alignment is followed by the neutron alignment in ⁸⁴Zr and ⁸⁵Zr, while the neutron alignment is followed by the proton alignment in ⁸⁶Zr, and for the nuclides ⁸²Sr, ⁸³Y, ⁸⁴Zr and ⁸⁵Nb with N?=?44 the proton aligns only in ⁸²Sr, the proton alignment occurs first that is followed by the neutron alignment in ⁸³Y and ⁸⁴Zr and the neutron alignment is followed by the proton alignment in ⁸⁵Nb. Proton and/or neutron alignments lead to different patterns of the g-factor variation with spin.     

Facile synthesis of glycerol carbonate from glycerol using selenium‐catalyzed carbonylation with carbon monoxide

The commercial production of glycerol has increased considerably for several years, because of its rising inevitable formation as a by‐product of biodiesel. For the effective utilization of glycerol, a new synthesis of glycerol carbonate (4‐hydroxymethyl‐2‐oxo‐1,3‐dioxolane) that is used as solvents and raw material of plastics from glycerol was explored. By combined the selenium‐catalyzed carbonylation of slightly excess of glycerol with carbon monoxide and potassium carbonate under 0.1 MPa at 20°C for 4 h in DMF with the oxidation of resulting selenocarbonate salt with molecular oxygen (0.1 MPa, 20 °C) for 2 h, glycerol carbonate was obtained in good yields (83–84%). However, sodium hydride to form sodium alkoxide in situ lowered the yield of glycerol carbonate. Use of triethylamine, 1‐methylpyrrolidine, and DBU as bases gave poor results. Furthermore, styrene carbonate was obtained in excellent yield (90%) under similar reaction conditions. The catalytic synthesis of glycerol carbonate was also brought about in the mixed gas atmosphere (carbon monoxide:oxygen = 3:1, 0.1 MPa, 20°C). Glycerol carbonate and styrene carbonate were obtained in reasonable yields (197% and 119%, based on selenium used). © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:541–545, 2010; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20640     

Effect of adhesion force between crack planes on subharmonic and DC responses in nonlinear ultrasound

Subharmonic and DC responses in nonlinear ultrasound have been expected as a possible means of detecting closed cracks. Recently, it has been reported that subharmonics in a closed crack markedly increases above a certain input wave amplitude. Such a phenomenon is called "threshold behavior". However, the mechanism of threshold behavior has yet to be elucidated. To clarify this, we introduced adhesion force as a short-range force into the previous analytical model, which expresses the nonlinear contact vibrations of crack planes with intense ultrasound and provides a DC displacement as an approximation of the subharmonic response. Consequently, upward convex curves of displacement against input wave amplitude above the threshold were reproduced for the first time. The validity of the derived analytical solution is discussed by comparison with experimentally observed subharmonics.     

High-performance liquid chromatographic determination of sulphobromophthalein and its conjugates.

A simple, sensitive and selective high-performance liquid chromatographic method for the determination of sulphobromophthalein and its mercaptide conjugates in rat bile was developed. These pigments, which have an absorption maximum at 580 nm in alkaline solution, were separated isocratically on an alkali-resistant ODS column by paired-ion chromatography. Analysis of bile samples obtained after intravenous administration of sulphobromophthalein to rats showed the presence of at least twenty peaks of metabolites, of which thirteen were identified and seven quantified.     

Hyperfine interaction of13O and23Mg implanted in Pt

The spin relaxation timeT ₁ for short-lived beta emitters¹³O and²³Mg implanted in Pt have been measured for the first time;T ₁T¹³O) = 2.90 ±0.65 Ks andT ₁ T(²³Mg) = 1665 ±140 Ks. The Knight shift for¹³O in Pt was measured at 300 K to beK(¹³O) = +(4.23 ±0.14) × 10^–3. In the case of¹³O, the Knight shift is unusually large and the relaxation time is unusually fast compared with other interstitial impurities in Pt. A KKR band-structure calculation reproduces the present large Knight shift fairly well.     

Hyperfine interaction of 25Al in α-Al2O3 and its quadrupole moment

A brief review is presented of recent work with the Precision Penning Trap Mass Spectrometer, formerly at MIT, now at Florida State University. This includes atomic mass comparisons using single trapped ions; mass comparisons using two simultaneously trapped ions alternated between large and small cyclotron radii; and measurement of the dipole moment of a molecular ion using the polarizability-induced shift in cyclotron frequency.     

Fixation of a cholesteric helical structure by the photopolymerization of a cholesteryl derived monomer

A cholesteryl derived monomer was synthesized according to a conventional synthetic route; it exhibits a cholesteric phase above 129°C, and shows a red colour due to selective reflection in the cholesteric phase. Photopolymerization of the monomer was carried out at 135°C in the cholesteric phase. The helical structure of the cholesteric phase of the monomer was frozen by photopolymerization. A peak based on the selective reflection of the cholesteric phase was detected at 615 nm in the transmittance UV-Vis spectrum. Mixtures of the monomer with a binaphthyl derivative were prepared to control the selective reflection wavelength; they all also exhibited a cholesteric phase. The selective reflection wavelength of the mixture was dependent upon the ratio of the binaphthyl derivative in the mixture. This wavelength became shorter with increasing ratio of the binaphthyl derivative. The polymer films obtained by photopolymerization displayed almost the same selective reflection wavelength as the corresponding mixtures before photopolymerization. The selective reflection wavelength of the polymer films did not change up to about 250°C.     

Correlation between proton magnetic resonance spectroscopic lactate measurements and vascular reactivity in chronic occlusive cerebrovascular disease: a comparison with positron emission tomography

The purpose of this study is to investigate the correlation between lactate levels and cerebral vascular reactivity (VR) in regions outside an area of chronic cerebral infarction. Multivoxel proton magnetic resonance spectroscopy ((1)H-MRS) and positron emission tomography (PET) were performed in 11 patients who suffered chronic cerebral infarction. Of these 11 patients, 4 were examined before and after bypass surgery. Two regions-of-interests (ROIs) were placed outside the area of chronic infarction. One ROI was placed within a control region on the contralateral side. A lactate peak area was obtained in all ROIs. An N-acetyl aspartate (NAA) peak area was obtained in the ROI within the control region. The ratio of the lactate peak area and NAA peak area (Lct/NAA) was calculated for normalization of the lactate level, and was found to be 0.13 +/- 0. 10 (range, 0 to 0.43). The VR was recorded at 13.3 +/- 20.7% (range, - 44.3 to 68.9%), utilizing PET and administering acetazolamide. A significant negative correlation was observed between the Lct/NAA ratio and VR (r = - 0.709, p < 0.0001). These results suggest that lactate levels and VR are closely related in regions outside areas of chronic cerebral infarction.