Dinemasones A, B and C – New Bioactive Metabolites from the Endophytic Fungus <i>Dinemasporium strigosum</i>

Krohn, Karsten; Sohrab, Md. Hossain; Ree, Teunis van; Draeger, Siegfried; Schulz, Barbara; Antus, Sándor; Kurtán, Tibor

doi:10.1002/ejoc.200800688

Cited by 31 publications

(24 citation statements)

References 20 publications

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“…Secondly, the carbonyl signal in the 13 C NMR spectrum of compound 1a for C-3 (δ = 166.0 ppm) was missing, and instead a methylene signal was observed at δ = 65.9 (C-3) ppm in 2, confirmed by the appearance of two signals for methylene protons at C-3 (δ = 4.33 and 3.95 ppm) in the 1 H NMR spectrum. The planar structure of 2 shown in Figure 1 was also in agreement with the entire set of 1 were very close to those observed for 1a. These data demonstrated that 1a-H and 7a-H are cis as required for epoxide protons, and the hydroxy group should be oriented trans to the epoxide moiety as in 1a (Figure 1).…”

Section: Resultssupporting

confidence: 87%

New Bioactive 2,3‐Epoxycyclohexenes and Isocoumarins from the Endophytic Fungus Phomopsis sp. from Laurus Azorica

et al. 2009

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Six new metabolites, namely cycloepoxylactone (1a), cycloepoxytriol A (2), cycloepoxytriol B (3) and phomolactones A–C (4–6), were isolated from two cultures of the ethyl acetate soluble fraction of the endophytic fungus Phomopsis sp. (internal strain no. 7233). Their structures were determined by means of spectroscopic data including HREIMS, 1H NMR, 13C NMR, and 2D NMR (HMQC, HMBC, and NOESY). The absolute configurations of 1a, 4 and 5 were determined by circular dichroism and comparison of solution CD spectra with TDDFT‐calculated ones. Preliminary studies showed that cycloepoxylactone (1a) has good antibacterial, antifungal, and algicidal activity against Bacillus megaterium, Microbotryum violaceum, and Chlorella fusca, respectively, whereas cycloepoxytriol B (3) has good algicidal activity against Chlorella fusca.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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Section: Resultssupporting

confidence: 87%

New Bioactive 2,3‐Epoxycyclohexenes and Isocoumarins from the Endophytic Fungus Phomopsis sp. from Laurus Azorica

et al. 2009

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“…Dinemasones A-C (54-56) were isolated from Dinemasporium strigosum associated to roots of Calystegia sepium [97], with promising antifungal, antibacterial, and antialgal activities. The dimeric compounds pestalotines A and B (A: 57) were isolated from an endophytic Pestalotiopsis sp.…”

Section: Oxo-bridged Polycyclic Polyketidesmentioning

confidence: 99%

Diversity and Ecological Significance of Fungal Endophyte Natural Products

Prado¹,

Li²,

Nay³

2012

Bioactive Natural Products

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“…Krohn characterized dinemasone C ( 2 ) by conversion of a mixture of dinemasones B ( 1 ) and C ( 2 ) to the diacetates with Ac 2 O, pyridine, and DMAP in low yield 1. Under these conditions, we found that the major product from 2 was anhydrodinemasone BC acetate ( 25 ), which was presumably formed by elimination of acetate from the enolate of the desired diacetate 27 .…”

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“…1 The major isomer, dinemasone B ( 1 ), is active against the Gram-positive bacterium Bacillus megaterium , the fungus Microbotryum violaceum and the alga Chlorella fusca . The minor isomer, dinemasone C ( 2 ), was characterized as a mixture of dinemasone B and C diacetates and was therefore not tested for biological activity.…”

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Synthesis and Biological Evaluation of (±)-Dinemasone C and Analogues

et al. 2010

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Dinemasone C was prepared in three steps (8% overall yield) from cis-tetrahydro-4-hydroxy-6-methyl-2-pyrone by aldol reaction with 2,4-hexadienal, epoxidation followed by cyclization, and epimerization of the ring fusion. Dinemasone C, epi-dinemasone C, anhydrodinemasone BC, and nor-dinemasone B are active against bacteria, including Legionella pneumophila Corby, algae, and fungi.Krohn and co-workers recently isolated dinemasones B (1) and C (2) from a culture of the endophytic fungus Dinemasporium strigosum, which was isolated from the roots of Calystegia sepium (see Figure 1).1 The major isomer, dinemasone B (1), is active against the Gram-positive bacterium Bacillus megaterium, the fungus Microbotryum violaceum and the alga Chlorella fusca. The minor isomer, dinemasone C (2), was characterized as a mixture of dinemasone B and C diacetates and was therefore not tested for biological activity. The structure of 1 is similar to that of the moderately biologically active fusidilactone B (3), which differs in the size of the lactone ring, the side chain, and the absolute stereochemistry, and was previously isolated by Krohn and co-workers from an endophytic fungus Fusidium sp.2 Other members of this family include TAN-2483A (4) with strong c-src kinase inhibitory action, which was isolated by a Takeda Chemical Industries group from the filamentous fungus NF 2329,3 and waol-A (5) with broad spectrum anti-tumor activity, which was isolated by Mizoue and co-workers from another fungus Myceliophthora lutea TF-0409.4We recently reported short, efficient syntheses of TAN-2483A (4), waol-A (5), and the ring system of fusidilactone B (3).5 In the latter synthesis, we converted hydroxy lactone 6 to the dianion with LDA at −42 °C and treated it with 2,4-hexadienal (7) to give aldol adducts 8 (36%) and 9 (31%) (see Scheme 1). The major adduct 8 was subjected to iodoetherification with iodine and bis(sym-collidine)AgPF 6 to give iodo alcohol 10 in 91% yield. Radical snider@brandeis.edu. Supporting Information Available: Additional experimental procedures and copies of 1 H and 13 C NMR spectral data. This material is available free of charge via the Internet at http://pubs.acs.org. Acetonide 13 is a protected version of nor-dinemasone B (14), which differs from dinemasone B (1) only by the absence of a methylene group in the lactone ring. Since the route to 13 is very short, we decided to prepare 14 for evaluation of its biological activity. Attempted epimerization of 11 without protection of the diol using DBN in CH 2 Cl 2 at 0 °C gave a complex mixture containing little 14.6 Therefore acetonide 13 was hydrolyzed with 4:1 HOAc:H 2 O to give nor-dinemasone B (14) in 84% yield NIH Public AccessWe tried to apply this chemistry to the synthesis of dinemasones B (1) and C (2) starting with δ-lactone 157 rather than γ-lactone 6 (see Scheme 2). Conversion of 15 to the dianion with LDA at −78 °C and treatment with 2,4-hexadienal (7) afforded a difficultly separable 1:2 mixture of aldol adducts 16 and 17 in 44% yield. The 9.2 H...

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Dinemasones A, B and C – New Bioactive Metabolites from the Endophytic Fungus Dinemasporium strigosum

Cited by 31 publications

References 20 publications

New Bioactive 2,3‐Epoxycyclohexenes and Isocoumarins from the Endophytic Fungus Phomopsis sp. from Laurus Azorica

New Bioactive 2,3‐Epoxycyclohexenes and Isocoumarins from the Endophytic Fungus Phomopsis sp. from Laurus Azorica

Diversity and Ecological Significance of Fungal Endophyte Natural Products

Synthesis and Biological Evaluation of (±)-Dinemasone C and Analogues

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