Chemical-structural study on a blue metal-complex pigment of hydrangea by using synthetic 5-O-acylquinic acids
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- Oyama Kin-ichi
- 物国セ
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- Yamada Tomomi
- 情報科学
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- Ito Daisuke
- 情報科学
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- Watanabe Noriyuki
- 情報科学
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- Sekiguchi Yukiko
- 情報科学
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- Suzuki Masako
- 情報科学
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- Kondo Tadao
- 情報科学
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- Yoshida Kumi
- 情報科学
Bibliographic Information
- Other Title
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- 5-O-アシル化キナ酸類の効率的合成によるアジサイの 青色金属錯体色素の化学構造研究
Description
<p>Blue sepal-color of Hydragea macrophylla is due to a metal-complex pigment composed with delphinidin 3-glucoside (1), 5-O-caffeoylquininc acid (2) and/or 5-O-p-coumaroylquinic acid (3) as co-pigments, and Al3+ in an aqueous solution around pH 4.0. However, the structure of the hydrangea-blue complex is still remained obscure. To obtain the structural information of hydrangea-blue complex, we developed an efficient synthetic method of 5-O-acylquinic acids and then carried out spectroscopy studies. For synthesis of 5-O-acylquinic acids, we designed p-methoxybenzyl quinate as a key intermediate. Next, the esterification of the sterically hindered 5-OH group were realized by using improved Tanabe’s method (TsCl/NMI/i-Pr2NEt). For the final deprotection step, we established a TFA- or BCl3/C6HMe5-catalyzed method. 5-O-Acylquinic acids were synthesized in seven steps with 45-60% overall yield. The Vis, CD, and 1H-NMR spectroscopy studies of the reconstructed hydrangea-blue complex were performed by using the synthetic 5-O-acylquinic acids. In highly concentrated acetate buffer (6 M, pH 4.0), we could measure 1H NMR of both the hydrangea-blue complex composed of 1 (5 mM), 2 (10 mM), and Al3+ (10 mM) and a simple 1−Al3+complex. Comparison of those 1H NMR signals indicated that in the hydrangea-blue complex 1 might be under equilibrium between chelating and nonchelating structures having an interaction with 2.</p>
Journal
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- Symposium on the Chemistry of Natural Products, symposium papers
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Symposium on the Chemistry of Natural Products, symposium papers 57 (0), PosterP61-, 2015
Symposium on the Chemistry of Natural Products Steering Committee
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Details 詳細情報について
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- CRID
- 1390001288074203648
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- NII Article ID
- 130007494868
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- ISSN
- 24331856
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- Text Lang
- ja
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- Data Source
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- JaLC
- CiNii Articles
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- Abstract License Flag
- Disallowed