Stoffwechselprodukte von Mikroorganismen, 172. Isolierung des Antibioticums semi‐Vioxanthin aus Penicillium citreo‐viride und Synthese des Xanthomegnins

Zeeck, Axel; Russ, P.; Laatsch, Hartmut; Loeffler, W.; Wehrle, Herbert; Zähner, Hans; Holst, H.

doi:10.1002/cber.19791120319

Cited by 57 publications

(35 citation statements)

References 34 publications

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“…Hence monoacetylhaem oventosin is assigned the /w fl-quinonoid structure 4. H-8 is deshielded in 14 compared to 4 and the chemical shift (dH 6.85) is the same as in 13 [10]. Haemoventosin has a centre of chirality at C-3 and should be optically active.…”

Section: Resultsmentioning

confidence: 86%

“…One would expect the hydrogen bond in the indene ring system to be weaker than that in the naphthalene system; the closest analogues we Brought to you by | University of Glasgow Library Authenticated Download Date | 4/7/17 12:01 PM could find were related to dengibsin 10 [9], a de rivative of l-hydroxy-9-fluorenone, where the chemical shift of the hydrogen-bonded phenolic proton is always close to 6H 9. The hydroxyl pro ton chemical shift in monoacetylhaemoventosin (c>H 12.5) suggests the presence of a much stronger hydrogen bond than in 10 and indeed (3H of a perihydrogen-bonded hydroxyl proton is typically around 13 ppm in naphthoquinones [10,11].…”

Section: Resultsmentioning

confidence: 98%

“…The ques tion of deciding between the para-and ortho-quinonoid nature of structures 4 and 7 was resolved by noting that dithionite reduction [10] of 10-0-acetyl-sem/-xanthomegnin 11 did not produce the expected hydroquinone 12 but rather 13. in which transesterification had occurred to produce a hy droxyl group strongly hydrogen-bonded (c>H 13.04) to the lactone carbonyl group. In the case of struc ture 4 similar behaviour might be expected to pro duce 14 (with a strongly dishielded hydroxyl pro ton) whereas in the reduction of structure 7 it would not be possible for intramolecular transes terification to occur and the product 15 would not show any strongly deshielded hydroxyl protons.…”

Section: Resultsmentioning

confidence: 99%

“…It is noteworthy that Bruun and Lamvik [1] gave few details of the 'H NMR spectrum of monoacetylhaemoventosin; similarly Zeeck et al [10] did not report any 'H NM R data for 10-0-acetyl-sw?/-xanthomegnin 11, which might be expected to dis play similar conform ational behaviour to 4, and similar complications in the NMR spectra.…”

Section: Conformation Isomerismmentioning

confidence: 95%

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Revised Structure of Haemoventosin

Rycroft

Connolly

Huneck

et al. 1995

Zeitschrift Für Naturforschung B

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Section: Resultsmentioning

confidence: 86%

Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Section: Conformation Isomerismmentioning

confidence: 95%

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Revised Structure of Haemoventosin

Rycroft

Connolly

Huneck

et al. 1995

Zeitschrift Für Naturforschung B

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“…The IR spectrum showed absorptions for hydroxyl (3300 cm Ϫ1 ) and carbonyl groups (1680, 1620 cm Ϫ1 ) indicating a para-quinone system. 9,10) The complete structure of 1 was elucidated by 1D and 2D NMR experiments at 500 MHz. .…”

Section: Resultsmentioning

confidence: 99%

A New Cytotoxic Naphthoquinone from Paepalanthus latipes.

et al. 2005

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Quinones are widely distributed in nature and constitute an important class of naturally occurring compounds. They are found in plants, fungi and bacteria. 1) These compounds are aromatic rings with two ketone substitutions. 2) Large number of quinones has been associated with antitumor, antibacterial, antimalarial and antifungal activities.3) The antitumor activity is exhibited predominantly by three main groups of naturally occurring quinones such as benzoquinone, naphthoquinone and anthraquinone. Mitomycin and streptonigrin possess p-benzoquinone moiety with heterocyclic groups whereas anthracyclines, doxorubicin and daunorubicin consist of anthraquinone moiety. Some naphthaquinone antibiotics such as lapachol and lapinone are also found to be cytotoxic to tumor cells. 4) Plants of the Eriocaulaceae family are widespread in the region of the Serra do Cipó, State Minas Gerais, Brazil. Several plants from this family are known as 'everlasting plants' because they appear to be alive even for years after being haversted. Paepalanthus is the largest genus of this family with approximately 500 species. Among there more than 400 species are endemic in Brazil. 5) In previous works we have described some biological activity (cytotoxicity, antimicrobial and antioxidant) from naphthopyrones isolated from the capitula of P. bromelioides. [6][7][8] In this work we describe the isolation, structure determination and the cytotoxic effect in vitro of a new 1,4-naphthoquinone isolated from the capitula of Paepalanthus latipes. Results and DiscussionCompound 1 was obtained as a red powder. The ES-MS spectrum of 1 (positive mode) exhibited protonated molecular ion [MϩH] ] ϩ were also observed. The IR spectrum showed absorptions for hydroxyl (3300 cm Ϫ1 ) and carbonyl groups (1680, 1620 cm Ϫ1 ) indicating a para-quinone system. 9,10) The complete structure of 1 was elucidated by 1D and 2D NMR experiments at 500 MHz. The 13 C-NMR spectrum showed 16 signals. The 1 H-NMR spectrum displayed singlets of aromatic protons at d 6.60 (1H) and 6.05 (1H). Also evident were signals at d 3.86 and 3.81 typical of aromatic methoxyl groups. Another signal at d 2.28 (3H) corresponds to a methyl group. Assignments of 1 H-and 13 C-NMR data were based on HMBC and HSQC experiments (Table 1). In the HMBC spectrum we observed diagnostic long-range correlations between the proton signal at d 6.60 (H-4) and the carbon resonances at d 167.0 (C-1), 161.4 (C-10), 113.0 (C-10a), 148.0 (C-5) and 20.3 (C-11); the proton at d 6.08 (H-8) and the carbonyl carbon resonances at d 177.9 (C-6) and at d 189.2 (C-9) and the carbon resonances at 160.9 (C-7) and 111.2 (C-9a); the proton at d 3.86 (OCH 3 -7) and the carbon resonance at d 160.9 (C-7); the proton signal at d 3.81 (OCH 3 -5) and the carbon resonance at d 147.9 (C-5); the methyl group at d 2.28 (CH 3 -11) and the carbon signals at d 160.7 (C-3) and d 98.2 (C-4). NOESY experiment displayed correlations between the signal at d 6.60 (H-4) and the signals at d 2.28 (CH 3 -11) and at d 3.81 (OCH 3 -5), and betw...

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