Efficient and versatile synthesis of 5-O-acylquinic acids with a direct esterification using a p-methoxybenzyl quinate as a key intermediate

Oyama, Kin‐ichi; Watanabe, Noriyuki; Yamada, Tomomi; Suzuki, Masako; Sekiguchi, Yukiko; Kondo, Tadao; Yoshida, Kumi

doi:10.1016/j.tet.2014.08.064

Cited by 10 publications

(12 citation statements)

References 79 publications

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“…43 5-O-Caffeoylquinic acid, 2, 5-O-p-coumaroylquinic acid, 3, 5-Ocinnamoylquinic acid, 7, 5-O-(3-phenylpropionyl)quinic acid, 8, and 5-O-(3′,4′-dimethoxycinnamoyl)quinic acid, 9, were synthesized according to our procedures. 21 Chlorogenic acid (3-O-caffeoylquinic acid), 4, was purchased (Tokyo Chemical Industry Co., Ltd. (TCI), Japan). AlNH 4 (SO 4 ) 2 ·12H 2 O was purchased (Nacalai Tesque, Inc., Japan).…”

Section: Journal Of Agricultural and Food Chemistrymentioning

confidence: 99%

Metal Complex Pigment Involved in the Blue Sepal Color Development of Hydrangea

Oyama

Yamada

Ito

et al. 2015

J. Agric. Food Chem.

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Anthocyanins exhibit various vivid colors from red through purple to blue and are potential sources of food colorants. However, their usage is restricted because of their instability, especially as a blue colorant. The blue sepal color of Hydrangea macrophylla is due to a metal complex named "hydrangea-blue complex" composed of delphinidin 3-O-glucoside, 1, 5-O-caffeoylquinic acid, 2, and/or 5-O-p-coumaroylquinic acid, 3, as copigments, and Al(3+) in aqueous solution at approximately pH 4.0. However, the ratio of each component ins not stoichiometric, but is fluctuates within a certain range. The hydrangea-blue complex exists only in aqueous solution, exhibiting a stable blue color, but attempts at crystallization have failed; therefore, the structure remains obscure. To clarify the basis of the character of the hydrangea-blue pigment and to obtain its structural information, we studied the mixing conditions to reconstruct the same blue color as observed in the sepals. In highly concentrated sodium acetate buffer (6 M, pH 4.0) we could measure (1)H NMR of both the hydrangea-blue complex composed of 1 (5 mM), 2 (10 mM), and Al(3+) (10 mM) and a simple 1-Al(3+) complex. We also recorded the spectra of complexes composed with structurally different anthocyanins and copigments. Comparison of those signals indicated that in the hydrangea-blue complex 1 might be under equilibrium between chelating and nonchelating structures having an interaction with 2.

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Section: Journal Of Agricultural and Food Chemistrymentioning

confidence: 99%

Metal Complex Pigment Involved in the Blue Sepal Color Development of Hydrangea

Oyama

Yamada

Ito

et al. 2015

J. Agric. Food Chem.

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“…Chemicals used in this study were the same as previously reported 14 . Briefly, 3- O -glucosyldelphinidin (Dp3G; 1 ) was purified from the seed coat of the scarlet bean, Phaseolus coccineus , and the copigments 5- O -caffeoylquinic acid ( 2 ) and 5- O - p -coumaroylquinic acid ( 3 ) were synthesized 13 . 3- O -Caffeoylquinic acid ( 4 ) and trifluoroacetic acid (TFA) were purchased form FUJIFILM Wako Pure Chemical Corporation (Osaka, Japan), and KCl and AlCl 3 · 12H 2 O was purchased from KANTO KAGAKU (Tokyo, Japan).…”

Section: Methodsmentioning

confidence: 99%

“…and 0.03 eq., respectively) 10 . To obtain structural information of the blue complex, we synthesized various natural and unnatural copigments and attempted whether the copigments could reproduce the blue color of the sepals by mixing 1 and Al 3+ in buffered solutions 11–13 . The essential structural elements of the copigment for blue coloration are 1-COOH, 1-OH, and 5- O -aromatic acyl group in the quinate 11,12 .…”

Section: Introductionmentioning

confidence: 99%

Direct mapping of hydrangea blue-complex in sepal tissues of Hydrangea macrophylla

