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Publikationen - Natur- und Wirkstoffchemie

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Publikation

Lam, Y. T. H.; Palfner, G.; Lima, C.; Porzel, A.; Brandt, W.; Frolov, A.; Sultani, H.; Franke, K.; Wagner, C.; Merzweiler, K.; Wessjohann, L. A.; Arnold, N.; Nor-guanacastepene pigments from the Chilean mushroom Cortinarius pyromyxa Phytochemistry 165, 112048, (2019) DOI: 10.1016/j.phytochem.2019.05.021

For the first time, the pigment composition of basidiocarps from the Chilean mushroom Cortinarius pyromyxa was studied under various aspects like phylogeny, chemistry and antibiotic activity. A molecular biological study supports the monotypic position of C. pyromyxa in subgenus Myxacium, genus Cortinarius. Four undescribed diterpenoids, named pyromyxones A-D, were isolated from fruiting bodies of C. pyromyxa. Their chemical structures were elucidated based on comprehensive one- and two-dimensional NMR spectroscopic analysis, ESI-HRMS measurements, as well as X-ray crystallography. In addition, the absolute configurations of pyromyxones A-D were established with the aid of JH,H, NOESY spectra and quantum chemical CD calculation. The pyromyxones A-D possess the undescribed nor-guanacastane skeleton. Tested pyromyxones A, B, and D exhibit only weak activity against gram-positive Bacillus subtilis and gram-negative Aliivibrio fischeri as well as the phytopathogenic fungi Botrytis cinerea, Septoria tritici and Phytophthora infestans.
Publikation

Walther, T.; Herzog, R.; Kaluđerović, M. R.; Wagner, C.; Schmidt, H.; Kaluđerović, G. N.; Traceable platinum(II) complexes with alkylene diamine-derived ligands: synthesis, characterization and in vitro studies J. Coord. Chem. 71, 243-257, (2018) DOI: 10.1080/00958972.2018.1431392

Diiodido- (6a/6b) and dichloridoplatinum(II) complexes (7a/7b) with fluorescent ligands 2-[(2-aminoethyl)amino]ethyl-2-(methylamino)benzoate (5a) and 2-amino-1-(aminoethyl)ethyl-2-(methylamino)benzoate (5b) were prepared and characterized by elemental analysis, ESI-MS analysis, fluorescence spectrometry, as well as 1H, 13C, and 195Pt NMR spectroscopy. All compounds have been tested against A2780 ovarian cancer, A549 lung carcinoma, and HT-29 colon cancer cell lines using sulforhodamine-B assay. The activity increased from ligand precursors, diiodido- to dichloridoplatinum(II) complexes, except against HT-29 cell line where diiodido and dichlorido expressed similar activity. These compounds enter the tumor cells and emit a bright fluorescence at ca. 470 nm, mainly targeting nuclei.
Publikation

Quang, D. N.; Wagner, C.; Merzweiler, K.; Abate, D.; Porzel, A.; Schmidt, J.; Arnold, N.; Pyrofomins A-D, polyoxygenated sesquiterpenoids from Pyrofomes demidoffii Fitoterapia 112, 229-232, (2016) DOI: 10.1016/j.fitote.2016.06.004

Pyrofomins A-D, four polyoxygenated sesquiterpenoids have been isolated from the methanolic extract of the fruit bodies of Pyrofomes demidoffii. Their structures are elucidated by IR, HR-FTICR-MS, and 2D NMR spectroscopy. Furthermore, the cedrane carbon skeleton of pyrofomin A (1) is confirmed by X-ray crystallographic analysis. The sesquiterpenoids 1–4 show neither cytotoxicity against KB cells nor antimicrobial activity.
Publikation

Kluge, T.; Bette, M.; Rüffer, T.; Bruhn, C.; Wagner, C.; Ströhl, D.; Schmidt, J.; Steinborn, D.; Activation of Acetyl Ligands through Hydrogen Bonds: A New Way to Platinum(II) Complexes Bearing Protonated Iminoacetyl Ligands Organometallics 32, 7090-7106, (2013) DOI: 10.1021/om400812w

