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Garcia KYM, Phukhamsakda C, Quimque MTJ, Hyde KD, Stadler M, Macabeo APG. Catechol-Bearing Polyketide Derivatives from Sparticola junci. JOURNAL OF NATURAL PRODUCTS 2021; 84:2053-2058. [PMID: 34197704 DOI: 10.1021/acs.jnatprod.1c00415] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Sparticols A (1) and B (2), two catechol-bearing naphthalenedioxy derivatives, were isolated from the submerged culture of the Spanish broom inhabiting Dothideomycetes fungus, Sparticola junci. The structures of 1 and 2 were established by NMR spectroscopic analysis and high-resolution mass spectrometry. The 8S absolute configuration of their β-hydroxy functionalities was determined by ECD-TDDFT. Both compounds exhibited inhibitory activity against Staphylococcus aureus with an MIC value of 66.6 μg/mL. Polyketides 1 and/or 2 may be associated with pathways cascading to seco-spirodioxynapthalene derivatives.
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Affiliation(s)
- Katherine Yasmin M Garcia
- The Graduate School, University of Santo Tomas, España Boulevard, 1015 Manila, Philippines
- Laboratory for Organic Reactivity, Discovery and Synthesis (LORDS), Research Center for the Natural and Applied Sciences, University of Santo Tomas, España Boulevard, 1015 Manila, Philippines
| | - Chayanard Phukhamsakda
- Institute of Plant Protection, College of Agriculture, Engineering Research Center of Chinese Ministry of Education for Edible and Medicinal Fungi, Jilin Agricultural University, Changchun City, Jilin Province, People's Republic of China, 130118
- Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai 57100, Thailand
| | - Mark Tristan J Quimque
- The Graduate School, University of Santo Tomas, España Boulevard, 1015 Manila, Philippines
- Laboratory for Organic Reactivity, Discovery and Synthesis (LORDS), Research Center for the Natural and Applied Sciences, University of Santo Tomas, España Boulevard, 1015 Manila, Philippines
| | - Kevin D Hyde
- Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai 57100, Thailand
| | - Marc Stadler
- Department of Microbial Drugs, Helmholtz Centre for Infection Research and German Centre for Infection Research (DZIF), partner site Hannover/Braunschweig, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Allan Patrick G Macabeo
- Laboratory for Organic Reactivity, Discovery and Synthesis (LORDS), Research Center for the Natural and Applied Sciences, University of Santo Tomas, España Boulevard, 1015 Manila, Philippines
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2
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Broberg A, Nord C, Levenfors JJ, Bjerketorp J, Guss B, Öberg B. In-peptide amino acid racemization via inter-residue oxazoline intermediates during acidic hydrolysis. Amino Acids 2021; 53:323-331. [PMID: 33586040 PMCID: PMC7979671 DOI: 10.1007/s00726-021-02951-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 02/02/2021] [Indexed: 11/26/2022]
Abstract
Isopedopeptins are antibiotic cyclic lipodepsipeptides containing the subsequence L-Thr—L-2,3-diaminopropanoic acid—D-Phe—L-Val/L-3-hydroxyvaline. Acidic hydrolysis of isopedopeptins in D2O showed the D-Phe residues to racemize extensively in peptides with L-3-hydroxyvaline but not in peptides with L-Val. Similarly, one Leu residue in pedopeptins, which are related peptides containing the subsequence Leu—2,3-diaminopropanoic acid—Leu—L-Val/L-3-hydroxyvaline, was found to racemize in peptides with L-3-hydroxyvaline. Model tetrapeptides, L-Ala—L-Phe—L-Val/3-hydroxyvaline—L-Ala, gave the corresponding results, i.e. racemization of L-Phe only when linked to a L-3-hydroxyvaline. We propose the racemization to proceed via an oxazoline intermediate involving Phe/Leu and the L-3-hydroxyvaline residues. The 3-hydroxyvaline residue may form a stable tertiary carbocation by loss of the sidechain hydroxyl group as water after protonation. Elimination of the Phe/Leu H-2 and ring-closure from the carbonyl oxygen onto the carbocation results in the suggested oxazoline intermediate. The reversed reaction leads to either retained or inversed configuration of Phe/Leu. Such racemization during acidic hydrolysis may occur whenever a 3-hydroxyvaline residue or any amino acid that can form a stable carbocation on the C-3, is present in a peptide. The proposed mechanism for racemization was supported by incorporation of 18O in the 3-hydroxyvaline sidechain when the acidic hydrolysis was performed in H2O/H218O (1:1). The 2,3-diaminopropanoic residues of isopedopeptins and pedopeptins were also found to racemize during acidic hydrolysis, as previously described. Based on the results, the configuration of the Leu and 2,3-diaminopropanoic acid residues of the pedopeptins were reassigned to be L-Leu and D-Leu, and 2 × L-2,3-diaminopropanoic acid.
