1
|
Li L, Wang Y, Chen N, Li X, Li H, Jin L, Ou Y, Kong XJ, Cao S, Xu Q, Wu X, Han J, Deng X. Exploring Diversity through Dimerization in Natural Products by a Rational Tandem Mass-Based Molecular Network Strategy. Org Lett 2023; 25:4016-4021. [PMID: 37249258 DOI: 10.1021/acs.orglett.3c01038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The step- and atom-efficient dimerization strategy is frequently used in nature to build structural complexity and diversity. We propose the rationale and structural features of the versatile monomers that are responsible for "diversity through dimerization". Using 5-FAM-maleimide combined with a UHPLC-MS/MS-FBMN workflow, we successfully identified a diverse set of dimeric natural products from fungus Panus rudis F01315, in which all four complex 4'5-ring scaffolds are derived from one monomeric epoxyquinol and endowed with functional diversity.
Collapse
Affiliation(s)
- Li Li
- State Key Laboratory of Cellular Stress Biology, State-province Joint Engineering Laboratory of Targeted Drugs from Natural Products, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Yuezhou Wang
- State Key Laboratory of Cellular Stress Biology, State-province Joint Engineering Laboratory of Targeted Drugs from Natural Products, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Naixin Chen
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Xiaoyang Li
- State Key Laboratory of Cellular Stress Biology, State-province Joint Engineering Laboratory of Targeted Drugs from Natural Products, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Hanpeng Li
- State Key Laboratory of Cellular Stress Biology, State-province Joint Engineering Laboratory of Targeted Drugs from Natural Products, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Ling Jin
- State Key Laboratory of Cellular Stress Biology, State-province Joint Engineering Laboratory of Targeted Drugs from Natural Products, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Yixin Ou
- State Key Laboratory of Cellular Stress Biology, State-province Joint Engineering Laboratory of Targeted Drugs from Natural Products, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Xiang-Jian Kong
- Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
| | - Shugeng Cao
- Department of Pharmaceutical Sciences, Daniel K. Inouye College of Pharmacy, University of Hawai'i at Hilo, 200 W. Kawili St., Hilo, Hawaii 96720, USA
| | - Qingyan Xu
- State Key Laboratory of Cellular Stress Biology, State-province Joint Engineering Laboratory of Targeted Drugs from Natural Products, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Xiaobing Wu
- State Key Laboratory of Cellular Stress Biology, State-province Joint Engineering Laboratory of Targeted Drugs from Natural Products, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Jianyong Han
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Xianming Deng
- State Key Laboratory of Cellular Stress Biology, State-province Joint Engineering Laboratory of Targeted Drugs from Natural Products, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| |
Collapse
|
2
|
Burns DC, Reynolds WF. Minimizing the risk of deducing wrong natural product structures from NMR data. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2021; 59:500-533. [PMID: 33855734 DOI: 10.1002/mrc.4933] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 07/31/2019] [Accepted: 08/01/2019] [Indexed: 06/12/2023]
Abstract
There continues to be a disturbing number of natural products reported in the literature whose structures are incorrect. At least in part, this reflects the fact that many natural product chemists have limited formal nuclear magnetic resonance training. Gaps in training and lack of awareness regarding the challenges and ambiguities associated with two-dimensional nuclear magnetic resonance data interpretation can easily lead to errors in structure elucidation. The purpose of this tutorial is to point out some of these issues, highlight the kinds of errors that have been made and provide specific advice on how to avoid these missteps such that the risk of reporting a wrong structure is minimized.
Collapse
Affiliation(s)
- Darcy C Burns
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - William F Reynolds
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
| |
Collapse
|
3
|
Costa FLP, de Albuquerque ACF, Fiorot RG, Lião LM, Martorano LH, Mota GVS, Valverde AL, Carneiro JWM, dos Santos Junior FM. Structural characterisation of natural products by means of quantum chemical calculations of NMR parameters: new insights. Org Chem Front 2021. [DOI: 10.1039/d1qo00034a] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
In this review, we focus in all aspects of NMR simulation of natural products, from the fundamentals to the new computational toolboxes available, combining advanced quantum chemical calculations with upstream data processing and machine learning.