The dinuclear platina-β-diketone [Pt2{(COMe)2H}2(μ-Cl)2] (1) reacted with 2-pyridyl-functionalized monoximes and with dioximes in the presence of NaOMe to yield oxime–diacetyl platinum(II) complexes [Pt(COMe)2(2-pyCR═NOH)] (R = H, 4a; Me, 4b; Ph, 4c) and [Pt(COMe)2(HON═CR–CR═NOH)] (R/R = Me/Me, 5a; Ph/Ph, 5b; (CH2)4, 5c; NH2/NH2, 5d), respectively. The strong intramolecular O–H···O hydrogen bonds in these complexes give rise to an activation of the acetyl ligands for Schiff-base type reactions, thus forming with primary amines iminoacetyl platinum complexes [Pt(COMe)(CMe═NHR′)(2-pyCR═NO)] (R/R′ = H/Bn, 6a; Me/Bn, 6b; Ph/Bn, 6c; H/CH2CH2Ph, 6d; H/CH2CH═CH2, 6e; Bn = benzyl) and [{Pt(CMe═NHR′)2(ON═CR–CR═NO)}2] (R/R = Me/Me, 7a–d; Ph/Ph, 8a–d; (CH2)4, 9a; R′ = Bn, a; CH2CH2Ph, b; CH2CH═CH2, c; CH2CH2OH, d). The intramolecular N–H···O hydrogen bonds in type 6–9 complexes make clear that protonated iminoacetyl ligands (i.e., aminocarbene ligands) and deprotoanted oxime ligands are present. These complexes could also be obtained in reactions of [Pt(COMe)2(NH2R′)2] (3) with pyridyl-functionalized monoximes and with dioximes where type 4/5 complexes were found to be intermediates. In solution, the bis(iminoacetyl) complexes 7–9 were found to be present as dimers (as also 8a in the solid state) with smaller amounts of monomers. The importance of hydrogen bonds for activation of acetyl ligands was further evidenced by synthesis of complexes [Pt(COMe)2(2-pyCH═NOMe)] (10) and [Pt(COMe)2(HON═CMe–CMe═NOMe)] (11) bearing O-methylated oxime ligands and their reactivty toward amines. The hydrogen-bond activated acetyl and iminoacetyl ligands in type 5, 7, and 8 complexes were found to undergo in CD3OD solutions facile H/D exchange reactions resulting in complexes bearing C(CD3)═O/C(CD3)═NDR′ ligands. The constitution of all complexes was unambiguously confirmed analytically, spectroscopically and in part by single-crystal X-ray diffraction analyses. Structural and NMR parameters as well as DFT calculations gave evidence for relatively strong intramolecular hydrogen bonds.
Publikation

Block, M.; Bette, M.; Wagner, C.; Schmidt, J.; Steinborn, D.; Rhodium(I) complexes with κP coordinated ω-phosphinofunctionalized alkyl phenyl sulfide, sulfoxide and sulfone ligands and their reactions with sodium bis(trimethylsilyl)amide and Ag[BF4] J. Organomet. Chem. 696, 1768-1781, (2011) DOI: 10.1016/j.jorganchem.2010.12.019

Reactions of ω-diphenylphosphinofunctionalized alkyl phenyl sulfides Ph2P(CH2)nSPh (n = 1, 1a; 2, 2a; 3, 3a), sulfoxides Ph2P(CH2)nS(O)Ph (n = 1, 1b; 2, 2b; 3, 3b) and sulfones Ph2P(CH2)nS(O)2Ph (n = 1, 1c; 2, 2c; 3, 3c) with dinuclear chlorido bridged rhodium(I) complexes [(RhL2)2(μ-Cl)2] (L2 = cycloocta-1.5-diene, cod, 4; bis(diphenylphosphino)ethane, dppe, 5) afforded mononuclear Rh(I) complexes of the type [RhCl{Ph2P(CH2)nS(O)xPh-κP}(cod)]1 (n/x = 1/0, 6a; 1/1, 6b; 1/2, 6c; 2/0, 8a; 2/1, 8b; 2/2, 8c; 3/0, 10a; 3/1, 10b; 3/2, 10c) and [RhCl{Ph2P(CH2)nS(O)xPh-κP}(dppe)] (n/x = 1/0, 7a; 1/1, 7b; 1/2, 7c; 2/0, 9a; 2/1, 9b; 2/2, 9c; 3/0, 11a; 3/1, 11b; 3/2, 11c) having the P^S(O)x ligands κP coordinated. Addition of Ag[BF4] to complexes 6–11 in CH2Cl2 led with precipitation of AgCl to cationic rhodium complexes of the type [Rh{Ph2P(CH2)nS(O)xPh-κP,κS/O}L2][BF4] having bound the P^S(O)x ligands bidentately in a κP,κS (13a–18a, 15b–18b) or a κP,κO (13b, 14b, 13c–18c) coordination mode. Unexpectedly, the addition of Ag[BF4] to 6a in THF afforded the trinuclear cationic rhodium(I) complex [Rh3(μ-Cl)(μ-Ph2PCH2SPh-κP:κS)4][BF4]2·4THF (12·4THF) with a four-membered Rh3Cl ring as basic framework. Addition of sodium bis(trimethylsilyl)amide to complexes 6–11 led to a selective deprotonation of the carbon atom neighbored to the S(O)x group (α-C) yielding three different types of organorhodium complexes: a) Organorhodium intramolecular coordination compounds of the type [Rh{CH{S(O)xPh}CH2CH2PPh2-κC,κP}L2] (22a–c, 23a–c), b) zwitterionic complexes [Rh{Ph2PCHS(O)xPh-κP,κS/O}L2] having κP,κS (21a, 21b) and κP,κO (20b/c, 21c) coordinated anionic [Ph2PCHS(O)xPh] ligands, and c) the dinuclear rhodium(I) complex [{Rh{μ-CH(SPh)PPh2-κC:κP}(cod)}2] (19). All complexes were fully characterized spectroscopically and complexes 15b, 15c, 12·4THF and 19·THF additionally by X-ray diffraction analysis. DFT calculations of zwitterionic complexes gave insight into the coordination mode of the [Ph2PCHS(O)Ph] ligand (κP,κS versus κP,κO).
Publikation