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Affiliation(s)
- Anders Broberg
- Department of Molecular Sciences, Uppsala BioCentrum, Swedish University of Agricultural Sciences, P.O. Box 7015, 750 07 Uppsala, Sweden
| | - Christina Nord
- Department of Molecular Sciences, Uppsala BioCentrum, Swedish University of Agricultural Sciences, P.O. Box 7015, 750 07 Uppsala, Sweden
| | - Jolanta J. Levenfors
- Department of Molecular Sciences, Uppsala BioCentrum, Swedish University of Agricultural Sciences, P.O. Box 7015, 750 07 Uppsala, Sweden
- Ultupharma AB, Södra Rudbecksgatan 13, 752 36 Uppsala, Sweden
| | - Joakim Bjerketorp
- Department of Molecular Sciences, Uppsala BioCentrum, Swedish University of Agricultural Sciences, P.O. Box 7015, 750 07 Uppsala, Sweden
- Ultupharma AB, Södra Rudbecksgatan 13, 752 36 Uppsala, Sweden
| | - Bengt Guss
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, P.O. Box 7036, 750 07 Uppsala, Sweden
| | - Bo Öberg
- Ultupharma AB, Södra Rudbecksgatan 13, 752 36 Uppsala, Sweden
- Department of Medicinal Chemistry, Uppsala University, P.O. Box 574, 751 23 Uppsala, Sweden
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Liu X, Li S, Wei X, Zhao Y, Lai D, Zhou L, Wang M. Total synthesis of Palmarumycin BGs, C 1 and Guignardin E. RSC Adv 2020; 10:1588-1594. [PMID: 35494718 PMCID: PMC9047396 DOI: 10.1039/c9ra10316c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 12/19/2019] [Indexed: 11/21/2022] Open
Abstract
The first total synthesis of Palmarumycin BG1–3, BG5–6, C1 and Guignardin E (1–7) were achieved by the same intermediate Palmarumycin C2 through a N-benzyl cinchoninium chloride-catalyzed epoxidation, an organoselenium-mediated reduction, and a cerium(iii) chloride hydrate-promoted regioselective ring-opening and elimination of cyclic α,β-epoxy ketone as the key steps via6–7 step routes using 1,8-dihydroxynaphthalene (DHN) and 5-methoxytetralone as the starting materials in overall yields of 1.0–17.4%, respectively. Their structures and absolute configurations were characterized and determined by 1H, 13C NMR, IR, HR-ESI-MS and X-ray diffraction data. These compounds displayed significant inhibition activities against HCT116, U87-MG, HepG2, BGC823 and PC9 cell lines. The first total syntheses of Palmarumycin BG1–3, BG5–6, C1 and Guignardin E were achieved. These compounds displayed significant inhibition activities against HCT116, U87-MG, HepG2, BGC823 and PC9 cell lines.![]()
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Affiliation(s)
- Xinlei Liu
- Department of Applied Chemistry, College of Sciences, China Agricultural University Beijing 100193 People's Republic of China
| | - Shuyi Li
- Department of Applied Chemistry, College of Sciences, China Agricultural University Beijing 100193 People's Republic of China
| | - Xinyu Wei
- Department of Applied Chemistry, College of Sciences, China Agricultural University Beijing 100193 People's Republic of China
| | - Yu Zhao
- Department of Applied Chemistry, College of Sciences, China Agricultural University Beijing 100193 People's Republic of China
| | - Daowan Lai
- Department of Plant Pathology, College of Plant Protection, China Agricultural University Beijing 100193 People's Republic of China
| | - Ligang Zhou
- Department of Plant Pathology, College of Plant Protection, China Agricultural University Beijing 100193 People's Republic of China
| | - Mingan Wang
- Department of Applied Chemistry, College of Sciences, China Agricultural University Beijing 100193 People's Republic of China