Collapse
Affiliation(s)
| | - Ana C. F. de Albuquerque
- Departamento de Química Orgânica
- Instituto de Química
- Universidade Federal Fluminense
- Niterói-RJ
- Brazil
| | - Rodolfo G. Fiorot
- Departamento de Química Orgânica
- Instituto de Química
- Universidade Federal Fluminense
- Niterói-RJ
- Brazil
| | - Luciano M. Lião
- Instituto de Química
- Universidade Federal de Goiás
- 74690-900 Goiânia-GO
- Brazil
| | - Lucas H. Martorano
- Departamento de Química Orgânica
- Instituto de Química
- Universidade Federal Fluminense
- Niterói-RJ
- Brazil
| | - Gunar V. S. Mota
- Faculdade de Ciências Naturais/Instituto de Ciências Exatas e Naturais
- Universidade Federal do Pará
- Belém-PA
- Brazil
| | - Alessandra L. Valverde
- Departamento de Química Orgânica
- Instituto de Química
- Universidade Federal Fluminense
- Niterói-RJ
- Brazil
| | - José W. M. Carneiro
- Departamento de Química Inorgânica
- Instituto de Química
- Universidade Federal Fluminense
- Niterói-RJ
- Brazil
| | | |
Collapse
|
4
|
Theoretical prediction of 13C NMR spectrum of mixed triglycerides by mean of GIAO calculations to improve vegetable oils analysis. Chem Phys Lipids 2020; 232:104973. [PMID: 32926853 DOI: 10.1016/j.chemphyslip.2020.104973] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 08/17/2020] [Accepted: 09/04/2020] [Indexed: 01/11/2023]
Abstract
This pioneering study based on GIAO-DFT methods is aimed to the best prediction of 13C Nuclear Magnetic Resonances (NMR) arising from triglycerides (and also glycerols), known to be the main component of vegetable oils. Provided that fatty esters bound to the glycerol moiety are not affected by the other esterification chains, and slightly affected by their own esterification position (2- internal, or 1/3- external), eight natural molecules are first optimized despite the challenging presence of many non-hydrogen atoms and the large conformational freedom. This preliminary study sheds light on the total chemical shift prediction concerning five fatty esters (Oleic, Palmitic, Linoleic, Stearic and Linolenic) either present in internal or external positions (ten fragments in total); these results display a very good matching to the experimental profile recorded for several vegetable oils chosen as natural mixtures of glycerides. In order to further improve the theoretical to experimental matching, ten simplified triglycerides with the mentioned fatty esters in the two different esterification positions, and flanked by acetyl esters, were studied and optimized. Beyond the best matching reached so far, we notice that the theoretical rationalisation of the overcrowding in the 28.7-29 ppm spectral region in unable to decode the necessary resolution, nonetheless the same theoretical prediction can still drive the appropriate assignments (as for the fifth and sixth carbon attribution of every chain) even against actual misleading reports.
Collapse
|
5
|
Abstract
We describe the total synthesis of epoxyquinoid natural products (+)-pestalofone A and (+)-iso-A82775C. The synthesis of (+)-16-oxo-iso-A82775C, the putative biosynthetic precursor of pestalofone C, is also presented. The allene moiety present in (+)-iso-A82775C and (+)-16-oxo-iso-A82775C was constructed from the ketodiene-yne group via a biosynthetically relevant sequence involving a conjugate reduction and a base-catalyzed tautomerization. Attempted Diels-Alder reaction-based dimerizations of (+)-16-oxo-iso-A82775C and (+)-iso-A82775C toward pestalofones B and C are also described.
