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91.
Under photoirradiation conditions using a xenon light, and in the presence of PdCl(2)(PPh(3))(2) as a catalyst, four-component coupling reactions comprising of α-substituted iodoalkanes, alkenes, carbon monoxide, and alcohols proceeded smoothly to give functionalized esters in good yields. When alkenyl alcohols were used as acceptor alkenes, three-component coupling reactions accompanied by intramolecular esterification proceeded to give lactones in good yields. The present reaction system represents the vicinal C-functionalization of alkenes. 相似文献
92.
Takahide Kurokawa 《Potential Analysis》2011,34(3):261-282
Let S(Rn){\cal S}(R^n) be the Schwartz space on R
n
. For a subspace V ì S(Rn)V\subset {\cal S}(R^n), if a subspace W ì S(Rn)W \subset {\cal S}(R^n) satisfies the condition that S(Rn){\cal S}(R^n) is a direct sum of V and W, then W is called a complementary space of V in S(Rn){\cal S}(R^n). In this article we give complementary spaces of two kinds of the Lizorkin spaces in S(Rn){\cal S}(R^n). 相似文献
93.
Yamamoto Y Yamashita K Nishiyama H 《Chemical communications (Cambridge, England)》2011,47(5):1556-1558
A ruthenium cyclic biscarbene complex reacted with a H(2)O molecule under mild conditions to produce η(5)-oxapentadienyl complex, that proved to be the intermediate in the catalytic hydrative cyclization of a diyne. 相似文献
94.
H. Sukumar J. A. Stone T. Nishiyama C. Yuan G. A. Eiceman 《International Journal for Ion Mobility Spectrometry》2011,14(2-3):51-59
A paper spray ion source was combined with a drift tube operating at ambient pressure for mobility measurements of ions derived from pharmaceutical solutions. Paper spray ionization with solvent alone resulted in a mixture of ions convolved to a single peak with a reduced mobility of 2.19 cm2/Vs in the mobility spectrum. These were mass-identified principally as m/z 157, (MeOH)2(HCOOH)2H+ and m/z 129, (MeOH)4(H2O)H+ while pharmaceuticals with nitrogen bases formed MH+ product ions. The duration of response was governed by the volume of liquid added to the paper source and was limited by evaporation of solvent in gas at 58 °C venting the drift tube. Quantitative variation was attributed in part to morphologic changes in the tip of the paper spray source. This was associated with mass flow in the electrical discharge and not due alone to cycles of wetting and drying of the paper. Mobility spectra of chlorpromazine in urine, exhibited a single product ion peak and linear response was 30 to 500 ng with an estimated limit of detection of 1.5 ng. Ion flux could be prolonged by continuous addition of liquid and findings portend a combination of paper spray ionization IMS with paper chromatography. 相似文献
95.
96.
97.
Muonium spin relaxation measurements of the \alpha‐, \beta‐, and \gamma‐tridymite phases of quartz have been carried out over
a temperature range from 300 to 1250 K. Anomalous relaxation rate increases are observed which may result either from resonance
coupling between the other impurity ions and defects in the lattice and the diffusing muonium, or may result from phonon interactions
with the muonium quadrupole moment.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
98.
Y. Nishiyama 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,6(3):335-340
Ground-state phase diagram of the one-dimensional bond-random S=1 Heisenberg antiferromagnet is investigated by means of the loop-cluster-update quantum Monte-Carlo method. The random couplings
are drawn from a rectangular uniform distribution. We found that even in the case of extremely broad bond distribution, the
magnetic correlation decays exponentially, and the correlation length is hardly changed; namely, the Haldane phase continues
to be realized. This result is accordant with that of the exact-diagonalization study, whereas it might contradict the conclusion
of an analytic theory founded in a power-law bond distribution instead. The latter theory predicts that a second-order phase
transition occurs at a certain critical randomness, and the correlation length diverges for sufficiently strong randomness.
Received: 31 March 1998 / Revised and Accepted: 7 July 1998 相似文献
99.
E. Torikai K. Nishiyama K. Kojima K. Nagamine H. Kitazawa I. Tanaka H. Kojima 《Hyperfine Interactions》1993,79(1-4):879-883
In order to investigate the electronic structure around oxygen in superconducting La2–x
Sr
x
CuO4 (x=0.10 and 0.14), precise measurements were carried out on the paramagnetic Knight shifts in the spin rotation frequency of the negative muon bound to the oxygen with reference to antiferromagnetic La2–x
Sr
x
CuO4 (x=0.05). Remarkable temperature as well as crystalline-axis dependence was observed for the highT
c case with a divergence character towardsT
c. Possible mechanisms to explain the observed results are given. 相似文献
100.
Metabolism of tetrahydrobiopterin: Its relevance in monoaminergic neurons and neurological disorders
Hiroshi Ichinose Takahide Nomura Chiho Sumi‐Ichinose 《Chemical record (New York, N.Y.)》2008,8(6):378-385
(6R)‐L‐erythro‐5,6,7,8‐tetrahydrobiopterin (BH4) is an essential cofactor for aromatic amino acid hydroxylases, such as phenylalanine hydroxylase (PAH), tyrosine hydroxylase (TH), tryptophan hydroxylase, and nitric oxide synthase, which catalyze physiologically important reactions in mammals. The biosynthesis and metabolism of BH4 is usually studied mostly in the liver and only slightly in the brain, as the BH4 level in the liver is relatively high because BH4 is required for the reaction of PAH. We found that GTP (guanosine triphosphate) cyclohydrolase I, an enzyme for the biosynthesis of BH4, is a causative gene for DOPA (3,4‐dihydroxyphenylalanine)‐responsive dystonia (also called Segawa's disease), and that partial deficiency of BH4 leads to the dysfunction of the nigrostriatal dopaminergic neurons without hyperphenylalaninemia. We analyzed BH4‐deficient mice that were produced by disruption of a BH4‐synthesizing gene by a gene‐knockout technique. We found that the protein amount of TH was highly dependent on the amount of BH4, especially in nerve terminals. Our research suggests that BH4 metabolism in the brain should be different from that in the liver, and that altered metabolism of BH4 should lead to neuropsychiatric disorders including Parkinson's disease. © 2008 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 8: 378–385; 2008: Published online in Wiley InterScience ( www.interscience.wiley.com ) DOI 10.1002/tcr.20166 相似文献