Kelly, M. E.; Dietrich, A.; Gómez-Ruiz, S.; Kalinowski, B.; Kaluderović, G. N.; Müller, T.; Paschke, R.; Schmidt, J.; Steinborn, D.; Wagner, C.; Schmidt, H.; Platinum(IV) Metallacrown Ethers: Synthesis, Structures, Host Properties and Anticancer Evaluation Organometallics 27, 4917-4927, (2008) DOI: 10.1021/om800323z

Platinum(IV) metallacrown ethers [PtBr2Me2{im(CH2CH2O)xCH2CH2im}] (im = imidazol-1-yl; x = 2−5, 7; 3−7) and [PtBr2Me2{bim(CH2CH2O)xCH2CH2bim}] (bim = benzimidazol-1-yl; x = 1, 2, 5, 7; 9−12) were synthesized via the reaction of [(PtBr2Me2)n] with the appropriate α,ω-bis(imidazol-1-yl) or α,ω-bis(benzimidazol-1-yl) polyether. Reactions with 1,2-bis(imidazol-1-yl)ethane, bis(2-(imidazol-1-yl)ethyl) ether, or 1,2-bis(benzimidazol-1-yl)ethane yielded the dinuclear complexes [(PtBr2Me2)2{μ-im(CH2CH2O)xCH2CH2im}2] (x = 0, 1; 1, 2) and [(PtBr2Me2)2{μ-bimCH2CH2bim}2] (8), respectively. In addition, the diiodo complex [PtI2Me2{im(CH2CH2O)2CH2CH2im}] (13) was prepared from the reaction of [PtMe2(cod)] with I2 in the presence of im(CH2CH2O)2CH2CH2im. Characterization by microanalysis and NMR spectroscopy, as well as X-ray crystal structure analysis of several of the metallacrown ethers (3, 5, 9 and 10) and dinuclear complexes (2 and 8), is described. The ability of the larger metallacrown ethers (5−7, 11 and 12) to act as hosts to either dibenzyl- or di-n-butylammonium ions is investigated in solution (NMR and ESI-MS). Finally, several of these metallacrown ethers were found to possess in vitro antitumor activity on three tumor cell lines (liposarcoma, A549 and 518A2). The activity of these complexes, all of which were found to induce apoptotic cell death, is discussed relative to their structure and the findings of platinum uptake studies.
Publikation

Kelly, M. E.; Gómez-Ruiz, S.; Schmidt, J.; Wagner, C.; Schmidt, H.; Platinum(IV) complexes with α,ω-bis(pyrazol-1-yl) alkanediyl and diethyl ether/thioether ligands. Crystal structures of dibromodimethyl[1,2-bis(pyrazol-1-yl)ethane]platinum(IV) and trimethyl-bis[2-(pyrazol-1-yl)ethyl]etherplatinum(IV) tetrafluoroborate Polyhedron 27, 3091-3096, (2008) DOI: 10.1016/j.poly.2008.07.003

