Publications by authors named "Wolfgang Steglich"

29 Publications

  • Page 1 of 1

5-Hydroxymethyl-, 5-Formyl- and 5-Carboxydeoxycytidines as Oxidative Lesions and Epigenetic Marks.

Chemistry 2021 Mar 26. Epub 2021 Mar 26.

Ludwigs-Maximilian-Universität München, Butenandtstr. 5-13, 81377, Munich, Germany.

The four non-canonical nucleotides in the human genome 5-methyl-, 5-hydroxymethyl-, 5-formyl- and 5-carboxydeoxycytidine (mdC, hmdC, fdC and cadC) form a second layer of epigenetic information that contributes to the regulation of gene expression. Formation of the oxidized nucleotides hmdC, fdC and cadC requires oxidation of mdC by ten-eleven translocation (Tet) enzymes that require oxygen, Fe(II) and α-ketoglutarate as cosubstrates. Although these oxidized forms of mdC are widespread in mammalian genomes, experimental evidence for their presence in fungi and plants is ambiguous. This vagueness is caused by the fact that these oxidized mdC derivatives are also formed as oxidative lesions, resulting in unclear basal levels that are likely to have no epigenetic function. Here, we report the xdC levels in the fungus Amanita muscaria in comparison to murine embryonic stem cells (mESCs), HEK cells and induced pluripotent stem cells (iPSCs), to obtain information about the basal levels of hmdC, fdC and cadC as DNA lesions in the genome.
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http://dx.doi.org/10.1002/chem.202100551DOI Listing
March 2021

Enzymatic Formation of Rufoschweinitzin, a Binaphthalene from the Basidiomycete Cortinarius rufoolivaceus.

Chembiochem 2020 05 11;21(10):1423-1427. Epub 2020 Mar 11.

Institute of Pharmaceutical Sciences, Albert-Ludwigs-Universität Freiburg, Albertstrasse 25, 79104, Freiburg, Germany.

Dimeric polyketides are widespread fungal secondary metabolites. They occur in both ascomycetes and basidiomycetes and, therefore, across fungal phyla. Here we report the isolation of a new binaphthalene, named rufoschweinitzin, from the basidiomycete Cortinarius rufoolivaceus. Rufoschweinitzin consists of two symmetrically 4,4'-coupled torachrysone-8-O-methyl ether moieties. Furthermore, we have identified a binaphthalene biosynthetic gene cluster in an unrelated fungus, the ascomycete Xylaria schweinitzii. Heterologous expression of the encoded cytochrome P450 enzyme verified its coupling activity: dimerization of torachrysone-8-O-methyl ether led to the formation of rufoschweinitzin alongside a hitherto unknown regioisomer, now named alloschweinitzin. We have thus demonstrated enzymatic formation of the basidiomycete's metabolite rufoschweinitzin and made the regiochemistry of alloschweinitzin accessible with an ascomycete-derived enzyme.
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http://dx.doi.org/10.1002/cbic.201900742DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7384108PMC
May 2020

Mycenaflavin A, B, C, and D: Pyrroloquinoline Alkaloids from the Fruiting Bodies of the Mushroom Mycena haematopus.

Chemistry 2018 Jun 25;24(34):8609-8614. Epub 2018 May 25.

Institut für Organische und Analytische Chemie, Universität Bremen, Leobener Straße 7, 28359, Bremen, Germany.

Four so far unknown pyrroloquinoline alkaloids, yellow mycenaflavins A, B, and C, and the purple mycenaflavin D, have been isolated from the fruiting bodies of Mycena haematopus. The structures of these new alkaloids were elucidated by NMR spectroscopy and HRMS (ESI ). The mycenaflavins are structurally related to mycenarubins and haematopodins, which have been previously identified in M. haematopus. However, compared with other known fungal pyrroloquinoline alkaloids, the mycenaflavins contain an additional double bond within the pyrroloquinoline moiety that accounts for the yellow colour of the monomeric mycenaflavins A, B, and C. The purple mycenaflavin D is the first known dimeric pyrroloquinoline alkaloid with a C-C bridge between the two pyrroloquinoline units. Although the minor pyrroloquinoline alkaloid constituent mycenaflavin A exhibits only moderate bioactivity against the soil bacterium Azoarcus tolulyticus, the major pyrroloquinoline alkaloid constituent haematopodin B is similarly active as the antibiotic gentamicin.
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http://dx.doi.org/10.1002/chem.201800235DOI Listing
June 2018

Stereo specific platelet inhibition by the natural LXR agonist 22(R)-OH-cholesterol and its fluorescence labelling with preserved bioactivity and chiral handling in macrophages.