Collapse
Affiliation(s)
- Geon Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Taewan Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Sunkyu Han
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| |
Collapse
|
6
|
Kaur N, Ahlawat N, Verma Y, Grewal P, Bhardwaj P, Jangid NK. Metal and organo-complex promoted synthesis of fused five-memberedO-heterocycles. SYNTHETIC COMMUN 2019. [DOI: 10.1080/00397911.2019.1700522] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Navjeet Kaur
- Department of Chemistry, Banasthali Vidyapith, Banasthali, India
| | - Neha Ahlawat
- Department of Chemistry, Banasthali Vidyapith, Banasthali, India
| | - Yamini Verma
- Department of Chemistry, Banasthali Vidyapith, Banasthali, India
| | - Pooja Grewal
- Department of Chemistry, Banasthali Vidyapith, Banasthali, India
| | - Pranshu Bhardwaj
- Department of Chemistry, Banasthali Vidyapith, Banasthali, India
| | | |
Collapse
|
7
|
Kutateladze AG, Holt T, Reddy DS. Natural Products Containing the Oxetane and Related Moieties Present Additional Challenges for Structure Elucidation: A DU8+ Computational Case Study. J Org Chem 2019; 84:7575-7586. [DOI: 10.1021/acs.joc.9b01005] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Andrei G. Kutateladze
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| | - Tina Holt
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| | - D. Sai Reddy
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| |
Collapse
|
8
|
Tantillo DJ. Questions in natural products synthesis research that can (and cannot) be answered using computational chemistry. Chem Soc Rev 2018; 47:7845-7850. [PMID: 29900461 PMCID: PMC6205925 DOI: 10.1039/c8cs00298c] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Questions of relevance to those working in the field of natural products synthesis that can be answered, at least in part, using computational chemistry approaches are described. Illustrative examples are provided, as are descriptions of limitations.
Collapse
Affiliation(s)
- Dean J Tantillo
- Department of Chemistry, University of California - Davis, Davis, CA 95616, USA.
| |
Collapse
|
9
|
Kim G, Kim MJ, Chung G, Lee HY, Han S. (+)-Dimericbiscognienyne A: Total Synthesis and Mechanistic Investigations of the Key Heterodimerization. Org Lett 2018; 20:6886-6890. [DOI: 10.1021/acs.orglett.8b03025] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Geon Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, Korea
| | - Myungjo J. Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Garam Chung
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, Korea
| | - Hee-Yoon Lee
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Sunkyu Han
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, Korea
| |
Collapse
|
10
|
Kutateladze AG, Kuznetsov DM, Beloglazkina AA, Holt T. Addressing the Challenges of Structure Elucidation in Natural Products Possessing the Oxirane Moiety. J Org Chem 2018; 83:8341-8352. [DOI: 10.1021/acs.joc.8b01027] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Andrei G. Kutateladze
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| | - Dmitry M. Kuznetsov
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| | | | - Tina Holt
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| |
Collapse
|
11
|
Schmiedel VM, Hong YJ, Lentz D, Tantillo DJ, Christmann M. Synthesis and Structure Revision of Dichrocephones A and B. Angew Chem Int Ed Engl 2018; 57:2419-2422. [DOI: 10.1002/anie.201711766] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Indexed: 11/12/2022]
Affiliation(s)
- Volker M. Schmiedel
- Freie Universität Berlin; Institute of Chemistry and Biochemistry; Takustr. 3 14195 Berlin Germany
| | - Young J. Hong
- Department of Chemistry; University of California, Davis; One Shields Avenue Davis CA 95616 USA
| | - Dieter Lentz
- Freie Universität Berlin; Institute of Chemistry and Biochemistry; Takustr. 3 14195 Berlin Germany
| | - Dean J. Tantillo
- Department of Chemistry; University of California, Davis; One Shields Avenue Davis CA 95616 USA
| | - Mathias Christmann
- Freie Universität Berlin; Institute of Chemistry and Biochemistry; Takustr. 3 14195 Berlin Germany
| |
Collapse
|
12
|
Schmiedel VM, Hong YJ, Lentz D, Tantillo DJ, Christmann M. Synthesis and Structure Revision of Dichrocephones A and B. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201711766] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Volker M. Schmiedel
- Freie Universität Berlin; Institute of Chemistry and Biochemistry; Takustr. 3 14195 Berlin Germany
| | - Young J. Hong
- Department of Chemistry; University of California, Davis; One Shields Avenue Davis CA 95616 USA
| | - Dieter Lentz
- Freie Universität Berlin; Institute of Chemistry and Biochemistry; Takustr. 3 14195 Berlin Germany
| | - Dean J. Tantillo
- Department of Chemistry; University of California, Davis; One Shields Avenue Davis CA 95616 USA
| | - Mathias Christmann
- Freie Universität Berlin; Institute of Chemistry and Biochemistry; Takustr. 3 14195 Berlin Germany
| |
Collapse
|
13
|
Iron MA. Evaluation of the Factors Impacting the Accuracy of 13C NMR Chemical Shift Predictions using Density Functional Theory-The Advantage of Long-Range Corrected Functionals. J Chem Theory Comput 2017; 13:5798-5819. [PMID: 29016125 DOI: 10.1021/acs.jctc.7b00772] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The various factors influencing the accuracy of 13C NMR calculations using density functional theory (DFT), including the basis set, exchange-correlation (XC) functional, and isotropic shielding calculation method, are evaluated. A wide selection of XC functionals (over 70) were considered, and it was found that long-range corrected functionals offer a significant improvement over the other classes of functionals. Based on a thorough study, it is recommended that for calculating NMR chemical shifts (δ) one should use the CSGT method, the COSMO solvation model, and the LC-TPSSTPSS exchange-correlation functional in conjunction with the cc-pVTZ basis set. A selection of problems in natural product identification are considered in light of the newly recommended level of theory.
