- 7-O-Acetyl loganic acid from Alangium platanifolium var. Trilobum
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7-O-Acetyl loganic acid was isolated for the first time in Nature from the stem bark of Alangium platanifolium var. trilobum.
- Nakamoto, Kyoumi,Otsuka, Hideaki,Yamasaki, Kazuo
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- Iridoids from Symphoricarpos albus
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Twelve compounds including secologanin, loganin, the aglycon of loganin, and a new iridoid called glucologanin were isolated from fruit of common snowberry Symphoricarpos albus (L.) Blake. The structure of glucologanin was confirmed using PMR and mass spe
- Makarevich,Kovalenko,Gusarova,Gubin
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experimental part
p. 40 - 44
(2009/06/20)
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- Iridoids, XXII. - Glucosidation of Hemiacetals. - Highly Stereoselective Synthesis of Iridoid Glucosides
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Reaction of the racemic iridoid aglucone acetates 9d-12d with the trimethylsilyl β-glucopyranoside 4a in the presence of catalytic amounts of trimethylsilyl trifluoromethanesulfonate (7) in acetonitrile or liquid sulfur dioxide at -30 deg C and -50 deg C, respectively, followed by solvolysis gives in excellent yields nearly exclusively the β-glucosides 9g and 11g.Glucosidation of the enantiomerically pure acetates 9d/10d affords the β-glucoside 9g.In a similar way, the biosynthetical key intermediate loganin (1) is obtained from 16a in 60 percent yield.
- Tietze, Lutz F.,Fischer, Roland,Remberg, Gerd
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p. 971 - 976
(2007/10/02)
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- Reductive, Radical-Induced Cyclizations of 5-Hexenals as a Biomimetic Model of the Chemistry of Secologanin Formation
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A model reaction for studying the mechanism of the biological conversion of the iridoid loganin (1) to the secoiridoid secologanin (2) is the reductive, radical-induced cyclization of secologanin tetraacetate (4) to loganin tetraacetate.Treatment of 4 with Mg and Me3SiCl in THF at room temperature gives a mixture of the four possible C-6 and C-7 epimers of loganin tetraacetate in which the natural stereochemistry predominates.This result suggests that the biochemical event, which involves cleavage of the C-6 and C-7 bond of 1 in forming 2, may be a homolytic process that is initiated by formation of a carbon radical at C-8.The scope of the cyclization reaction, which formally occurred in a 5-hexanal moiety in 4, is defined by studies of the cyclization of six other δ,ε-unsaturated aldehydes.The results illustrate a new way for ring annulation through the reductive, radical-induced cyclization of δ,ε-unsaturated aldehydes.
- Ikeda, Takafumi,Yue, Stephen,Hutchinson, C. Richard
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p. 5193 - 5199
(2007/10/02)
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- IRIDOID GLUCOSIDES FROM CAMPSIS CHINENSIS
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Two new iridoid glucosides, 5-hydroxycampenoside and cachineside I, were isolated together with tecomoside from leaves of Campsis chinensis and their structures were elucidated.The absolute stereochemistry of 5-hydroxycampenoside has been established by X-ray analysis, and the structural correlation between 5-hydroxycampenoside and tecomoside has been determined by spectral and chemical experiments. - Key Word Index: Campsis chinensis; Bignoniaceae; iridoid glucosides; 5-hydroxycampenoside; tecomoside; cachineside I; X-ray structure.
- Imakura, Yasuhiro,Kobayashi, Shigeru,Kida, Kiyoshi,Kido, Masaru
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p. 2263 - 2270
(2007/10/02)
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- 245. Studies on Monoterpene Glucosides and Related Natural Products. Part 51. Absolute Structures of Hydrangenosides A, B, C, D, E, F, and G. Novel Type Secoiridoid Glucosides from Two Hydrangea Plants
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From Hydrangea macrophylla var. macrophylla, four new secoiridoid glucosides, hydrangenosides A, B, C and D, were isolated, along with the known iridoid glucosides loganin, secologanin, secologanic acid and sweroside.Moreover, hydrangenosides E, F, and G,
- Uesato, Shinici,Takeda, Yoshio,Hashimoto, Toshihiro,Uobe, Kenichi,Inouye, Hiroyuki,et al.
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p. 2111 - 2127
(2007/10/02)
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- NEW IRIDOID GLUCOSIDES, CAMPENOSIDE AND 5-HYDROXYCAMPENOSIDE, FROM CAMPSIS CHINENSIS VOSS
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Two novel iridoid glucosides, campenoside and 5-hydroxycampenoside were isolated from the leaves of Campsis chinensis Voss and their structures were shown to be 2 and 3, respectively.
- Kobayashi, Shigeru,Imakura, Yasuhiro,Yamahara, Yoshinobu,Shingu, Tetsuro
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p. 1475 - 1478
(2007/10/02)
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