Isolation of rhododaurichromanic acid B and the anti-HIV principles rhododaurichromanic acid A and rhododaurichromenic acid from Rhododendron dauricum

Kashiwada, Yoshiki; Yamazaki, Kimihisa; Ikeshiro, Yasumasa; Yamagishi, Takashi; Fujioka, Toshihiro; Mihashi, Kunihide; Mizuki, Koichi; Cosentino, L. Mark; Fowke, Keith R.; Morris‐Natschke, Susan L.; Lee, Kuo Hsiung̀

doi:10.1016/s0040-4020(00)01144-3

Cited by 213 publications

(162 citation statements)

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“…Important biological activities have been reported for 2,2-disubstituted chiral chromanes: Vitamin E (1) [1] with lipophilic antioxidant activity, trans-δ-tocotrienoloic acid (2) [2] with antibacterial activity, rhododaurichromanic acid A (3) [3] with anti-HIV effects, and siccanin (4) [4] with strong antifungal activity ( Figure 1). The enantioselective synthesis of 2,2-disubstituted chromane skeletons, for the purpose of further therapeutic modification, is an important issue in the synthesis of these important natural products.…”

Section: Introductionmentioning

confidence: 99%

Guanidine‐Catalyzed Asymmetric Synthesis of 2,2‐Disubstituted Chromane Skeletons by Intramolecular Oxa‐Michael Addition

et al. 2008

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The guanidine-catalyzed 6-exo-trig-type intramolecular asymmetric oxa-Michael addition of α,β-unsaturated esters with a 2-hydroxyaryl moiety at the C-5 carbon has been examined for the construction of chromane skeletons with a quaternary carbon chiral center. The bulkiness of the alkyl group and the E/Z geometry of the α,β-unsaturated ester function played important roles in the asymmetric induction and (4S,5S)-2-[(R)-1-hydroxymethyl-2-phenylethylimino]-

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Section: Introductionmentioning

confidence: 99%

Guanidine‐Catalyzed Asymmetric Synthesis of 2,2‐Disubstituted Chromane Skeletons by Intramolecular Oxa‐Michael Addition

et al. 2008

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“…[49] We envisioned that by using 1,3-diketones (Scheme 21), this formal cycloaddition strategy could provide a unique approach to 1-oxadecalins and oxa-spirocycles that are well represented in biologically relevant natural products such as phomactin A (100), [50,51] penostatin A (101), [52] and rhododaurichromanic acid A (102). [53] Scheme 21 As we pursued this methodology, [15,54] we realized that de Groot, [48] Tietze, [55] and Schuda, [56] had already laid down some strong foundations. As briefly summarized in Scheme 22, de Groot and Jansen, who completed a total synthesis of flindersane from 4-hydroxy-2-quinolone, [48] also reported a series of reactions exemplified by boiling 1,3-cyclohexanedione 103 with enal 104 in pyridine to give 1-oxadecalinone 105 in 82% yield.…”

Section: Chromanoids and Chromenoidsmentioning

confidence: 99%

“…Rhododaurichromanic acids A and B (111a and 111b) can be isolated [60] from rhododendron dauricum, [61] a plant native to areas of northern China, east Siberia, and Hokkaido, Japan (Scheme 23). A known natural product, daurichromenic acid (112a), was also isolated during the same study.…”

Section: Chromanoids and Chromenoidsmentioning

confidence: 99%

A Formal [3 + 3] Cycloaddition Approach to Natural‐Product Synthesis

2004

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A formal [3 + 3] cycloaddition strategy for constructing complex heterocycles is reviewed here. This formal cycloaddition involves condensation of α,β-unsaturated iminium salts with 1,3-dicarbonyl equivalents. These reactions consist of a Knoevenagel-type condensation followed by a reversible 6π-electron electrocyclic ring-closure. They constitute a stepwise formal [3 + 3] cycloaddition protocol with the net result being the formation of two σ-bonds in addition to a new ste-

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“…Previously, (+)-daurichromenic acid (9) was reported to show highly potent anti-HIV activity with a 50% effective concentration value of 0.00567 µg mL −1 . 31 However, other compounds were devoid of anti-HIV activity ( Table 1).…”

Section: Introductionmentioning

confidence: 99%

Inedible mushrooms: a good source of biologically active substances

2006

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ABSTRACT:In the course of our investigation on biologically active substances from inedible mushrooms in Japan, Germany, and Vietnam, we studied the chemical constituents of 22 species belonging to five families: Scutigeraceae, Polyporaceae, Xylariaceae, Thelephoraceae, and Paxillaceae. Various types of chemical substances were purified and characterized based on the modern spectroscopic methods and also on chemical reactions. These metabolites have shown a broad activity in many biological systems, such as antimicrobial, nematicidal, inhibition of NO production, antihuman immunodeficiency virus, tumor necrosis factor-α, and antioxidant activities. These isolated metabolites did not only show interesting activities, but also are employed as chemical markers supported for chemosystematics of these families. This review paper deals with the chemical constituents of 22 species, their biological activities, and also a discussion on chemosystematics.

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Isolation of rhododaurichromanic acid B and the anti-HIV principles rhododaurichromanic acid A and rhododaurichromenic acid from Rhododendron dauricum

Cited by 213 publications

References 1 publication

Guanidine‐Catalyzed Asymmetric Synthesis of 2,2‐Disubstituted Chromane Skeletons by Intramolecular Oxa‐Michael Addition

Guanidine‐Catalyzed Asymmetric Synthesis of 2,2‐Disubstituted Chromane Skeletons by Intramolecular Oxa‐Michael Addition

A Formal [3 + 3] Cycloaddition Approach to Natural‐Product Synthesis

Inedible mushrooms: a good source of biologically active substances

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