An efficient regioselective synthesis of endocrocin and structural related natural anthraquinones starting from emodin

Waser, Mario; Lackner, Bernd; Zuschrader, Joachim; Müller, Norbert; Falk, Heinz

doi:10.1016/j.tetlet.2005.02.061

Cited by 22 publications

(14 citation statements)

References 13 publications

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“…Unfortunately, these 7‐functionalized emodin derivatives turned out to be not suitable for the syntheses of 6,7‐bifunctional emodin derivatives due to their unsubstituted methyl group at C(6). The activation of this methyl group towards further oxidation seems to be rather hampered as a result of the additional electron‐withdrawing functional groups at C(7) as observed in our synthesis of endocrocin6 as well as by Joshi et al in their endocrocin synthesis starting from 6,7‐dimethyl emodin, where only the 7‐methyl group could be oxidized 9…”

Section: Resultsmentioning

confidence: 61%

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Condensed Emodin Derivatives and Their Applicability for the Synthesis of a Fused Heterocyclic Hypericin Derivative

Waser

Falk

2006

Eur J Org Chem

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Investigations on the bifunctionalization of emodin at C(6) and C(7) with respect to the synthesis of a new class of fused heterocyclic hypericin derivatives were undertaken. The synthesis of such complex anthraquinone derivatives is possible by applying a Marschalk‐type reaction with emodin‐6‐carbaldehyde as the key step. The newly synthesized pyridazinone‐fused hypericin derivative possesses a satisfying bathochromically shifted absorption maximum making it a promising candidate for further investigations concerning a possible application in photodynamic therapy. Furthermore, the herein described strategy for the bifunctionalization of emodin provides a novel route for the synthesis of anthraquinone derivatives that are difficult to obtain by other methods.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

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Section: Resultsmentioning

confidence: 61%

“…We have recently described the regioselective functionalization of the emodin moiety at C(7)6 via a Marschalk‐type approach 7. This methodology provides a useful tool for the regioselective hydroxymethylenation of hydroxy‐anthraquinones.…”

Section: Resultsmentioning

confidence: 99%

Condensed Emodin Derivatives and Their Applicability for the Synthesis of a Fused Heterocyclic Hypericin Derivative

Waser

Falk

2006

Eur J Org Chem

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“…Compounds 1-8 (l "Fig. 1) were identified using mass spectrometry and 1 H-and 13 C-NMR experiments, and by comparison of their spectral data with that reported in the literature as chrysophanol (1)[16], physcion (2)[16], emodin (3)[16], emodin-8-Oβ-D-glucopyranoside (5)[17], endocrocin (6)[18], and nepodin (7)[19]. Nepodin was reported earlier as musizin; however, the compounds are structurally identical[20,21].…”

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confidence: 99%

Anti-inflammatory, Cyclooxygenase (COX)-2, COX-1 Inhibitory, and Free Radical Scavenging Effects ofRumex nepalensis

et al. 2010

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Evaluation of the topical anti-inflammatory activity of chloroform and ethyl acetate extracts of RUMEX NEPALENSIS roots in a TPA-induced acute inflammation mouse model demonstrated a significant reduction in ear edema. The extracts were further tested on purified enzymes for COX-1 and COX-2 inhibition to elucidate their mechanism of action, and a strong inhibition was observed. Six anthraquinones and two naphthalene derivatives were isolated from the ethyl acetate extract. Among the isolated compounds, emodin was found to be a potent inhibitor with slight selectivity towards COX-2, and nepodin exhibited selectivity towards COX-1. Emodin, endocrocin, and nepodin also exhibited significant topical anti-inflammatory activity in mice. Interestingly, nepodin showed better radical scavenging activity than trolox and ascorbic acid against DPPH and ABTS radicals. The strong radical scavenging activity of chloroform and ethyl acetate extracts could be explained by the presence of nepodin as well as by the high phenolic content of the ethyl acetate extract. Thus, the anti-inflammatory effect of R. NEPALENSIS roots was assumed to be mediated through COX inhibition by anthraquinones and naphthalene derivatives and through the radical scavenging activities of naphthalene derivatives.

