| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1996: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1995: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
During our studies of the epimerization of aldohexoses and aldopentoses by Ni (II)-diamine system, it became apparent that in the course of the reaction (1-13C)-D-glucose (1^<**>-Glc) was changed into (2-13C)-D-Mannose (2^<**>-Man) not through so called en-diol rearrangement (Lobry de Bruyn, Alberta van Ekenstein rearrangement) but through the sterospecific rearrangement of carbon skelton. 1) And it was also elucidated that the coordinating state of the complex composed of ternary elements, i.e., metal, diamine and sugar, playd an important role in this reaction. Since the explanation for these findings, a large number of approaches were complehensively studied to clarify the influence of reaction conditions on the epimerization processes. 2,3,4)
I prepared three kinds of optically active diamines, and evaluated the effects of the chirality on the epimerization of aldoses. These amines were 1-phenylethylenediamine, 1-benzylethylenediamine and 1-methylethlenediamine. When the epimerization reaction was carried out in an ethanol solution, the difference in the rate of epimerization and equilibrium between two C-2 aldoses became more distinct. When we ran the epimerization with the (R)-isomer, a larger proportion of mannose was formed and the reaction rrequired a longer time to reach the equilibrium. Furthermore, the position of the equilibrium shifted to the mannose side as the bulkiness of a substitution group of ethylenediamines at C-lincreased.
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