We describe regio‐ and enantioselective bromocyclization of difluoroalkenes catalyzed by chiral bisphosphine oxides. Owing to the simultaneous activation of both the brominating reagent and amide substrate, the desired cyclization reaction proceeds smoothly even at low temperature to provide bromodifluoromethyl‐containing oxazolines with a chiral quaternary center in a highly enantioselective fashion (up to 99% ee). This protocol features the use of commercially available brominating reagents and readily accessible chiral catalysts. The regioselectivity and enantioselectivity are influenced by the catalyst structure, the brominating reagent, and the reaction temperature. Under the optimal conditions, 5‐exo cyclization proceeds preferentially compared with 6‐endo cyclization, depending on the electronic properties of the alkene substrates. A gram‐scale synthesis of chiral oxazoline was achieved with as little as 1 mol % of the catalyst.

Corrections for the Background in Atomic Absorption Analysis for Iron and Steel Yoshihide ENDO and Yuki NAKAHARA Synopsis: For the determination of trace elements in iron, steel and iron are by atomic absorption analysis, the state of and the correction for influences by "the brackground" are studied. Following three methods for the correction for backgrounds are suggested. 1) Correction with blank-test of pure iron treated in the same way as provided samples. 2) Correction with the transmittance of several elements other than the objective ones in provided solutions by the use of the emissive line near the analytical line. 3) Correction with the transmittance of several elements at the analytical line in the continuous spectrum by H2 hollow cathode lamp. The first can be applied with satisfaction to the correction for the background of Fe, but not for other coexisting elements. The second can be applied to any coexisting elements, but not at the analytical lines influenced with the spectrum interference. The third cannot be applied to the samples containing much Fe, because of the spectrum interference by the analytical line of Fe on the measurement at continuous spectrum.

by Atomic-Absorption SpectrophotometryYoshihide ENDO, Toshihiko HATA and Yuki NAKAHARA Synopsis :An accurate, precise and rapid method has been presented for the atomic absorption spectrophotometric determination of Mn, Cu, Ni, Cr, Mo, V, Ti and Al in steel.The sample is dissolved in acid. The solution prepared to volume and aliquot is subjected to the atomic absorption analysis of Mo, V, Ti and Al by nitrous-oxide acetylene flame and other elements by air acetylene flame referring to the calibration curves.Influenced by large amounts of Fe and other elements, the determination of Cr and Mo should be done in the presence of the suppressor, NH4C1 for Cr and K2SO4 for Mo.On the determination of Ti, Al was added both for the enhancement of sensitivity and the suppression of other elements.The apparatus employed was a Nippon Jarrell-ash AA-I type with a water cooling fish tail burner having a solot 0.4mm by 50mm.

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The purpose of this study was to evaluate the best phantom for calculating the becquerel calibration factor (BCF) and correction method to obtain the improvement of standardized uptake value (SUV) accuracy in both single photon emission computed tomography (SPECT) and SPECT/CT. Method: A SPECT/CT scanner was used in this study. BCFs were calculated using four phantoms with different cross sections including National Electrical Manufacturers Association International Electrotechnical Commission body phantom (NEMA IEC body phantom) filled with 99m TcO4 -, and five correction methods were used for reconstruction. SUVs were calculated by the NEMA IEC body phantom and pediatric phantom in house with these BCFs. We then measured SUVmean in the background region of the NEMA IEC body phantom, SUVmax and SUVpeak of the 37-mm-diameter sphere. Results: In the SPECT scanner, SUVmean and SUVmax measured 1.04 and 4.02, respectively, in the case of BCF calculation and SUV measurement using NEMA IEC body phantoms without corrections. In the SPECT/CT scanner, SUVmean with CT attenuation correction (AC) was in agreement with the theoretical values using each phantom. SUVmax showed the same trend. Conclusion: In the SPECT scanner, it is possible to obtain a highly accurate SUV by using a phantom that matches the size of the subject for BCF calculation and without correction. In the SPECT/CT scanner, highly accurate SUVs can be obtained by using CT-based attenuation correction, and these values do not depend on the size of the BCF calculation phantom.