Biochem Pharmacol 2013 Jul 9;86(2):279-85. Epub 2013 May 9.

Institute for Cardiovascular Prevention, University of Munich, Pettenkoferstr. 9, 80336 Munich, Germany.

Two synthetic LXR agonists were recently reported to inhibit collagen-induced platelet aggregation and thrombus formation in mice. We therefore studied whether also natural LXR agonists inhibit human platelet activation and whether they can be fluorescence-labelled preserving their bioactivity for LXR-related functional imaging. The natural LXR agonist 22(R)-OH-cholesterol - but not its stereoisomer 22(S)-OH-cholesterol - inhibited collagen induced platelet shape change and aggregation similar to synthetic LXR agonists in a concentration- and time-dependent manner. First exposure to 22(S)-OH-cholesterol prevented the subsequent inhibition of platelets by 22(R)-OH-cholesterol but not vice versa. 22(R)- and 22(S)-OH-cholesterol could be fluorescence-labelled as 22(R)- and 22(S)-OH-cholesteryl-3-dodecanoic-3-BODIPY esters with high yield and purity using the Steglich acylation. Labelled 22(R)- and 22(S)-OH-cholesterol esters retained the stereo specific bioactivity of their parent compounds, were metabolically stable and not cytotoxic at LXR agonistic concentrations. Live staining with labelled 22(R)- or 22(S)-OH-cholesterol esters demonstrated stereo specific inhibition of platelet spreading and chiral handling by macrophages that reflect LXR activation. The rapid inhibition of platelet reactivity to collagen by natural and pharmacologic LXR agonists offers a mechanism that could attenuate platelet activation by denuded plaques that expose collagen and LXR agonistic oxysterols. Stable fluorescence labelled 22(R)- and 22(S)-OH-cholesterol analogues with preserved stereo specific bioactivity and staining characteristics provide valuable tools for LXR-related functional imaging in pathophysiologic studies, for binding assays and for LXR-targeted drug development.
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http://dx.doi.org/10.1016/j.bcp.2013.04.024DOI Listing
July 2013

Structure and absolute configuration of the fungal ansabenzoquinone rhizopogone.

J Nat Prod 2009 Feb;72(2):214-7

Department Chemie, Ludwig-Maximilians-Universitat Munchen, Butenandtstrasse 5-13, 81377 Munchen, Germany.

The main pigment of the basidiomycete Rhizopogon pumilionus is the [13]paracyclophane derivative rhizopogone (1). The structures of 1 and the accompanying 2-acetoxyrhizopogone (5) were determined by spectroscopic studies, including 1D and 2D NMR measurements. The absolute configuration of 1 was assigned by comparison of its CD spectrum with that of secotridentoquinone (4). The structures of 1 and tridentoquinone (3) suggest a common biosynthesis originating from 2-geranylgeranyl-6-hydroxy-1,4-benzoquinone (9). This supports the close taxonomic relationship of the genera Rhizopogon and Suillus (Boletales).
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http://dx.doi.org/10.1021/np8007073DOI Listing
February 2009

Vibralactone: a lipase inhibitor with an unusual fused beta-lactone produced by cultures of the basidiomycete Boreostereum vibrans.

Org Lett 2006 Dec;8(25):5749-52

State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, P.R. China.

The structure and absolute configuration of vibralactone (1) from the cultures of the Basidiomycete Boreostereum vibrans were established by spectroscopic methods and computational methods. Vibralactone, an unusual fused beta-lactone-type metabolite, was found to inhibit pancreatic lipase with an IC50 of 0.4 microg/mL. [structure: see text]
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http://dx.doi.org/10.1021/ol062307uDOI Listing
December 2006

Pityriarubins, novel highly selective inhibitors of respiratory burst from cultures of the yeast Malassezia furfur: comparison with the bisindolylmaleimide arcyriarubin A.

