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91.
Chiral Bis(imidazolidine)‐Derived NCN Pincer Rh Complex for Catalytic Asymmetric Mannich Reaction of Malononitrile with N‐Boc Imines
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Prof. Dr. Takayoshi Arai Takuma Moribatake Prof. Dr. Hyuma Masu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(30):10671-10675
Chiral bis(imidazolidine)‐derived NCN–rhodium complexes ([PhBidine‐RhX2] and [tBu‐PhBidine‐RhX2]) were prepared by a C?H insertion method, and the structures were unequivocally determined by X‐ray crystallographic analysis. The [tBu‐PhBidine‐Rh(OAc)2] complex smoothly catalyzed an asymmetric Mannich reaction of malononitrile with N‐Boc imines to give products in up to 94 % ee, which are useful for the synthesis of chiral α‐amino acids. 相似文献
92.
93.
Toshiyasu Arai 《Archive for Mathematical Logic》2011,50(3-4):395-409
In this note we will introduce a class of search problems, called nested Polynomial Local Search (nPLS) problems, and show that definable NP search problems, i.e., ${\Sigma^{b}_{1}}$ -definable functions in ${T^{2}_{2}}$ are characterized in terms of the nested PLS. 相似文献
94.
A four-step synthetic route to fully substituted chiral tetrahydro-β-carbolines (THBCs) is described. Starting from the (R,S,S)-Friedel-Crafts/Henry adduct obtained from three-component coupling of an indole, nitroalkene, and aldehyde catalyzed by imidazoline-aminophenol-CuOTf, the (1S,3S,4R)-THBCs were readily synthesized in a three-step operation including reduction of the nitro-functionality and Pictet-Spengler cyclization. 相似文献
95.
Urea compounds are useful anion sensors due to their hydrogen-bonding capabilities. We investigated the emissive properties of complexes consisting of urea-anthracene (nPUA, n = 1, 2) host compounds and acetate anions held as guests through intermolecular hydrogen bonding. The kinetics of a new emission band formed by conformational changes in the excited singlet state were revealed. The new band is thought to arise from a charge-transfer interaction between the anthracene and urea moieties after intermolecular hydrogen-bond reconfiguration in the excited state, with rate constants of 2.4 × 10(9) and 4.0 × 10(7) s(-1) for 1PUA and 2PUA, respectively. 相似文献
96.
Inoue K Kitahara K Aikawa Y Arai S Masuda-Hanada T 《Molecules (Basel, Switzerland)》2011,16(7):5905-5915
To investigate the separations of all aldopentoses (ribose, arabinose, xylose and lyxose) and aldohexoses (glucose, galactose, allose, altrose, mannose, gulose, idose and talose) on the D? stationary phase prepared by the reaction of chloromethylated styrene-divinylbenzene copolymer and N,N,N',N'-tetramethyl-1,6-diaminohexane, we examined the effect of varying the concentration of the NaOH eluent on the elution orders. Separations of these aldoses were achieved using a 20 mM NaOH eluent. The elution behaviors of the aldoses were probably due to not only the individual pK(a) values, but also the chemical structures of the cyclic aldoses. 相似文献
97.
The X-ray diffraction measurement for superionic conducting glass 5Agl–3Ag2O–2V2O5 was carried out at 12, 100, 200 and 290 K. The temperature dependence of structure factor S(Q) of 5Agl–3Ag2O–2V2O5 has been discussed based on the theoretical treatment that includes thermal vibration of atoms in noncrystalline materials. The effective overall Debye–Waller temperature parameter B increases with the increase of temperature. 相似文献
98.
Arai M. Sakuma T. Atake T. Kawaji H. 《Journal of Thermal Analysis and Calorimetry》2002,69(3):905-908
The phase transition and the crystal structures of CuITe were investigated by differential thermal analysis and X-ray powder
diffraction measurements in the temperature range between 300 and 683 K. The new phase transition in CuITe was observed at
592 K. The enthalpy of transition is ΔH=0.125 kJ mol-1. The new phase above 592 K belongs to tetragonal system with the space group I41
/amd.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
99.
Hiroshi Sugaya Takafumi Arai Youichi Ueda 《Journal of magnetism and magnetic materials》1993,120(1-3):106-111
A contact printing model is introduced to explain the re-recording dip in overwrite recording. The first signal on a recording medium is transferred to the medium surface, where the second signal increases the susceptibility to transfer the S-1 signal magnetically with opposite phase. The output signal of S-1 will be compensated by the transferred signal, and will be zero, which is supposed to be the re-recording dip. The contact printing model is confirmed by experiments. 相似文献
100.
Summary A high-performance gel-permeation chromatographic (GPC) method is described for the determination of serum haptoglobin (Hp),
based on the estimation of the haptoglobin-hemoglobin (Hp−Hb) complex. Hemoglobin (Hb) is added to the serum and the resulting
Hp−Hb complex is separated by GPC and detected at 415 nm. The Hp−Hb complex separated chromatographically from serum migrated
electrophoretically with the globulin fraction. It was found to be stable over a period of one week at 4°C. The total analysis
time for a serum sample is approximately 20 min. The minimum detection limit is 30mg/L. Relative standard deviation values
were below 1% (peak area). No interferences from bilirubin or from turbidity of samples were observed. The results of the
GPC analysis correlate well with those obtained by nephelometric assay (r=0.996). 相似文献