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Xu YM, Mafezoli J, Oliveira MCF, U'Ren JM, Arnold AE, Gunatilaka AAL. Anteaglonialides A-F and Palmarumycins CE(1)-CE(3) from Anteaglonium sp. FL0768, a Fungal Endophyte of the Spikemoss Selaginella arenicola. JOURNAL OF NATURAL PRODUCTS 2015; 78:2738-2747. [PMID: 26539727 DOI: 10.1021/acs.jnatprod.5b00717] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Anteaglonialides A-F (1-6), bearing a spiro[6-(tetrahydro-7-furanyl)cyclohexane-1,2'-naphtho[1,8-de][1,3]-dioxin]-10-one skeleton, three new spirobisnaphthalenes, palmarumycins CE1-CE3 (7-9), nine known palmarumycin analogues, palmarumycins CP5 (10), CP4a (11), CP3 (12), CP17 (13), CP2 (14), and CP1 (15), CJ-12,371 (16), 4-O-methyl CJ-12,371 (17), and CP4 (18), together with a possible artifact, 4a(5)-anhydropalmarumycin CE2 (8a), and four known metabolites, O-methylherbarin (19), herbarin (20), herbaridine B (21), and hyalopyrone (22), were encountered in a cytotoxic extract of a potato dextrose agar culture of Anteaglonium sp. FL0768, an endophytic fungus of the sand spikemoss, Selaginella arenicola. The planar structures and relative configurations of the new metabolites 1-9 were elucidated by analysis of extensive spectroscopic data, and the absolute configuration of 1 was determined by the modified Mosher's ester method. Application of the modified Mosher's ester method combined with the NOESY data resulted in revision of the absolute configuration previously proposed for 10. Co-occurrence of 1-6 and 7-18 in this fungus led to the proposal that the anteagloniolides may be biogenetically derived from palmarumycins. Among the metabolites encountered, anteaglonialide F (6) and known palmarumycins CP3 (12) and CP1 (15) exhibited strong cytotoxic activity against the human Ewing's sarcoma cell line CHP-100, with IC50 values of 1.4, 0.5, and 1.6 μM, respectively.
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Affiliation(s)
- Ya-ming Xu
- Southwest Center for Natural Products Research and Commercialization, School of Natural Resources and the Environment, College of Agriculture and Life Sciences, University of Arizona , 250 E. Valencia Road, Tucson, Arizona 85706, United States
| | - Jair Mafezoli
- Southwest Center for Natural Products Research and Commercialization, School of Natural Resources and the Environment, College of Agriculture and Life Sciences, University of Arizona , 250 E. Valencia Road, Tucson, Arizona 85706, United States
- Departamento de Química Orgânica e Inorgânica, Universidade Federal do Ceará , Campus do Pici, Caixa Postal 6044, Fortaleza-CE 60455-970, Brazil
| | - Maria C F Oliveira
- Southwest Center for Natural Products Research and Commercialization, School of Natural Resources and the Environment, College of Agriculture and Life Sciences, University of Arizona , 250 E. Valencia Road, Tucson, Arizona 85706, United States
- Departamento de Química Orgânica e Inorgânica, Universidade Federal do Ceará , Campus do Pici, Caixa Postal 6044, Fortaleza-CE 60455-970, Brazil
| | | | | | - A A Leslie Gunatilaka
- Southwest Center for Natural Products Research and Commercialization, School of Natural Resources and the Environment, College of Agriculture and Life Sciences, University of Arizona , 250 E. Valencia Road, Tucson, Arizona 85706, United States
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6
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Antimicrobial and antioxidant activities and effect of 1-hexadecene addition on palmarumycin C2 and C3 yields in liquid culture of endophytic fungus Berkleasmium sp. Dzf12. Molecules 2013; 18:15587-99. [PMID: 24352015 PMCID: PMC6270283 DOI: 10.3390/molecules181215587] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 12/03/2013] [Accepted: 12/09/2013] [Indexed: 11/21/2022] Open
Abstract
Two spirobisnaphthalenes, namely palmarumycins C2 and C3, were isolated from cultures of the endophytic fungus Berkleasmium sp. Dzf12 after treatment with 1-hexadecene. After addition of 1-hexadecene at 10% to the medium on day 6 of culture, the maximal yields of palmarumycins C2 and C3 were obtained as 0.40 g/L and 1.19 g/L, which were 40.00 fold and 59.50 fold higher, respectively, in comparison with those of the control (0.01 g/L and 0.02 g/L). The results indicated that addition of 1-hexadecene can be an effective strategy for enhancing the production of palmarumycins C2 and C3 in liquid culture of endophytic fungus Berkleasmium sp. Dzf12. Palmarumycin C3 exhibited stronger antimicrobial and antioxidant activities than palmarumycin C2.
