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21.
The methyl transfer occurring in the production of methyl N,N-dimethyl-γ-aminobutyrate by pyrolysis of carpronium chloride was examined by means of pyrolysis gas chromatography mass spectrometry with the aid of some deuterated compounds. The mass spectra of methyl N,N-dimethyl-γ-aminobutyrate, produced from deuterated derivatives of carpronium chloride, showed inter alia, characteristic molecular ion peaks which indicated that the methyl of the trimethylammonium group transfers and displaces the methyl of the carbomethoxy group of the tertiary amino compound. The results show that an intermolecular methyl transfer occurs in part on pyrolysis of carpronium chloride, to form methyl N,N-dimethyl-γ-aminobutyrate in which the methyl oxygen is replaced by a methyl from the nitrogen of the original compound. The mechanism presented involves the bimolecular reaction between zwitterionic intermediates formed by ionic O-demethylation of carpronium chloride. 相似文献
22.
The resonance Raman spectra of tris(acetylacetonatoiron(III)) and ruthenium(III) complexes in various solvents and in water-acetonitrile (W-AN) mixtures were measured. The resonance Raman spectra of both complexes indicated peaks near 460 and around 1580 cm–1. Thev(C-O) peak (around 1580 cm–1) is shifted to low frequency with an increase in the dielectric constant T of the solvents, whereas thev(M-O) (M=Fe and Ru, near 460 cm–1) are constant, independent of T. It implies that the C-O bond in the acac– ligand is lengthened by the polarizability effect of the solvents, while both the Fe-O and Ru-O bonds, which are located in the inside of the complexes, are not influenced by the solvents indicating that the interaction does not depend on the properties of individual solvent molecules but on those of the aggregate. 相似文献
23.
Kazumi Ohya Hiroaki Kitaoka Yasuhiko Yotsui Mitsuji Sano 《Journal of mass spectrometry : JMS》1983,18(4):139-146
The mechanism of the pyrolysis reaction of carpronium chloride [(CH3)3N+? (CH2)3? COOCH3CI?] leading to γ-butyrolactone and tetramethylammonium chloride was investigated by means of thermal analysis, pyrolysis gas chromatography mass spectrometry and field desorption mass spectrometry, using deuterium labelling. The results indicated that carpronium chloride pyrolysed to yield equimolar amounts of γ-butyrolactone and tetramethylammonium chloride, methyl transfer occurred between N and O during the pyrolysis process. The mechanism is discussed on the basis of the experimental results, and with the aid of the theoretical results calculated by the CNDO/2 method. The mechanism presented is as follows. γ-Butyrolactone is formed by the intramolecular migration of the π-orbital of C?O to the carbon adjacent to [(CH3)3N]+ via a 5-membered ring transition state, accompanied by a bimolecular reaction between [(CH3)3N]+ and the CH3 of O? CH3, resulting in the formation of tetramethylammonium chloride in an amount equimolar with γ-butyrolactone. 相似文献
24.
Katsuya Maeyama Kenji Yamashita Shugo Maeda Noriyuki Yonezawa Shunichi Aikawa Yasuhiko Yoshida 《合成通讯》2013,43(23):4158-4170
Optically active aromatic ether ketone macrocycles containing 2,2′-dimethoxy-1,1′-binaphthyl-6,6′-diyl moieties were synthesized through electrophilic aromatic substitution reaction and stepwise nucleophilic aromatic substitution reactions. Structures of the resulting macrocycles were confirmed by NMR and matrix assisted laser desorption/ionization time of flight (MALDI-TOF) mass measurements. 相似文献
25.
A system of q-Painlevé type equations with multi-time variables t
1,...,t
M
is obtained as a similarity reduction of the N-reduced q-KP hierarchy. This system has affine Weyl group symmetry of type
. Its rational solutions are constructed in terms of q-Schur functions. 相似文献
26.
Within the framework of the LCAO -MO theory, a novel sign-alternation rule has been found empirically for the lowest excited ππ* triplet state in the alternant aromatic system. This rule can be applied to identify the phosphorescent state. 相似文献
27.
The heats of fusion of methoxycarbonyl-benzenes (12 isomers) and -naphthalenes (32 isomers) have been determined by the differential scanning calorimetric method and the correlation of numbers and positions of methoxycarbonyl groups against the parameters of fusion (melting point, enthalpy and entropy) are discussed. The enthalpy—entropy relationship shows two correlation lines depending on the symmetry of the molecules including the positions of the substituents. 相似文献
28.
Yasuhiko H. Mori Hiroshi Sano Kazunari Komotori 《International Journal of Multiphase Flow》1980,6(3):255-266
Cinemicrophotography is applied to the boiling of emulsions of water dispersed in oils whose boiling points are higher than that of water. The layer of emulsion is made thin enough to make possible a microscopic observation by transmitted light through the layer. Two alternative processes of bubble formation are found: a periodical bubble formation at specified sites on the heated solid surface contacting the emulsion and a casual bubble formation some distance away from the surface. The basic mechanisms of those processes are discussed. 相似文献
29.
Ohwada K Fujii Y Katsuki Y Muraoka J Nakao H Murakami Y Sawa H Ninomiya E Isobe M Ueda Y 《Physical review letters》2005,94(10):106401
The present resonant x-ray scattering has been performed on a monoclinically split single domain of NaV(2)O(5). The observation of a critically enhanced contrast between V(4+) and V(5+) ions has led us to the unequivocal conclusion of the charge-order pattern of the low-temperature phase of NaV(2)O(5) below T(c) = 35 K. In spite of the possible four types of configuration of the zigzag-type charge-order patterns in the ab plane (A,A',B and B'), the stacking sequence along the c axis is determined as the AAA'A' type by comparison with model calculations. 相似文献
30.
Murakami T Nishikiori T Nohira T Ito Y 《Journal of the American Chemical Society》2003,125(2):334-335
Ammonia was successfully synthesized by using a new electrochemical reaction with high current efficiency at atmospheric pressure and at lower temperatures than the Haber-Bosch process. In this method, nitride ion (N3-), which is produced by the reduction from nitrogen gas at the cathode, is anodically oxidized and reacts with hydrogen to produce ammonia at the anode. 相似文献