5 グリコシルハライドと過塩素酸銀との反応 : 配糖体,特にα-D-グリコピラノサイドの一新製法
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概要
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The same rather unstable product (III) was obtained when I or II was treated with silver perchlorate at 0° or -10℃ in an inert solvent such as anhydrous toluene, ether or liquid sulfur dioxide. Methanolysis of III gave a mixture of IV and V in good yield. The proportion of IV and V was varried with conditions used. Treatment of III with tetraethylammonium chloride gave a mixture of I and II in a ratio of 3.9 to 96.1 from which II was isolated in 75% yield. These results, the specific rotation value, and the nmr spectrum support that the structure of III is 3,4,6-tri-O-acetyl-2-chloro-2-deoxy-α-D-glucopyranosyl perchlorate ester but not the corresponding ion. In analogy to the above results, the structure of VIII obtained from VI or VII and silver perchlorate is considered to be 3,4,6-tri-O-acetyl-2-chloro-2-deoxy-α-D-mannopyranosyl perchlorate ester, methanolysis of which gave predominantly IX regardless the conditions used. Compound XII was obtained in the reaction of XI with silver perchlorate as expected. It is of interest to note the ratio of XV and XVI, obtained by the methanolysis of XII, was changed with solvent and conditions used. When liquid sulfur dioxide was used as the solvent, the anomerization of the product was so fast and XV was obtained in good yield. Treatment of XII with tetraethyl-ammonium chloride gave XVII in 59% yield. It is found that unstable β-D-glucopyranosyl chloride can be prepared from the corresponding α-D-glucopyranosyl halide via perchlorate ester in good yield.
- 天然有機化合物討論会の論文
- 1970-10-01
著者
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