• Nuclear Engineering and Technology
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• v.9 no.1
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• pp.39-44
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• 1977

The configuratior and conformation of N-methyl-C-phenylalkyl-ketimine isomers, Ph-CR=N$CH_3$ (R=H, $CH_3$, $CH_3$CH$_2$), have been studied from extended Huckel molecular orbital calculations. The result shows that the E-configuration of the C=N double bond is favored compared with that of the Z-configuration. The most preferable conformation of the phenyl ring rotamer in N-methyl-C-phenylaldimine and N-methyl-C-phenylmethylketimine are the coplanar forms with regard to the C=N plane, but the conformation of the $CH_3$CH$_2$-rotamer, in N-methyl-C-phenylethyl-ketimine, the gauche form (dihedral angle between C=N and $CH_3$CH$_2$- plane=90$^{\circ}$) is favored.

• Bulletin of the Korean Chemical Society
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• v.28 no.11
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• pp.2020-2024
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• 2007

The article reports the synthesis of a novel bispyridino-18-crown-6 ether, 7-{[(5S,15S)-5,15-diphenyl- 3,6,14,17-tetraoxa-23,24-diazatricyclo[17.3.1.18,12]tetracosa-1(23),8(24),9,11,19,21-hexaen-10-yl]oxy}heptylferrocenamide 6, bearing the C2-symmetric diphenyl substituents as chiral barriers and the ferrocenyl groups serving as an electrochemical sensor, and its electrochemical study with D- and L-AlaOMe·HCl as the guest by cyclovoltametry.

• Bulletin of the Korean Chemical Society
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• v.15 no.12
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• pp.1064-1069
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• 1994

Chlorobis(isoprene)rhodium(Ⅰ) (3), prepared by olefin-exchange reaction of chlorobis(cyclooctene)rhodium dimer (2) with isoprene, reacted with benzaldimine 4 to give iminoacylrhodium(Ⅲ) ${\eta}^3$-1,2-dimethylallyl complex 6. Ligand-promoted reductive elimination of 6 by pyridine and P(OMe)$_3$ produced ${\beta},{\gamma}$-unsaturated ketimine 8, which was readily hydrolyzed to give ${\beta},{\gamma}$-unsaturated ketone 9. Other methyl branched dienes such as 2,3-dimethylbutadiene, 3-methyl-1,3-pentadiene, 2-methyl-1,3-pentadiene, 2,4-dimethyl-1,3-pentadiene, 3-methyl-1,4-pentadiene and 2-methyl-1,4-pentadiene, were applied the synthesis of ${\beta},{\gamma}$-unsaturated ketones. In case of 2,4-dimethyl-1,3-pentadiene, only ${\gamma},{\delta}$ -unsaturated ketone 25, 1,2-addition product, was obtained, may be due to the mono-olefin coordination.

• BMB Reports
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• v.35 no.3
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• pp.306-312
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• 2002

The effects of salts on the biochemical properties of D-amino acid aminotransferase from Bacillus sp. YM-1 have been studied to elucidate both the inhibitory effects of salts on the activity and the protective effects of salts on the substrate-induced inactivation. The results from UV-visible spectroscopy studies on the reaction of the enzyme with D-serine revealed that salt significantly reduced the rate of the formation of the quinonoid intermediate and its accumulation. The kinetic and spectroscopy studies of the reaction with $\alpha$-[$^2H$]-DL-serine in different concentrations of NaCl provided evidence that the rate-limiting step was changed from the deprotonation of the external aldimine to another step(s), presumably to the hydrolysis of the ketimine. Gel filtration chromatography data in the presence of NaCl showed that the enzyme volume was reduced sharply with the increasing NaCl concentration, up to 100 mM. An additional increase of the NaCl concentration did not affect the elution volume, which suggests that the enzyme has a limited number of salt-binding groups. These results provide detailed mechanistic evidence for the way salts inhibit the catalytic activity of D-amino acid aminotransferase.