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Huynh THV, Shim I, Bohr H, Abrahamsen B, Nielsen B, Jensen AA, Bunch L. Structure-activity relationship study of selective excitatory amino acid transporter subtype 1 (EAAT1) inhibitor 2-amino-4-(4-methoxyphenyl)-7-(naphthalen-1-yl)-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile (UCPH-101) and absolute configurational assignment using infrared and vibrational circular dichroism spectroscopy in combination with ab initio Hartree-Fock calculations. J Med Chem 2012; 55:5403-12. [PMID: 22594609 DOI: 10.1021/jm300345z] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The excitatory amino acid transporters (EAATs) play essential roles in regulating the synaptic concentration of the neurotransmitter glutamate in the mammalian central nervous system. To date, five subtypes have been identified, named EAAT1-5 in humans, and GLAST, GLT-1, EAAC1, EAAT4, and EAAT5 in rodents, respectively. In this paper, we present the design, synthesis, and pharmacological evaluation of seven 7-N-substituted analogues of UCPH-101/102. Analogue 9 inhibited EAAT1 in the micromolar range (IC(50) value 20 μM), whereas analogues 8 and 10 were inactive (IC(50) values >100 μM). The diastereomeric pairs 11a/11b and 12a/12b were separated by HPLC and the absolute configuration assigned by VCD technique in combination with ab initio Hartree-Fock calculations. Analogues 11a (RS-isomer) and 12b (RR-isomer) inhibited EAAT1 (IC(50) values 5.5 and 3.8 μM, respectively), whereas analogues 11b (SS-isomer) and 12a (SR-isomer) failed to inhibit EAAT1 uptake (IC(50) values >300 μM).
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Affiliation(s)
- Tri H V Huynh
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
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Cai YS, Guo YW, Krohn K. Structure, bioactivities, biosynthetic relationships and chemical synthesis of the spirodioxynaphthalenes. Nat Prod Rep 2010; 27:1840-70. [PMID: 21038061 DOI: 10.1039/c0np00031k] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- You-Sheng Cai
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Zu Chong Zhi Rd. 555, Shanghai, 201203, People's Republic of China
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9
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Bringmann G, Bruhn T, Maksimenka K, Hemberger Y. The Assignment of Absolute Stereostructures through Quantum Chemical Circular Dichroism Calculations. European J Org Chem 2009. [DOI: 10.1002/ejoc.200801121] [Citation(s) in RCA: 282] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Gerhard Bringmann
- Institute of Organic Chemistry, University of Würzburg, Am Hubland, 97074 Würzburg, Germany, Fax: +49‐931‐888‐4755
| | - Torsten Bruhn
- Institute of Organic Chemistry, University of Würzburg, Am Hubland, 97074 Würzburg, Germany, Fax: +49‐931‐888‐4755
| | - Katja Maksimenka
- Institute of Organic Chemistry, University of Würzburg, Am Hubland, 97074 Würzburg, Germany, Fax: +49‐931‐888‐4755
| | - Yasmin Hemberger
- Institute of Organic Chemistry, University of Würzburg, Am Hubland, 97074 Würzburg, Germany, Fax: +49‐931‐888‐4755
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Macías-Rubalcava ML, Hernández-Bautista BE, Jiménez-Estrada M, González MC, Glenn AE, Hanlin RT, Hernández-Ortega S, Saucedo-García A, Muria-González JM, Anaya AL. Naphthoquinone spiroketal with allelochemical activity from the newly discovered endophytic fungus Edenia gomezpompae. PHYTOCHEMISTRY 2008; 69:1185-1196. [PMID: 18234248 DOI: 10.1016/j.phytochem.2007.12.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Revised: 10/29/2007] [Accepted: 12/03/2007] [Indexed: 05/25/2023]
Abstract
