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71.
[reaction: see text] Treatment of 6-iodo-1-hexene derivatives with trimethylsilylmethyl Grignard reagent in the presence of CoCl(2)(dppb) in refluxing THF affords Heck-type products, methylenecyclopentanes, in good yields. 相似文献
72.
Yasuyuki Kita Kazuhiro Higuchi Yutaka Yoshida Kiyosei Iio Shinji Kitagaki Shuji Akai Hiromichi Fujioka 《Angewandte Chemie (International ed. in English)》1999,38(5):683-686
Seventeen years after the isolation of the promising antitumor antibiotic fredericamycin A, the first asymmetric total synthesis of this compound has been accomplished and thereby its absolute configuration established. The key feature is the regiocontrolled [4+2] cycloaddition of 3 to 2 , which was obtained by the stereospecific rearrangement of 1 . Cp = (−)‐camphanoyl. 相似文献
73.
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75.
A convenient synthesis of 11Z‐9‐demethyl‐9‐((3‐indolyl)methyl)retinal, which has an amino acid residue of tryptophan at the 9 position in retinal, is described using a tricarbonyliron complex. 相似文献
76.
Keiji Nagai Qincui Gu Yuzuri Yasuda Takayoshi Norimatsu Shinsuke Fujioka Hiroaki Nishimura Noriaki Miyanaga Yasukazu Izawa Kunioki Mima 《Journal of polymer science. Part A, Polymer chemistry》2009,47(18):4566-4576
A series of tin‐doped hydroxypropyl cellulose (HPC) lyotropic liquid crystal (LC) was synthesized using a simple process and their properties were characterized using selective reflection, wide‐angle X‐ray diffraction (WAXD), and the band texture observed under polarized optical microscope. The present preparation is applicable for mass production using large substrate with low cost HPC. A cholesteric lyotropic LC phase was observed for the hybrid solution with higher than 40 wt % HPC. After sol–gel condensation, the HPC‐Sn hybrid LC films were calcined at 400 °C and the as‐prepared product was determined to obtain tin dioxide (SnO2) which was characterized using WAXD. The iridescent color and ~2 nm structure seen after the condensation disappeared in the as‐prepared SnO2. Scanning electronic microscope images of the SnO2 showed that the HPC content in the HPC‐Sn hybrid played an important role in controlling the SnO2 morphology. A spectrum of relatively monochromatic extreme ultraviolet (13.5 nm) emission was measured in the as‐prepared SnO2 in comparison with bulk tin and inverse opal SnO2. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4566–4576, 2009 相似文献
77.
Ken-ichiro Suzuki Naomi Takeuchi Kazuhiko Madokoro Chihiro Fushimi Shuiliang Yao Yuichi Fujioka Yoshimasa Nihei 《Analytical sciences》2008,24(2):253-256
The removal properties of diesel exhaust particles (DEP) were investigated using an engine exhaust particle size spectrometer (EEPS), field emission-type scanning electron microscopy (FE-SEM) and time-of-flight secondary ion mass spectrometry (TOF-SIMS). DEP were treated using a dielectric barrier discharge (DBD) reactor installed in the tail pipe of a diesel engine, and a model DBD reactor fed with DEP in the mixture of N(2) and O(2). When changing the experimental parameters of both the plasma conditions and the engine load conditions, we obtained characteristic information of DEP treated with plasma discharges from the particle diameter and the composition. In evaluating the model DBD reactor, it became clear that there were two types of plasma processes (reactions with active oxygen species to yield CO(2) and reactions with active nitrogen species to yield nitrogen containing compounds). Moreover, from the result of a TOF-SIMS analysis, the characteristic secondary ions, such as C(2)H(6)N(+), C(4)H(12)N(+), and C(10)H(20)N(2)(+), were strongly detected from the DEP surfaces during the plasma discharges. This indicates that the nitrogen contained hydrocarbons were generated by plasma reactions. 相似文献
78.
Kubota M Oohara Y Yoshizawa H Fujioka H Hirota K Moritomo Y Endoh Y 《Physical review letters》2003,91(4):047201
We have observed magnetic diffuse signals of the bilayer manganite La1.1Sr1.9Mn2O7 by neutron scattering. Even at the low temperature, 20 K, there is a diffuse signal, which is much stronger than that observed in the high temperatures, 144 and 288 K. This signal cannot be characterized by a bilayer structure as observed at 144 K nor by a monolayer structure as at 288 K, but by a high degeneracy of a canted spin structure. Thus, an observation of this diffuse signal is the direct evidence for the establishment of the canted spin structure in La1.1Sr1.9Mn2O7. 相似文献
79.
When a CO2 gas absorption cell was placed within the optical cavity of a low pressure pulsed HF laser, the specific vibration- rotation line of the HF laser disappeared, which influenced both the intensity and pulse duration of the neighbouring lines. This behavior strongly depends upon the rotational population transfer in HF. By measuring the time response of this behavior, it was found that the rate constant for the rotational population transfer was in the range of 107 s-1 torr-1 for the SF6/H2 lasing mixture. 相似文献
80.
For the purpose of improving the utilization efficiency of the gain bandwidth of active media and generating stable ultrashort light pulses, a passive-active mode locking technique has been applied to a cw Rhodamine 6G dye laser. A sufficient ability of this technique for the elimination of the multiple-pulse operation of the mode locking at a higher pumping level and a longer resonator length has been proved. Observed pulse-width by the SHG autocorrelation technique is 1.4 ps with assuming a sech2 pulse profile. 相似文献