Chembiochem 2005 Dec;6(12):2290-7

Center of Andrology and Dermatology, Justus Liebig-Universität, Gaffkystrasse 14, 35385 Giessen, Germany.

Pityriasis versicolor is the most common skin mycosis in humans worldwide. Yeasts of the genus Malassezia, particularly M. furfur, a saprophyte occurring widely on human skin, are generally regarded as the causative agents. M. furfur is able to convert tryptophan into a variety of indole alkaloids, some of them showing biological properties that correlate well with certain clinical features of pityriasis versicolor. This suggests a possible role for these compounds in the pathophysiology of the disease. We here report that the novel pityriarubins A, B and C, isolated from cultures of the yeast, inhibit respiratory burst in human neutrophils, activated by various agents, in a highly selective, unexpected manner. The release of 5-lipoxygenase products after challenge of neutrophils with the calcium ionophore A23187 is also inhibited in a dose-dependent manner. These activities reflect the close structural relationship of pityriarubins to bisindolylmaleimides, which have recently gained great interest as protein kinase inhibitors.
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http://dx.doi.org/10.1002/cbic.200500163DOI Listing
December 2005

The DMAP-catalyzed acetylation of alcohols--a mechanistic study (DMAP = 4-(dimethylamino)pyridine).

Chemistry 2005 Aug;11(16):4751-7

Department Chemie und Biochemie, LMU München, Germany.

The acetylation of tert-butanol with acetic anhydride catalyzed by 4-(dimethylamino)pyridine (DMAP) has been studied at the Becke3 LYP/6-311 + G(d,p)//Becke3 LYP/6-31G(d) level of theory. Solvent effects have been estimated through single-point calculations with the PCM/UAHF solvation model. The energetically most favorable pathway proceeds through nucleophilic attack of DMAP at the anhydride carbonyl group and subsequent formation of the corresponding acetylpyridinium/acetate ion pair. Reaction of this ion pair with the alcohol substrate yields the final product, tert-butylacetate. The competing base-catalyzed reaction pathway can either proceed in a concerted or in a stepwise manner. In both cases the reaction barrier far exceeds that of the nucleophilic catalysis mechanism. The reaction mechanism has also been studied experimentally in dichloromethane through analysis of the reaction kinetics for the acetylation of cyclohexanol with acetic anhydride, in the presence of DMAP as catalyst and triethylamine as the auxiliary base. The reaction is found to be first-order with respect to acetic anhydride, cyclohexanol, and DMAP, and zero-order with respect to triethyl amine. Both the theoretical as well as the experimental studies strongly support the nucleophilic catalysis pathway.
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http://dx.doi.org/10.1002/chem.200500398DOI Listing
August 2005

Birnbaumin A and B: two unusual 1-hydroxyindole pigments from the "flower pot parasol" Leucocoprinus birnbaumii.

Angew Chem Int Ed Engl 2005 May;44(19):2957-9

Department Chemie, Ludwig-Maximilians-Universtät München, Butenandtstrasse 5-13, Haus F, 81377 München, Germany.

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http://dx.doi.org/10.1002/anie.200500082DOI Listing
May 2005

Malassezin, a novel agonist of the aryl hydrocarbon receptor from the yeast Malassezia furfur, induces apoptosis in primary human melanocytes.

Chembiochem 2005 May;6(5):860-5

Center of Andrology and Dermatology, Justus Liebig-Universität, Gaffkystrasse 14, 35385 Giessen, Germany.

Pityriasis versicolor is the most common skin mycosis in humans worldwide. Yeasts of the genus Malassezia, particularly M. furfur, a saprophyte occurring widely on human skin, are generally regarded as the causative agents. Pityriasis versicolor is often accompanied by a long-lasting depigmentation that persists even after successful antimycotic therapy. M. furfur is able to convert tryptophan into a variety of indole alkaloids, some of them showing biological properties that correlate well with certain clinical features of pityriasis versicolor. This suggests a possible role for these compounds in the depigmentation process. We now report that human melanocytes undergo apoptosis when exposed to the crude mixture of tryptophan metabolites from M. furfur. The active compound was identified as malassezin, previously isolated by us from the same source and characterized as an agonist of the aryl hydrocarbon (Ah) receptor. The compound could, therefore, contribute to the marked depigmentation observed during the course of pityriasis versicolor.
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http://dx.doi.org/10.1002/cbic.200400247DOI Listing
May 2005

A short diastereoselective synthesis of orthogonally protected diaminosuccinic acid derivatives.