Collapse
Affiliation(s)
- Mark A Iron
- Computational Chemistry Unit, Department of Chemical Research Support, Weizmann Institute of Science , Rehovot 7610001, Israel
| |
Collapse
|
14
|
Mehta G, Sengupta S. Progress in the total synthesis of epoxyquinone natural products: An update. Tetrahedron 2017. [DOI: 10.1016/j.tet.2017.09.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
15
|
Zhao ZZ, Chen HP, Wu B, Zhang L, Li ZH, Feng T, Liu JK. Matsutakone and Matsutoic Acid, Two (Nor)steroids with Unusual Skeletons from the Edible Mushroom Tricholoma matsutake. J Org Chem 2017; 82:7974-7979. [PMID: 28691489 DOI: 10.1021/acs.joc.7b01230] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zhen-Zhu Zhao
- State
Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - He-Ping Chen
- School
of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan 430074, P. R. China
- State
Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, P. R. China
| | - Bin Wu
- School
of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan 430074, P. R. China
| | - Ling Zhang
- State
Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, P. R. China
| | - Zheng-Hui Li
- School
of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan 430074, P. R. China
| | - Tao Feng
- School
of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan 430074, P. R. China
| | - Ji-Kai Liu
- School
of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan 430074, P. R. China
| |
Collapse
|
16
|
Secondary Metabolites from Higher Fungi. PROGRESS IN THE CHEMISTRY OF ORGANIC NATURAL PRODUCTS 106 2017; 106:1-201. [DOI: 10.1007/978-3-319-59542-9_1] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
17
|
|
18
|
Jogalekar AS. Social Media, Peer Review, and Responsible Conduct of Research (RCR) in Chemistry: Trends, Pitfalls, and Promises. Account Res 2015; 22:402-30. [PMID: 26155733 PMCID: PMC4714242 DOI: 10.1080/08989621.2015.1047705] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Over the last two decades, various themes inherent in the responsible conduct of research (RCR) in chemistry have been brought to light through prominent cases of research misconduct. This article will describe a few of these cases especially through the lens of social media such as blogs and Twitter. A case will be made that these wholly novel modalities of online discussion are now complementing, and in some cases even circumventing some of the limitations of traditional peer review in chemistry. We present in detail our evaluation of three recent cases of RCR along with several other social media illustrations. These cases have been selected to be representative and showcase several of the most prominent issues at the intersection of traditional and social-media based peer review. In each case, basic details are presented along with a brief discussion of the underlying issues-readers interested in deeper analysis of each subject are referred to a collection of relevant articles and websites. This perspective focuses on the most important RCR issues that have arisen in the past decade, a time which we believe coincides with the serious participation of the scientific community in general, and the chemistry community in particular, in social media-based, citizen-enabled peer-review. A discussion of important trends in RCR in the age of social media, outstanding developments in this area, and questions of enduring interest for the near future concludes the article.