Chemical investigation of the mycelium of Edenia gomezpompae, a newly discovered endophytic fungus isolated from the leaves of Callicarpa acuminata (Verbenaceae) collected from the ecological reserve El Eden, Quintana Roo, Mexico, resulted in the isolation of four naphthoquinone spiroketals, including three new compounds and palmarumycin CP2 (4). We elucidated the structures of the metabolites by extensive NMR spectroscopy studies, including DEPT, COSY, NOESY, HSQC, HMBC, and chiroptical methods. The trivial names proposed for these compounds are preussomerin EG1 (1), preussomerin EG2 (2) and preussomerin EG3 (3). In addition, the X-ray data for 4 were obtained. The bioactivity of the mycelial organic extracts and the pure compounds was tested against three endophytic fungi (Colletotrichum sp., Phomopsis sp., and Guignardia manguifera) isolated from the same plant species (C. acuminata, Verbenaceae) and against four economically important phytopathogenic microorganisms (two fungoid oomycetes, Phythophtora capsici and Phythophtora parasitica, and the fungi Fusarium oxysporum and Alternaria solani). Spiroketals 1-3 displayed significant growth inhibition against all the phytopathogens. IC50 values for the four phytopathogens were from 20 to 170 microg/ml. Palmarumycin CP2 (4) was not bioactive against any of the fungi tested. Compound 1 showed the strongest bioactivity. The acetylated derivatives of preussomerin EG1 (1), 1a and 1b, were obtained and their biological activity was tested on endophytes and phytopathogens. Preussomerin EG1 1, 1a and 1b exhibited significant bioactivity against all microorganisms tested with the exception of Alternaria solani. This is the first report of allelochemicals with antifungal activity from the newly discovered endophytic fungus E. gomezpompae.
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Affiliation(s)
- Martha L Macías-Rubalcava
- Instituto de Ecología, Departamento de Ecología Funcional, Universidad Nacional Autónoma de México, Apartado Postal 70-275, Ciudad Universitaria, 04510 Mexico DF, Mexico
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Krohn K, Kock I, Elsässer B, Flörke U, Schulz B, Draeger S, Pescitelli G, Antus S, Kurtán T. Bioactive Natural Products from the Endophytic FungusAscochyta sp. fromMeliotus dentatus – Configurational Assignment by Solid-State CD and TDDFT Calculations. European J Org Chem 2007. [DOI: 10.1002/ejoc.200600907] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Elsässer B, Krohn K, Flörke U, Root N, Aust HJ, Draeger S, Schulz B, Antus S, Kurtán T. X-ray Structure Determination, Absolute Configuration and Biological Activity of Phomoxanthone A. European J Org Chem 2005. [DOI: 10.1002/ejoc.200500265] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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13
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Elsässer B, Krohn K, Akhtar MN, Flörke U, Kouam SF, Kuigoua MG, Ngadjui BT, Abegaz BM, Antus S, Kurtán T. Revision of the Absolute Configuration of Plumericin and Isoplumericin fromPlumeria rubra. Chem Biodivers 2005; 2:799-808. [PMID: 17192024 DOI: 10.1002/cbdv.200590058] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The absolute configurations of plumericin (1) and isoplumericin (2), isolated from Plumeria rubra, were re-assigned based on a combination of X-ray crystal-structure determination and quantum-mechanical calculations of their circular dichroism (CD) spectra. The experimental CD spectra showed an excellent match with those calculated for the (1S,5R,8R,9R,10R) absolute configuration (corresponding to ent-1 and ent-2, resp.), opposite to that generally accepted and published in the literature. Since the (false) plumericin configuration has been often used to derive the absolute configuration of related iridoids by chemical correlation, their absolute configurations also have to be reconsidered.