J Org Chem 2004 Sep;69(18):6134-6

Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13 (Haus F), D-81377 München, Germany.

Homogeneous, Rh-catalyzed hydrogenation of heteromeric olefinic glycine dimers presents an efficient route to diastereomerically pure, orthogonally protected diaminosuccinic acid derivatives depending on the double bond geometry of the starting material. The products were obtained as racemates.
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http://dx.doi.org/10.1021/jo049371eDOI Listing
September 2004

Revision of the structures assigned to the fungal metabolites boletunones A and B.

Org Lett 2004 Sep;6(18):3175-7

Chemie Department, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13 (Haus F), D-81377 München, Germany.

[structure: see text] The structures recently assigned to the mushroom metabolites boletunones A (1) and B (2) are revised to those of 15-methoxycyclocalopin A (5) and isocyclocalopin A (6), respectively.
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http://dx.doi.org/10.1021/ol048724tDOI Listing
September 2004

Unusual pulvinic acid dimers from the common fungi Scleroderma citrinum (common earthball) and Chalciporus piperatus (peppery bolete).

Angew Chem Int Ed Engl 2004 Mar;43(14):1883-6

Department Chemie, Ludwig-Maximilians-Universität, Butenandtstrasse 5-13, Haus F, 81377 München, Germany.

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http://dx.doi.org/10.1002/anie.200352529DOI Listing
March 2004

Pityriarubins, biologically active bis(indolyl)spirans from cultures of the lipophilic yeast Malassezia furfur.

Angew Chem Int Ed Engl 2004 Feb;43(9):1098-100

Department Chemie, Ludwig-Maximilians-Universität, Butenandtstrasse 5-13, Haus F, 81377 München, Germany.

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http://dx.doi.org/10.1002/anie.200352549DOI Listing
February 2004

Lilacinone, a red aminobenzoquinone pigment from Lactarius lilacinus.

J Nat Prod 2003 Oct;66(10):1402-3

Department Chemie der Ludwig-Maximilians-Universität, Butenandtstrasse 5-13, D-81377 München, Germany.

A red pigment, lilacinone (1), was isolated from fruit bodies of the toadstool Lactarius lilacinus. Its structure was established by 2D NMR and APCIMS methods. Compound 1 is a novel type of fungal aminobenzoquinone pigment and may be biosynthetically derived from three molecules of anthranilic acid.
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http://dx.doi.org/10.1021/np0303052DOI Listing
October 2003

Pityrialactone- a new fluorochrome from the tryptophan metabolism of Malassezia furfur.

Antonie Van Leeuwenhoek 2003 ;84(3):185-91

Zentrum für Dermatologie und Andrologie, Justus Liebig Universität, Gaffkystr. 14, Giessen D-35385, Germany.

As the main nitrogen source in Malassezia (M.) furfur, tryptophan induces the formation of fluorochromes and pigments, which makes the yeast less sensitive towards UV light. For the investigation of the fluorochromes, M. furfur (CBS1878) was incubated at 32 degrees C for 14 days on a pigment-inducing medium, and the agar extract was purified by column chromatography, preparative TLC and HPLC. The structures of the pure metabolites were determined by mass spectrometry and NMR spectroscopy. A pale yellow compound eluting from the column with 22% acetonitrile was found to exhibit a strong green-yellow fluorescence. The fluorochrome is a new bisindolyl compound (C(20)H(12)N(2)O(3), MW 328.33) named pityrialactone because of its furan-2,3-dione structure. The UV protective properties (lambda(max) 352, 292, 276, 224 nm) of this metabolite were confirmed in a yeast model. As shown by the fluorescence spectrum, pityrialactone appears to be responsible for the green-yellow fluorescence of pityriasis versicolor lesions under Wood light. Pityrialactone is accompanied by the isomeric bisindolylmaleic anhydride (pityriaanhydride), which has not yet been described as a natural product but is a known intermediate in the total synthesis of bisindolylmaleimides.
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http://dx.doi.org/10.1023/a:1026042903354DOI Listing
February 2004

Enhancing the catalytic activity of 4-(dialkylamino)pyridines by conformational fixation.