Collapse
Affiliation(s)
- Ashutosh S. Jogalekar
- Address correspondence to Ashutosh S. Jogalekar, 284 Harvard Street, Apartment 42, Cambridge, MA02139, USA. E-mail:
| |
Collapse
|
19
|
Reynolds WF, Mazzola EP. Nuclear magnetic resonance in the structural elucidation of natural products. PROGRESS IN THE CHEMISTRY OF ORGANIC NATURAL PRODUCTS 2015; 100:223-309. [PMID: 25632562 DOI: 10.1007/978-3-319-05275-5_3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
|
20
|
Abstract
Cyclohexadienones are versatile platforms for performing asymmetric synthesis as evidenced by the numerous natural product syntheses that exploit their diverse reactivity profile. However, there are few general methods available for the direct asymmetric synthesis of chiral cyclohexadienones. To circumvent this problem, several researchers have developed catalytic asymmetric methods that employ readily available achiral 2,5-cyclohexadienones as substrates. Many of these reactions are desymmetrizations in which one of the enantiotopic alkenes of an achiral dienone is transformed. Others involve selective reaction at one alkene of an unsymmetrically substituted, achiral dienone. This review will cover advances in this area over the last 20 years and the application of these strategies in complex molecule synthesis.
Collapse
Affiliation(s)
- Kyle A Kalstabakken
- Department of Chemistry, University of Minnesota-Twin Cities, 207 Pleasant St SE, Minneapolis, Minnesota 55455, United States
| | - Andrew M Harned
- Department of Chemistry, University of Minnesota-Twin Cities, 207 Pleasant St SE, Minneapolis, Minnesota 55455, United States
| |
Collapse
|
21
|
A guide to small-molecule structure assignment through computation of (¹H and ¹³C) NMR chemical shifts. Nat Protoc 2014; 9:643-60. [PMID: 24556787 DOI: 10.1038/nprot.2014.042] [Citation(s) in RCA: 299] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This protocol is intended to provide chemists who discover or make new organic compounds with a valuable tool for validating the structural assignments of those new chemical entities. Experimental ¹H and/or ¹³C NMR spectral data and its proper interpretation for the compound of interest is required as a starting point. The approach involves the following steps: (i) using molecular mechanics calculations (with, e.g., MacroModel) to generate a library of conformers; (ii) using density functional theory (DFT) calculations (with, e.g., Gaussian 09) to determine optimal geometry, free energies and chemical shifts for each conformer; (iii) determining Boltzmann-weighted proton and carbon chemical shifts; and (iv) comparing the computed chemical shifts for two or more candidate structures with experimental data to determine the best fit. For a typical structure assignment of a small organic molecule (e.g., fewer than ∼10 non-H atoms or up to ∼180 a.m.u. and ∼20 conformers), this protocol can be completed in ∼2 h of active effort over a 2-d period; for more complex molecules (e.g., fewer than ∼30 non-H atoms or up to ∼500 a.m.u. and ∼50 conformers), the protocol requires ∼3-6 h of active effort over a 2-week period. To demonstrate the method, we have chosen the analysis of the cis- versus the trans-diastereoisomers of 3-methylcyclohexanol (1-cis versus 1-trans). The protocol is written in a manner that makes the computation of chemical shifts tractable for chemists who may otherwise have only rudimentary computational experience.
Collapse
|
22
|
Song L, Lee KH, Lin Z, Tong R. Structural revision of cephalosporolide J and bassianolone. J Org Chem 2014; 79:1493-7. [PMID: 24417265 DOI: 10.1021/jo402602h] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The NMR spectra for three "natural" products: cephalosporolide C (Ces-C), cephalosporolide J (Ces-J), and bassianolone were found to be identical, and we proposed that Ces-C was the correct structure for the reported spectra. The first total synthesis of the proposed structure for Ces-J was achieved to support our structural revision for Ces-J. Chemical transformations of bassianolone and computational prediction of (13)C NMR spectra allowed us to conclude that Ces-C was the correct structure for bassianolone. Our synthetic and computational studies suggested that these "different" natural products Ces-C, Ces-J, and bassianolone have the same structure: Ces-C.
