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141.
Novel water-soluble Cp*Ir-ammine complexes have been synthesized, and a new and highly atom-economical system for the synthesis of organic amines using aqueous ammonia as a nitrogen source has been developed. With a water-soluble and air-stable Cp*Ir-ammine catalyst, [Cp*Ir(NH(3))(3)][I](2), a variety of tertiary and secondary amines were synthesized by the multialkylation of aqueous ammonia with theoretical equivalents of primary and secondary alcohols. The catalyst could be recycled by a facile procedure maintaining high activity. A one-flask synthesis of quinolizidine starting with 1,5,9-nonanetriol was also demonstrated. This new catalytic system would provide a practical and environmentally benign methodology for the synthesis of various organic amines. 相似文献
142.
Kentaro Yoshimura Lee Chuin Chen Mridul Kanti Mandal Tadao Nakazawa Zhan Yu Takahito Uchiyama Hirokazu Hori Kunio Tanabe Takeo Kubota Hideki Fujii Ryohei Katoh Kenzo Hiraoka Sen Takeda 《Journal of the American Society for Mass Spectrometry》2012,23(10):1741-1749
Immediate diagnosis of human specimen is an essential prerequisites in medical routines. This study aimed to establish a novel cancer diagnostics system based on probe electrospray ionization-mass spectrometry (PESI-MS) combined with statistical data processing. PESI-MS uses a very fine acupuncture needle as a probe for sampling as well as for ionization. To demonstrate the applicability of PESI-MS for cancer diagnosis, we analyzed nine cases of clear cell renal cell carcinoma (ccRCC) by PESI-MS and processed the data by principal components analysis (PCA). Our system successfully delineated the differences in lipid composition between non-cancerous and cancerous regions. In this case, triacylglycerol (TAG) was reproducibly detected in the cancerous tissue of nine different individuals, the result being consistent with well-known profiles of ccRCC. Moreover, this system enabled us to detect the boundaries of cancerous regions based on the expression of TAG. These results strongly suggest that PESI-MS will be applicable to cancer diagnosis, especially when the number of data is augmented. 相似文献
143.
Muhammad S Minami T Fukui H Yoneda K Kishi R Shigeta Y Nakano M 《The journal of physical chemistry. A》2012,116(5):1417-1424
Quantum molecular engineering has been performed to determine the second-order nonlinear optical (NLO) properties in different halo complexes of decaborane (B(10)H(14)) and their derivatives using the density functional theory (DFT) method. These decaborane halo complexes of X(-)@B(10)H(14) (X = F, Cl, Br, and I) are found to possess noncovalent charge transfer interactions. The static polarizability (α(0)) and first hyperpolarizability (β(0)) among these complexes increase by moving down the group from F to I, partly due to the increase in size of their anionic radii and the decrease in their electron affinities. A two-level approximation has been employed to investigate the origin of β(0) values in these halo complexes, which show very consistent results with those by the finite-field method. Furthermore, in the same line, two experimentally existing complexes, I(-)@B(10)H(14) and I(-)@2,4-I(2)B(10)H(12), are found to have considerably large β(0) values of 2859 and 3092 a.u., respectively, which are about three times larger than a prototypical second-order NLO molecule of p-nitroaniline, as reported by Soscun et al. [Int. J. Quantum Chem.2006, 106, 1130-1137]. Besides this, the special effects of solvent, counterion, and bottom substitutions have also been investigated. Interestingly, 2,4-alkali metal-substituted decaborane iodide complexes show remarkably large second-order NLO response with β(0) amplitude as large as 62436 a.u. for I(-)@2,4-K(2)B(10)H(12) complex, which are explained in terms of their transition energies, frontier molecular orbitals and electron density difference plots. Thus, the present investigation provides several new comparative insights into the second-order NLO properties of halo complexes of decaborane, which possess not only large first hyperpolarizabilities, but also high tunability to get a robustly large second-order NLO response by alkali metal substitution effects. 相似文献
144.