Angew Chem Int Ed Engl 2003 Oct;42(39):4826-8

Department Chemie, Ludwig-Maximilians-Universität Munich, Butenandtstrasse 5-13, 81377 Munich, Germany.

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http://dx.doi.org/10.1002/anie.200352289DOI Listing
October 2003

Occurrence of the fungal toxin orellanine as a diglucoside and investigation of its biosynthesis.

Angew Chem Int Ed Engl 2003 Jun;42(25):2864-7

Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, Haus F, 81377 München, Germany.

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http://dx.doi.org/10.1002/anie.200351066DOI Listing
June 2003

Four lignans from Commiphora erlangeriana.

J Nat Prod 2002 Sep;65(9):1252-7

Department of Chemistry, Addis Ababa University, P.O. Box 30270, Ethiopia.

Four new lignans, two of the polygamatin-type, named erlangerin A (1) and erlangerin B (2), and two related to podophyllotoxin, named erlangerin C (3) and erlangerin D (4), were isolated from the resin of Commiphora erlangeriana, a plant occurring in Ethiopia and Somalia. The structures of these compounds including their relative stereochemistry were elucidated on the basis of spectral evidence, chemical data, and X-ray crystallographic analysis.
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http://dx.doi.org/10.1021/np020028jDOI Listing
September 2002

Draculone, a new anthraquinone pigment from the tropical lichen Melanotheca cruenta.

Z Naturforsch C J Biosci 2002 Jul-Aug;57(7-8):565-7

Department Chemie der Ludwig-Maximilians-Universität, München, Germany.

A new red anthraquinone, draculone, has been isolated from the corticolous tropical lichen Melanotheca cruenta (= Trypethelium cruentum = Pyrenula cruenta) together with minor quantities of the known anthraquinone pigment haematommone. The structure of draculone was determined as 2-acetyl-1,3,4,6,8-pentahydroxyanthraquinone by spectroscopic methods.
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http://dx.doi.org/10.1515/znc-2002-7-801DOI Listing
October 2002

Total syntheses of the marine pyrrole alkaloids polycitone A and B.

Org Lett 2002 Sep;4(19):3287-8

Chemie Department, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13 (Haus F), Germany.

Polycitone B (2) was obtained in four steps from pyrrole dicarboxylic acid 3, including Friedel-Crafts reaction of the corresponding acid chloride with anisole. The conversion of 2 into polycitone A (1) was achieved in two steps via Mitsunobu alkylation of the pyrrolic NH group. The synthesis of polycitone A proceeds in 18% overall yield and offers the possibility of varying the substituents on the pyrrole ring.
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http://dx.doi.org/10.1021/ol026555bDOI Listing
September 2002

Studies on the biosynthesis of striatal-type diterpenoids and the biological activity of herical.

Z Naturforsch C J Biosci 2002 Mar-Apr;57(3-4):263-71

LB Biotechnologie der Universität, Kaiserslautern, Germany.

Feeding experiments with specifically 13C-labeled glucose disclosed that the diterpenoid part of the striatals/striatins is formed via the mevalonate pathway, whereas the pentose moiety originates either via glucuronic acid (70%) or the pentose phosphate cycle (30%). Application of radioactively labeled herical to cultures of Hericium ramosum demonstrates the pivotal role of this cyathane-xyloside in striatal biosynthesis. Herical inhibits a large spectrum of fungi and bacteria and shows cytotoxic and hemolytic properties.
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http://dx.doi.org/10.1515/znc-2002-3-411DOI Listing
July 2002

Pityriacitrin -- an ultraviolet-absorbing indole alkaloid from the yeast Malassezia furfur.

Arch Dermatol Res 2002 May 5;294(3):131-4. Epub 2002 Apr 5.

Department of Dermatology, Justus Liebig University Giessen, Gaffkystrasse 14, 35385 Giessen, Germany.