Collapse
Affiliation(s)
- Liyan Song
- Department of Chemistry, The Hong Kong University of Science and Technology , Clear Water Bay, Kowloon, Hong Kong, China
| | | | | | | |
Collapse
|
23
|
Studies in the Synthesis of Biaryl Natural Products. ACTA ACUST UNITED AC 2014. [DOI: 10.1016/b978-0-12-417185-5.00010-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|
24
|
Vannada J, Niehues L, König B, Mehta G. A total synthesis of the epoxyquinone natural product cytosporin D. Tetrahedron 2013. [DOI: 10.1016/j.tet.2013.05.075] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
25
|
Tantillo DJ. Walking in the woods with quantum chemistry--applications of quantum chemical calculations in natural products research. Nat Prod Rep 2013; 30:1079-86. [PMID: 23793561 DOI: 10.1039/c3np70028c] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
This Highlight describes applications of quantum chemical calculations to problems in natural products chemistry, including the elucidation of natural product structures (distinguishing between constitutional isomers, distinguishing between diastereomers, and assigning absolute configuration) and determination of reasonable mechanisms for their formation.
Collapse
Affiliation(s)
- Dean J Tantillo
- Department of Chemistry, University of California-Davis, 1 Shields Avenue, Davis, CA, USA.
| |
Collapse
|
26
|
Abstract
Over the past 28 years there have been several thousand publications describing the use of 2D NMR to identify and characterize natural products. During this time period, the amount of sample needed for this purpose has decreased from the 20-50 mg range to under 1 mg. This has been due to both improvements in NMR hardware and methodology. This review will focus on mainly methodology improvements, particularly in pulse sequences, acquisition and processing methods which are particularly relevant to natural product research, with lesser discussion of hardware improvements.
Collapse
|
27
|
Liermann JC, Elnagdi MH, Meier H. Unambiguous structure elucidation of heterocyclic products from condensation-cyclisation reactions of enaminones by 2D INADEQUATE and 15N NMR. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2013; 51:16-18. [PMID: 23132629 DOI: 10.1002/mrc.3897] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 10/06/2012] [Accepted: 10/11/2012] [Indexed: 06/01/2023]
Abstract
The reaction of enaminones with 3-amino-2-cyanopent-2-enedinitrile can lead to an array of 12 possible products, depending on the reaction pathway and tautomerization. The use of 2D INADEQUATE and (15)N NMR for the unambiguous structure elucidation of the reaction products is discussed in this manuscript.
Collapse
Affiliation(s)
- Johannes C Liermann
- Institut für Organische Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128, Mainz, Germany.
| | | | | |
Collapse
|
28
|
Sarotti AM. Successful combination of computationally inexpensive GIAO 13C NMR calculations and artificial neural network pattern recognition: a new strategy for simple and rapid detection of structural misassignments. Org Biomol Chem 2013; 11:4847-59. [DOI: 10.1039/c3ob40843d] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
|
29
|
O’Byrne A, O’Reilly S, Tighe C, Evans P, Ciuffini L, Gabriella Santoro M. Temporary thio-derivatization in the synthesis of (+)-4-acetylbromoxone. Tetrahedron Lett 2012. [DOI: 10.1016/j.tetlet.2012.08.101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
30
|
Mehta G, Roy S, Pan SC. Enantioselective syntheses of bioactive epoxyquinone natural products (+)-harveynone and (−)-asperpentyn. Tetrahedron Lett 2012. [DOI: 10.1016/j.tetlet.2012.05.115] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
31
|
Affiliation(s)
- Dimitris Noutsias
- Department of Chemistry, University of Crete, Vasilika Vouton, 71003 Iraklion, Crete, Greece
| | | |
Collapse
|
32
|
Lodewyk MW, Siebert MR, Tantillo DJ. Computational prediction of 1H and 13C chemical shifts: a useful tool for natural product, mechanistic, and synthetic organic chemistry. Chem Rev 2011; 112:1839-62. [PMID: 22091891 DOI: 10.1021/cr200106v] [Citation(s) in RCA: 897] [Impact Index Per Article: 69.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Michael W Lodewyk
- Department of Chemistry, University of California-Davis, Davis, California 95616, USA
| | | | | |
Collapse
|
33
|
Lodewyk MW, Tantillo DJ. Prediction of the structure of nobilisitine a using computed NMR chemical shifts. JOURNAL OF NATURAL PRODUCTS 2011; 74:1339-1343. [PMID: 21469691 DOI: 10.1021/np2000446] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
1H and 13C NMR computed chemical shifts are determined for eight diastereomers of the originally proposed structure of nobilisitine A, which has recently been shown to be incorrect. On the basis of comparison of the computed chemical shifts with those reported experimentally, we predict that the true structure of nobilisitine A is likely the diastereomer shown here or its enantiomer.