Reactions of the flexible α,ω-bis(pyrazol-1-yl) compounds 1,2-bis(pyrazol-1-yl)ethane (L1), 1,8-bis(pyrazol-1-yl)-n-octane (L2), bis[2-(pyrazol-1-yl)ethyl]ether (L3) and bis[2-(pyrazol-1-yl)ethyl]thioether (L4) with precursor organometallic platinum complexes ([(PtBr2Me2)n], [(PtIMe3)4] and [(PtMe2(cod)]/I2) are described herein. The spectroscopic characterization of the platinum(IV) products of these reactions [PtBr2Me2{pz(CH2)mpz}], m = 2 (1) or 8 (2), [PtI2Me2{pz(CH2)2pz}] (3), [PtMe3(pzCH2CH2OCH2CH2pz)][BF4] (4) and [PtMe3(pzCH2CH2SCH2CH2pz)][CF3SO3] (5), where ‘pz’ is pyrazol-1-yl, is discussed. Furthermore, solid state structures of 1, a complex with a seven-membered chelate ring, and 4, a complex bearing the neutral κ2N,N′,κO ligand bis[2-(pyrazol-1-yl)ethyl]ether (L3) are reported.
Publikation

Westermann, B.; Michalik, D.; Schaks, A.; Kreye, O.; Wagner, C.; Merzweiler, K.; Wessjohann, L. A.; Natural Product Inspired meta/para’-Biaryl Ether Lactam Macrocycles by Double Ugi Multicomponent Reactions Heterocycles 73, 863-872, (2007) DOI: 10.3987/COM-07-S(U)21

Isonitrile meta/para’-functionalized biaryl ethers can serve as key building blocks for the highly efficient and diverse one step production of natural product inspired peptide/peptoid macrocycles, thereby forming up to 54-membered rings with eight or even sixteen new bonds. Aliphatic diamine and diacid tethers give access to two different classes of biaryl ether cyclopeptoids, either with exo/endo or exclusively endo dipeptidic moieties.
Publikation

Vetter, C.; Wagner, C.; Schmidt, J.; Steinborn, D.; Synthesis and characterization of platinum(IV) complexes with N,S and S,S heterocyclic ligands Inorg. Chim. Acta 359, 4326-4334, (2006) DOI: 10.1016/j.ica.2006.06.007

The reactions of [PtMe3(OAc)(bpy)] (4) with the N,S and S,S containing heterocycles, pyrimidine-2-thione (pymtH), pyridine-2-thione (pytH), thiazoline-2-thione (tztH) and thiophene-2-thiol (tptH), resulted in the formation of the monomeric complexes [PtMe3(-κS)(bpy)] ( = pymt, 5; pyt, 6; tzt, 7; tpt, 8), where the heterocyclic ligand is coordinated via the exocyclic sulfur atom. In contrast, in the reactions of [PtMe3(OAc)(Me2CO)x] (3, x = 1 or 2) with pymtH, pytH, tztH and tptH dimeric complexes [{PtMe3(μ-)}2] (μ- = pymt, 9; pyt, 10; tzt, 11) and the tetrameric complex [{PtMe3(μ3-tpt-κS)}4] (12), respectively, were formed. The complexes were characterized by microanalyses, 1H and 13C NMR spectroscopy and negative ESI-MS (12) measurements. Single-crystal X-ray diffraction analysis of [PtMe3(pymt-κS)(bpy)] (5) exhibited a conformation where the pymt ligand lies nearly perpendicular to the complex plane above the bpy ligand that was also confirmed by quantum chemical calculations on the DFT level of theory.
Publikation

Voigt, B.; Porzel, A.; Adam, G.; Golsch, D.; Adam, W.; Wagner, C.; Merzweiler, K.; Synthesis of 2,24-Diepicastasterone and 3,24-Diepicastasterone as Potential Brassinosteroid Metabolites of the Cockroach Periplaneta americana Collect. Czech. Chem. Commun. 67, 91-102, (2002) DOI: 10.1135/cccc20020091

Investigations of the metabolic conversion of the phytohormone 24-epicastasterone (1) in the cockroach Periplaneta americana (L.) required the synthesis of 2,24-diepicastasterone (4), 3,24-diepicastasterone (7b) and 2-dehydro-3,24-diepicastasterone (9) as reference standards. 2,24-Diepicastasterone (4) was synthesized from 2α,3α-epoxy derivative 2 as well as from the 2β,3β-epoxy-22,23-diol 3 by acid-catalyzed water addition to the epoxy function leading to the desired 2β,3α-trans functionality. 3,24-Diepicastasterone (7b) was prepared by NaBH4-reduction of the 3-oxo derivative 6. Upon deprotection conditions from the ketol acetonides 6 and 8 in both cases 2-dehydro-3,24-diepicastasterone (9) was obtained. The structure of 2,24-diepicastasterone (4) was confirmed by X-ray analysis.
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