As the main nitrogen source in Malassezia furfur, tryptophan induces the formation of fluorochromes and pigments, which make the yeast less sensitive to UV light. To detect a chemical UV filter, M. furfur (CBS 1878) was incubated at 30 degrees C for 14 days on a pigment-inducing medium and agar extracts were purified by column chromatography, preparative TLC and HPLC. Structural analysis of the pure metabolites was performed by mass spectroscopy and NMR. A yellow compound eluting from the column with 64% acetonitrile was found to be a potential UV filter because of its broad UV absorption (lambda(max) 389, 315, 289, 212 nm). It was an indole derivative (C(20)H(13)N(3)O; pityriacitrin) which had recently been shown to be a potent UV filter in bacteria. Its UV protective properties were confirmed in a yeast model and also in humans. Pityriasis versicolor induced by Malassezia yeasts is characterized by depigmented skin areas showing reduced melanin synthesis but no increased UV sensitivity. This UV protection might be explained by the presence of pityriacitrin which is produced by M. furfur.
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http://dx.doi.org/10.1007/s00403-002-0294-2DOI Listing
May 2002

Blennione, a green aminobenzoquinone derivative from Lactarius blennius.

J Nat Prod 2002 May;65(5):725-7

Department Chemie der Ludwig-Maximilians-Universität, Butenandtstrasse 5-13, D-81377 München, Germany.

A green pigment, blennione (1), was isolated from fruit bodies of the toadstool Lactarius blennius. Its structure was established by 2D NMR methods and confirmed by a biomimetic synthesis. Compound 1 represents a diphenylquinone derivative, which may be formed biosynthetically from two 3,6-dihydroxyanthranilic acid units.
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http://dx.doi.org/10.1021/np0106541DOI Listing
May 2002

Polyene pigments from fruit-bodies of boletus laetissimus and B. rufo-aureus (basidiomycetes).

Phytochemistry 1998 Nov;49(6):1693-1697

Institut für Organische Chemie der Universität, Karlstrasse 23, 80333, Munich, Germany

From fruit-bodies of the Japanese mushroom Boletus laetissimus two polyene pigments boletocrocin A and B were isolated and their structures determined by spectroscopic methods. The compounds represent diamides of hexadecaheptaenedioic acid with isoleucine and either aspartic acid or asparagine. The L-configuration of the amino acids was established after acid hydrolysis. The structures of five structurally related minor pigments were elucidated by LC-ESIMS.
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http://dx.doi.org/10.1016/s0031-9422(98)00319-7DOI Listing
November 1998

Stereoselective Modification of a Cyclopentapeptide via an alpha-(Ethylthio)glycine Residue.

J Org Chem 1997 Nov;62(24):8474-8478

Institut für Organische Chemie der Universität München Karlstrasse 23, D-80333 München, Germany.

The solid-phase synthesis of cyclo[Val-D-Gly(SEt)-Pro-Phe-D-Ala] (5) on Kaiser's oxime resin is described. Conversion of 5 to the reactive alpha-chloroglycine derivative 9 allowed the stereoselective addition of thiols, alcohols, amines and other nucleophiles with formation of the modified cyclopeptides 11a-n.
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http://dx.doi.org/10.1021/jo971295aDOI Listing
November 1997

Strobilurins: Evolution of a New Class of Active Substances.

Angew Chem Int Ed Engl 1999 May;38(10):1328-1349

Fachbereich Biologie, Lehrbereich Biotechnologie, Paul-Ehrlich-Strasse, Gebäude 23, D-67663 Kaiserslautern (Germany).

A fungus that grows on pinecones yields a compound with antifungal activity that has become the natural model for a significant innovation in crop protection. Variation and optimization of the lead structure of strobilurin A (1) and selection of derivatives which fulfill all practical requirements, for example, kresoxim-methyl (2), led to an exciting and pan-industrial competition for the development of the strobilurines as a new, highly active, and broadly applicable class of fungicides-a fascinating success story.
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http://dx.doi.org/10.1002/(SICI)1521-3773(19990517)38:10<1328::AID-ANIE1328>3.0.CO;2-1DOI Listing
May 1999

An Iron(III)-Catechol Complex as a Mushroom Pigment.

Angew Chem Int Ed Engl 1998 Dec;37(23):3292-3295

Physik-Department E15 der Technischen Universität München, Garching (Germany).

An iron ink has been detected as the pigment of the beautiful dark violet mushroom Cortinarius violaceus. The amino acid (R)-β-dopa (1) is the ligand of the 1:2 Fe -catechol complex.
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http://dx.doi.org/10.1002/(SICI)1521-3773(19981217)37:23<3292::AID-ANIE3292>3.0.CO;2-NDOI Listing
December 1998