Toshifumi Miyazawa Manabu Hamada Ryohei Morimoto Takashi Murashima Takashi Yamada 《Tetrahedron letters》2008,49(1):175-178
Candida antarctica lipase B (CAL-B) was found to be a highly active biocatalyst for the direct acylation of the phenolic hydroxyls of substituted hydroquinones and resorcinols with vinyl propanoate as an acyl donor. The acylation reactions took place generally in a very regioselective manner. Especially in the case of 4-substituted resorcinols, the hydroxyl remote from the substituent was regiospecifically acylated to afford only the 1-O-propanoylated resorcinols. 相似文献
145.
Makoto Obata Shigenobu Yano Kazunobu Kamino Kazuaki Yokota Toyoji Kakuchi 《Journal of polymer science. Part A, Polymer chemistry》2004,42(18):4671-4681
The asymmetric cyclocopolymerization of bis(4-vinylbezoate) of a chiral diol with styrene is a promising method for the preparation of optically active polystyrene derivatives because of main-chain chirality. However, the mechanism for chirality induction from the chiral diol to the main chain is still unknown. To clarify the chirality induction mechanism, we carried out the radical cyclizations of (2S,3S)-2,3-butanediyl bis(4-vinylbenzoate), (2S,4S)-2,4-pentanediyl bis(4-vinylbenzoate), and (2S,5S)-2,5-hexanediyl bis(4-vinylbenzoate) with tri-n-butyltin hydride or allyltri-n-butyltin as a chain-transfer reagent as model reactions for asymmetric cyclocopolymerization. The absolute configuration was determined with single-crystal X-ray crystallography and a circular dichroism exciton chirality method. The distribution of the stereoisomer showed (R)-configuration selectivity (21–34% diastereomeric excess) in the intramolecular cyclization and an extremely low extent (<1%) of the (S,S)-cyclized product among the four stereoisomers. Therefore, chirality induction is caused by the selective inhibition of the (S,S)-racemo configuration. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4671–4681, 2004 相似文献
146.
Toshifumi Miyazawa Manabu Hamada Ryohei Morimoto Takashi Murashima Takashi Yamada 《Tetrahedron letters》2007,48(47):8334-8337
Candida antarctica lipase B (CAL-B) was found to be highly regioselective as well as active in the deacylation of resorcinols and hydroquinones acylated at both phenolic hydroxyls. Contrary to expectation, secondary alcohols acted as better nucleophiles than primary alcohols in these enzymatic deacylations. 相似文献
147.
148.
A novel method for the calculation of the dynamic polarizability (α) of open-shell molecular systems is developed based on the quantum master equation combined with the broken-symmetry (BS) time-dependent density functional theory within the Tamm-Dancoff approximation, referred to as the BS-DFTQME method. We investigate the dynamic α density distribution obtained from BS-DFTQME calculations in order to analyze the spatial contributions of electrons to the field-induced polarization and clarify the contributions of the frontier orbital pair to α and its density. To demonstrate the performance of this method, we examine the real part of dynamic α of singlet 1,3-dipole systems having a variety of diradical characters (y). The frequency dispersion of α, in particular in the resonant region, is shown to strongly depend on the exchange-correlation functional as well as on the diradical character. Under sufficiently off-resonant condition, the dynamic α is found to decrease with increasing y and/or the fraction of Hartree-Fock exchange in the exchange-correlation functional, which enhances the spin polarization, due to the decrease in the delocalization effects of π-diradical electrons in the frontier orbital pair. The BS-DFTQME method with the BHandHLYP exchange-correlation functional also turns out to semiquantitatively reproduce the α spectra calculated by a strongly correlated ab initio molecular orbital method, i.e., the spin-unrestricted coupled-cluster singles and doubles. 相似文献
149.
Ogoshi T Shiga R Hashizume M Yamagishi TA 《Chemical communications (Cambridge, England)》2011,47(24):6927-6929
Introduction of bulky substituents such as benzyl and pyrenyl groups using click reactions inhibited or slowed the rotation of the units on the NMR chemical shift timescale. The perpyrenylated pillar[5]arene showed a thermally-responsive excimer emission, but a unit model of the perpyrenylated pillar[5]arene did not exhibit such a response. 相似文献
150.
The major advancement outlined in this communication is the simultaneous visualisation of two kinds of nitroxyl radicals using electron paramagnetic resonance (EPR) spectroscopy and imaging. 相似文献