- Efficient and versatile synthesis of 5-O-acylquinic acids with a direct esterification using a p-methoxybenzyl quinate as a key intermediate
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An efficient and versatile synthesis of 5-O-acylquinic acids from commercially available (-)-quinic acid was accomplished. We designed p-methoxybenzyl quinate as a key intermediate, and two problems, the esterification of the sterically hindered 5-OH group for the concise divergent synthesis and the low yield of the final deprotection step, were solved. For the first problem, we improved Tanabe's method, TsCl/NMI-mediated esterification using free carboxylic acids, by the addition of i-Pr2NEt. For the second problem, we established a TFA- or BCl3/C6HMe5-catalyzed deprotection reaction for the final deprotection step. 5-O-Acylquinic acids were synthesized in seven steps with 45-60% overall yield.
- Oyama, Kin-Ichi,Watanabe, Noriyuki,Yamada, Tomomi,Suzuki, Masako,Sekiguchi, Yukiko,Kondo, Tadao,Yoshida, Kumi
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p. 3120 - 3130
(2015/05/04)
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- Total synthesis of Enantiopure potassium aeshynomate
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Potassium aeshynomate (1) is the leaf-opening factor of the nyctinastic plant Aeshynomene indica L. In this article a convenient and efficient strategy for the total synthesis of enantiomerically pure 1 is described, starting from the l-arabinose derived
- Rizos, Stergios R.,Stefanakis, John G.,Kotoulas, Stefanos S.,Koumbis, Alexandros E.
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p. 6646 - 6654
(2014/08/05)
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- Synthesis of two alnustone-like natural diarylheptanoids via 4+3 strategy
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The first total synthesis of (4E,6E)-1,7-bis(3,4-dihydroxyphenyl)-hepta-4, 6-dien-3-one and an alternative synthesis of (4E,6E)-1,7-bis(4-hydroxyphenyl)- hepta-4,6-dien-3-one, two natural diarylheptanoids, mainly based on Claisen-Schmidt condensation were described. The crucial steps of the syntheses were the condensation of OH-protected 4-aryl-2-butanones with OH-protected 3-aryl-acrylaldehydes by the in situ enamination and then deprotection of OH groups to give the corresponding natural diarylheptanoids. Copyright Taylor & Francis Group, LLC.
- Burmaoglu, Serdar,Celik, Huelya,Goeiksu, Sueleyman,Maras, Ahmet,Altundas, Ramazan,Secen, Hasan
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experimental part
p. 1549 - 1562
(2009/11/30)
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- Enantioselective synthesis of (2R,3S)-(+)-catechin
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A new enantioselective synthetic method for catechin from trans-methyl cinnamate derivative was developed via asymmetric dihydroxylation (ADH), the addition of an aryllithium species, followed by the Barton-McCombie reaction and an intramolecular Mitsunobu reaction as key steps.
- Jew, Sang-sup,Lim, Doo-yeon,Bae, So-young,Kim, Hyun-ah,Kim, Jeong-hoon,Lee, Jihye,Park, Hyeung-geun
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p. 715 - 720
(2007/10/03)
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