Ito

Aoki

Fukushima

et al. 2019

Sci Rep

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The original sepal color of Hydrangea macrophylla is blue, although it is well known that sepal color easily changes from blue through purple to red. All the colors are due to a unique anthocyanin, 3- O -glucosyldelphinidin, and both aluminum ion (Al 3+ ) and copigments, 5- O -caffeoyl and/or 5- O - p -coumaroylquinic acid are essential for blue coloration. A mixture of 3- O -glucosyldelphinidin, 5- O -acylquinic acid, and Al 3+ in a buffer solution at pH 4 produces a stable blue solution with visible absorption and circular dichroism spectra identical to those of the sepals, then, we named this blue pigment as ‘hydrangea blue-complex’. The hydrangea blue-complex consists of 3- O -glucosyldelphinidin, Al 3+ , and 5- O -acylquinic acid in a ratio 1:1:1 as determined by the electrospray ionization time-of-flight mass spectrometry and nuclear magnetic resonance spectra. To map the distribution of hydrangea blue-complex in sepal tissues, we carried out cryo-time-of-flight secondary ion mass spectrometry analysis. The spectrum of the reproduced hydrangea blue-complex with negative mode-detection gave a molecular ion at m/z = 841, which was consistent with the results of ESI-TOF MS. The same molecular ion peak at m/z = 841 was detected in freeze-fixed blue sepal-tissue. In sepal tissues, the blue cells were located in the second layer and the mass spectrometry imaging of the ion attributable to hydrangea blue-complex overlapped with the same area of the blue cells. In colorless epidermal cells, atomic ion of Al 3+ was hardly detected and potassium adduct ion of 5- O -caffeoyl and/or 3- O -acylquinic acid were found. This is the first report about the distribution of aluminum, potassium, hydrangea blue-complex, and copigment in sepal tissues and the first evidence that aluminum and hydrangea blue-complex exist in blue sepal cells and are involved in blue coloration.

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“…The co-pigments 5CQ ( 2 ) and 5 p CQ ( 3 ) were synthesized [17,22], and 3CQ ( 2 ) was purchased from WAKO. Formate buffer (pH 3.2) was prepared by mixing 5 mM formic acid (diluting of 88% Formic acid, WAKO, Osaka, Japan) and 5 mM sodium formate (dissolving of sodium formate, WAKO).…”

Section: Methodsmentioning

confidence: 99%

Direct Observation of Hydrangea Blue-Complex Composed of 3-O-Glucosyldelphinidin, Al3+ and 5-O-Acylquinic Acid by ESI-Mass Spectrometry

2018

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The blue sepal color of hydrangea is due to a metal complex anthocyanin composed of 3-O-glucosyldelphinidin (1) and an aluminum ion with the co-pigments 5-O-caffeoylquinic acid (2) and/or 5-O-p-coumaroylquinic acid (3). The three components, namely anthocyanin, Al3+ and 5-O-acylquinic acids, are essential for blue color development, but the complex is unstable and only exists in an aqueous solution. Furthermore, the complex did not give analyzable NMR spectra or crystals. Therefore, many trials to determine the detailed chemical structure of the hydrangea-blue complex have not been successful to date. Instead, via experiments mixing 1, Al3+ and 2 or 3 in a buffered solution at pH 4.0, we obtained the same blue solution derived from the sepals. However, the ratio was not stoichiometric but fluctuated. To determine the composition of the complex, we tried direct observation of the molecular ion of the complex using electrospray-ionization mass spectrometry. In a very low-concentration buffer solution (2.0 mM) at pH 4.0, we reproduced the hydrangea-blue color by mixing 1, 2 and Al3+ in ratios of 1:1:1, 1:2:1 and 1:3:1. All solution gave the same molecular ion peak at m/z = 843, indicating that the blue solution has a ratio of 1:1:1 for the complex. By using 3, the observed mass number was m/z = 827 and the ratio of 1, 3 and Al3+ was also 1:1:1. A mixture of 1, 3-O-caffeoylquinic acid (4) and Al3+ did not give any blue color but instead was purple, and the intensity of the molecular ion peak at m/z = 843 was very low. These results strongly indicate that the hydrangea blue-complex is composed of a ratio of 1:1:1 for 1, Al3+ and 2 or 3.

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Efficient and versatile synthesis of 5-O-acylquinic acids with a direct esterification using a p-methoxybenzyl quinate as a key intermediate

Cited by 10 publications

References 79 publications

Metal Complex Pigment Involved in the Blue Sepal Color Development of Hydrangea

Metal Complex Pigment Involved in the Blue Sepal Color Development of Hydrangea

Direct mapping of hydrangea blue-complex in sepal tissues of Hydrangea macrophylla

Direct Observation of Hydrangea Blue-Complex Composed of 3-O-Glucosyldelphinidin, Al3+ and 5-O-Acylquinic Acid by ESI-Mass Spectrometry

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