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91.
Katsuya Ishiguro Kohtaro Tomizawa Yasuhiko Sawaki Hiizu Iwamura 《Tetrahedron letters》1985,26(31):3723-3726
A tracer study for the rearrangement of carbonyl oxides to esters using doubly-labeled oxygen lead to a conclusion that carbonyl oxides do not isomerize directly to dioxyranes and the rearrangement to esters proceeds via a cyclic tetroxide. 相似文献
92.
93.
94.
Yokoyama K Kudo F Kuwahara M Inomata K Tamegai H Eguchi T Kakinuma K 《Journal of the American Chemical Society》2005,127(16):5869-5874
The doubly functional aminotransferase BtrS in the 2-deoxystreptamine (DOS) biosynthesis, in which two transaminations are involved, was characterized by a genetic as well as a chemical approach with the heterologously expressed enzyme. The gene disruption study clearly showed that BtrS is involved, in addition to the previously confirmed first transamination, in the second transamination as well. This dual function of BtrS for the DOS biosynthesis was further confirmed by the structural determination of the reverse reaction product from DOS. Enantiospecific formation of the reverse reaction product from DOS clearly showed that BtrS distinguishes the enantiotopic amino groups of DOS, but in contrast, both enantiomers of 2-deoxy-scyllo-inosose (DOI) were efficiently accepted by BtrS to give a racemic product. This unique stereochemical recognition of DOI chirality and DOS prochirality by BtrS is mechanistically explained by a specific hydrogen-bond donating force in the enzyme active site as a particular feature of this doubly functional enzyme. 相似文献
95.
Yamamoto K Sunagawa Y Takahashi H Muramatsu A 《Chemical communications (Cambridge, England)》2005,(3):348-350
Single nanometer-sized metallic Ni particles have been successfully deposited inside a hexagonally ordered mesoporous silica material by using a liquid-phase reductive deposition method. 相似文献
96.
97.
The elastic moduli and Debye temperatures of LiAl, LiIn, LiZn, NaIn and NaTl (NaTl type: space group Fd3m) have been determined at room temperature by an ultrasonic pulse transmission technique. The trend between the isotropic bulk modulus (B) and the volume per atom pair () shows that the simple coulombic form of ion-ion interaction is not applicable to the NaTl type structure, while the semiconductor like diamond- or ZnS-, and ionic CsCl-type crystals have contributions from a coulombic attractive force. The bonding character of the NaTl structure is also discussed. 相似文献
98.
99.
Koyama M Hayakawa J Onodera T Ito K Tsuboi H Endou A Kubo M Del Carpio CA Miyamoto A 《The journal of physical chemistry. B》2006,110(35):17507-17511
To study the atomistic behavior of the phosphoric ester molecule on the nascent Fe surface under boundary lubrication conditions, we adopted a hybrid tight-binding quantum chemical molecular dynamics method. First, we investigated chemical interactions between phosphoric ester and the nascent Fe surface. Phosphoric ester was shown to interact with the nascent Fe surface, forming both covalent and ionic bonds. Formation and dissociation dynamics of covalent bonds during tribochemical reaction was clearly observed during the simulation. The effect of friction condition on the tribochemical reaction dynamics was then studied, and it was indicated that friction would influence the formation and the dissociation of covalent bonds. By using a hybrid tight-binding quantum chemical molecular dynamics method, we obtained insights on initial tribochemical reaction processes for the formation of tribofilm from the phosphoric ester molecule on the nascent Fe surface. 相似文献
100.
Mathew SP Klussmann M Iwamura H Wells DH Armstrong A Blackmond DG 《Chemical communications (Cambridge, England)》2006,(41):4291-4293
Kinetic evidence supports the role of the reaction product in the catalytic cycle of proline-mediated alpha-aminoxylation and alpha-amination reactions, providing both design principles as well as a model for the evolution of efficiency in catalysis. 相似文献