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“…Other known compounds were identified as 18-oxotryprostatin A ( 3 ) [ 22 ], sulochrin ( 5 ) [ 26 ], monomethylsulochrin ( 6 ) [ 23 ], 6-methoxyspirotryprostatin B ( 7 ) [ 22 ], spirotryprostatin A ( 8 ) [ 27 ], spirotryprostatin C ( 9 ) [ 28 ], pseurotin A ( 11 ) [ 25 ], azaspirofuran A ( 12 ) [ 29 ], demethoxyfumitremorgin C ( 13 ) [ 30 ], fumitremorgin C ( 14 ) [ 28 ], 13-oxofumitremorgin B ( 15 ) [ 31 ], fumitremorgin B ( 16 ) [ 28 ], verruculogen ( 17 ) [ 28 ], helvolinic acid ( 18 ) [ 32 ], helvolic acid ( 19 ) [ 33 ], fumiquinazolines J ( 20 ) [ 34 ], chaetominine ( 21 ) [ 35 ], fumigaclavine C ( 22 ) [ 36 ], 9-deacetylfumigaclavine C ( 23 ) [ 36 ], fumagiringillin ( 24 ) [ 37 ], asterric acid ( 25 ), circinophoric acid ( 26 ) [ 38 ], dimethyl 2,3′-dimethylosoate ( 27 ) [ 23 ], methylated asterric acid ( 28 ) [ 39 ], endocrocin ( 29 ) [ 40 ], and questin ( 30 ) [ 41 ]. Their 1 H and 13 C NMR data were identical to those reported in the literature.…”

Section: Resultsmentioning

confidence: 99%

Genome-Inspired Chemical Exploration of Marine Fungus Aspergillus fumigatus MF071

et al. 2020

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The marine-derived fungus Aspergillus fumigatus MF071, isolated from sediment collected from the Bohai Sea, China, yielded two new compounds 19S,20-epoxy-18-oxotryprostatin A (1) and 20-hydroxy-18-oxotryprostatin A (2), in addition to 28 known compounds (3–30). The chemical structures were established on the basis of 1D, 2D NMR and HRESIMS spectroscopic data. This is the first report on NMR data of monomethylsulochrin-4-sulphate (4) and pseurotin H (10) as naturally occurring compounds. Compounds 15, 16, 20, 23, and 30 displayed weak antibacterial activity (minimum inhibitory concentration: 100 μg/mL). Compounds 18 and 19 exhibited strong activity against S. aureus (minimum inhibitory concentration: 6.25 and 3.13 μg/mL, respectively) and E. coli (minimum inhibitory concentration: 6.25 and 3.13 μg/mL, respectively). A genomic data analysis revealed the putative biosynthetic gene clusters ftm for fumitremorgins, pso for pseurotins, fga for fumigaclavines, and hel for helvolinic acid. These putative biosynthetic gene clusters fundamentally underpinned the enzymatic and mechanistic function study for the biosynthesis of these compounds. The current study reported two new compounds and biosynthetic gene clusters of fumitremorgins, pseurotins, fumigaclavines and helvolinic acid from Aspergillus fumigatus MF071.

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An efficient regioselective synthesis of endocrocin and structural related natural anthraquinones starting from emodin

Cited by 22 publications

References 13 publications

Condensed Emodin Derivatives and Their Applicability for the Synthesis of a Fused Heterocyclic Hypericin Derivative

Condensed Emodin Derivatives and Their Applicability for the Synthesis of a Fused Heterocyclic Hypericin Derivative

Anti-inflammatory, Cyclooxygenase (COX)-2, COX-1 Inhibitory, and Free Radical Scavenging Effects ofRumex nepalensis

Genome-Inspired Chemical Exploration of Marine Fungus Aspergillus fumigatus MF071

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