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Affiliation(s)
- Brigitta Elsässer
- Department of Chemistry, University of Paderborn, Warburger Strasse 100, D-33098 Paderborn
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Giorgio E, Minichino C, Viglione RG, Zanasi R, Rosini C. Assignment of the molecular absolute configuration through the ab initio Hartree-Fock calculation of the optical rotation: can the circular dichroism data help in reducing basis set requirements? J Org Chem 2003; 68:5186-92. [PMID: 12816475 DOI: 10.1021/jo026867s] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this paper the calculation of the optical rotation (OR) of some rigid organic molecules, using the Hartree-Fock method with small (6-31G, DZP) basis sets, has been studied thoroughly to carefully evaluate the scope and limitations of this method, previously introduced by other authors. Calculations on test molecules (compounds 1-13) together with a careful analysis of their CD spectra allow a simple criterion for the reliability of this approach to be formulated: for unsaturated and/or aromatic (i.e., absorbing in the near-UV region) molecules, if the [alpha](D) is quantitatively determined by the lowest energy Cotton effect (at wavelengths >220 nm), then the HF/6-31G result is reliable. The usefulness of this method for the experimental organic chemist has been further demonstrated because the OR (sign and order of magnitude) of compounds 14-19 (i.e., large molecules having considerable interest in organic chemistry), which fulfill the above criterion and for which an extended basis set treatment is not feasible owing to their size, is correctly predicted.
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Affiliation(s)
- Egidio Giorgio
- Dipartimento di Chimica, Università degli Studi della Basilicata, via N. Sauro 85, 85100 Potenza, Italy
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Krohn K. Natural products derived from naphthalenoid precursors by oxidative dimerization. FORTSCHRITTE DER CHEMIE ORGANISCHER NATURSTOFFE = PROGRESS IN THE CHEMISTRY OF ORGANIC NATURAL PRODUCTS. PROGRES DANS LA CHIMIE DES SUBSTANCES ORGANIQUES NATURELLES 2003; 85:1-49. [PMID: 12602036 DOI: 10.1007/978-3-7091-6051-0_1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Affiliation(s)
- K Krohn
- Fachbereich Chemie und Chemietechnik, Universität Paderborn, Germany
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Bringmann G, Lang G. Full absolute stereostructures of natural products directly from crude extracts: The HPLC-MS/ MS-NMR-CD 'triad'. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2003; 37:89-116. [PMID: 15825641 DOI: 10.1007/978-3-642-55519-0_4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
This chapter deals with an efficient methodology available in our Center of Excellence, BIOTECmarin: the novel analytical 'triad' HPLC-MS/MS-NMR-CD. By this method, which was, in this complemented form, first introduced into phytochemical research by our group, we can not only rapidly identify known structures, but can also investigate new metabolites and establish their full absolute stereostructures online, directly from crude extracts, without the necessity of first isolating the compounds. The LC-CD option, which we have been using for the first time in natural products analysis, becomes even more valuable by the possibility of interpreting the online CD spectra by their simulation or prediction through quantum chemical calculation, thus avoiding the usual, often risky, empirical comparison with the CD spectra of (sometimes not so related) compounds of known absolute stereostructure or the application of (sometimes not really applicable) likewise empirical CD rules. The hyphenated analytical methods are additionally complemented by our synthetic expertise, again involving new concepts and strategies developed in our group. The methods and their application will first be explained and exemplified for plant-derived ('terrestrial') natural products, for which they were initially developed, and will then be applied to the online structural elucidation of novel natural products from marine organisms.
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Affiliation(s)
- G Bringmann
- Institute of Organic Chemistry, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
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Barrett AGM, Blaney F, Campbell AD, Hamprecht D, Meyer T, White AJP, Witty D, Williams DJ. Unified route to the palmarumycin and preussomerin natural products. Enantioselective synthesis of (-)-preussomerin G. J Org Chem 2002; 67:2735-50. [PMID: 11975523 DOI: 10.1021/jo0110247] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The total syntheses of eight members of the palmarumycin family have been achieved, with identification of the absolute stereochemistry for three of these natural products. In addition, the ras-farnesyl transferase inhibitor (-)-preussomerin G has been synthesized, achieving the first enantioselective route for accessing this family of natural products. Highlights of the synthetic work include an asymmetric epoxidation of a cyclic enone in excellent yield and enantiomeric excess and a potentially biomimetic oxidative spirocyclization for the introduction of the bis-spiroketal array unique to the preussomerin natural products.
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Affiliation(s)
- Anthony G M Barrett
- Department of Chemistry, Imperial College of Science, Technology and Medicine, South Kensington, London SW7 2AY, UK.
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Wang T, Shirota O, Nakanishi K, Berova N, McDonald LA, Barbieri LR, Carter GT. Absolute stereochemistry of the spiroxins. CAN J CHEM 2001. [DOI: 10.1139/v01-153] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The absolute configuration of spiroxin A has been determined by exciton-coupled circular dichroism (CD). Namely, the difference CD between spiroxin A bis-methoxycinnamate, as well as that between spiroxin A bis-retinoate, both exhibit negative exciton couplings between the acylated phenolic hydroxyl group chromophores. This establishes the absolute configuration as 2S,3R,4S,2'S,3'R,4'S.Key words: circular dichroism, exciton coupling, spiroxins, antitumor, antifungal.
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Krohn K, Steingröver K, Zsila F. The absolute configuration of the palmarumycins C9, C10, and C12 by quantum-mechanical calculations of CD spectra. ACTA ACUST UNITED AC 2001. [DOI: 10.1016/s0957-4166(01)00365-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Krohn K, Flörke U, John M, Root N, Steingröver K, Aust HJ, Draeger S, Schulz B, Antus S, Simonyi M, Zsila F. Biologically active metabolites from fungi. Part 16: New preussomerins J, K and L from an endophytic fungus: structure elucidation, crystal structure analysis and determination of absolute configuration by CD calculations. Tetrahedron 2001. [DOI: 10.1016/s0040-4020(01)00320-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Bode HB, Zeeck A. UV mutagenesis and enzyme inhibitors as tools to elucidate the late biosynthesis of the spirobisnaphthalenes. PHYTOCHEMISTRY 2000; 55:311-316. [PMID: 11117878 DOI: 10.1016/s0031-9422(00)00307-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The metabolite pattern of UV mutants of the spirobisnaphthalene producing fungus F-24'707 by TLC and HPLC analysis has been investigated. Mutants with differences in colony morphology or colour compared to the parent strain were isolated. Cultivation in shaking flasks and P flasks showed differences in the metabolite pattern of some of the strains. Furthermore, enzyme inhibitors were used to block the spirobisnaphthalene biosynthesis of the parent strain at different steps. Feeding of precursors and intermediates of cladospirone bisepoxide (15) led to a two-fold increase of the production of 15. From these data and preceding biosynthetic studies we deduced a general pathway for the biosynthesis of all spirobisnaphthalenes of the fungus F-24'707. This enables us to present the hypothesis that all bisnaphthalenes described so far are produced using a common pathway with only a few intermediates as central branching points.
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Affiliation(s)
- H B Bode
- Institut für Organische Chemie, Universität Göttingen, Germany
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Bioactive metabolites from soilborne fungi: natural fungicides and biocontrol agents. ACTA ACUST UNITED AC 2000. [DOI: 10.1016/s1572-5995(00)80007-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Bringmann G, Kraus J, Menche D, Messer K. Elucidation of the absolute configuration of knipholone and knipholone anthrone by quantum chemical CD calculations. Tetrahedron 1999. [DOI: 10.1016/s0040-4020(99)00391-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Ziegler M. Charge-transfer excited state properties of chiral transition metal coordination compounds studied by chiroptical spectroscopy. Coord Chem Rev 1998. [DOI: 10.1016/s0010-8545(98)00186-6] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Krohn K, Beckmann K, Aust HJ, Draeger S, Schulz B, Busemann S, Bringmann G. Biologically Active Metabolites from Fungi, 10. Generation of the Palmarumycin Spiroacetal Framework by Oxidative Cyclization of an Open Chain Metabolite fromConiothyrium palmarum. ACTA ACUST UNITED AC 1997. [DOI: 10.1002/jlac.199719971216] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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