Collapse
Affiliation(s)
- Michael W Lodewyk
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
| | | |
Collapse
|
34
|
Clayden J, MacLellan P. Asymmetric synthesis of tertiary thiols and thioethers. Beilstein J Org Chem 2011; 7:582-95. [PMID: 21647256 PMCID: PMC3107483 DOI: 10.3762/bjoc.7.68] [Citation(s) in RCA: 168] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Accepted: 04/15/2011] [Indexed: 11/23/2022] Open
Abstract
Enantiomerically pure tertiary thiols provide a major synthetic challenge, and despite the importance of chiral sulfur-containing compounds in biological and medicinal chemistry, surprisingly few effective methods are suitable for the asymmetric synthesis of tertiary thiols. This review details the most practical of the methods available.
Collapse
Affiliation(s)
- Jonathan Clayden
- School of Chemistry, University of Manchester, Oxford Rd, Manchester M13 9PL, UK
| | - Paul MacLellan
- School of Chemistry, University of Manchester, Oxford Rd, Manchester M13 9PL, UK
| |
Collapse
|
35
|
Clay DR, Rosenberg AG, McIntosh MC. Efficient, scalable asymmetric synthesis of an epoxy quinol via Noyori desymmetrization of a meso diketone. TETRAHEDRON, ASYMMETRY 2011; 22:713-716. [PMID: 21743778 PMCID: PMC3131412 DOI: 10.1016/j.tetasy.2011.04.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Epoxy quinol 1a was prepared on a multi-gram scale by Noyori transfer hydrogenative desymmetrization of the readily available meso epoxy diketone 4. Although the intrinsic enantioselectivity for the desymmetrization was modest (82:18 er at 4% conversion), a highly enantiopure product (99.6:0.4 er) could be obtained in one operation in 44% yield via kinetic resolution of the minor enantiomer with long reaction times (48 h), or in 73% yield by combination with an enzymatic resolution of a 93:7 er mixture.
Collapse
Affiliation(s)
- David R. Clay
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA
| | - Ashley G. Rosenberg
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA
| | - Matthias C. McIntosh
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA
| |
Collapse
|
36
|
Hookins DR, Taylor RJ. A double oxidation procedure for the preparation of halogen-substituted para-benzoquinone monoketals: asymmetric synthesis of (−)-harveynone. Tetrahedron Lett 2010. [DOI: 10.1016/j.tetlet.2010.10.047] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
37
|
Gong YN, Wang X, Wang J, Yang Z, Li S, Yang J, Liu L, Lei X, Shao F. Chemical probing reveals insights into the signaling mechanism of inflammasome activation. Cell Res 2010; 20:1289-305. [PMID: 20856264 DOI: 10.1038/cr.2010.135] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Caspase-1-mediated IL-1β production is generally controlled by two pathways. Toll-like receptors (TLRs) recognize pathogen-derived products and induce NF-κB-dependent pro-IL-1β transcription; NOD-like receptors (NLRs) assemble caspase-1-activating inflammasome complexes that sense bacterial products/danger signals. Through a targeted chemical screen, we identify bromoxone, a marine natural product, as a specific and potent inhibitor of the caspase-1 pathway. Bromoxone is effective over diverse inflammatory stimuli including TLR ligands plus ATP/nigericin, cytosolic DNA, flagellin and Bacillus anthracis lethal toxin. Bromoxone also efficiently suppresses caspase-1 activation triggered by several types of bacterial infection. Bromoxone acts upstream or at the level of the inflammasome in a transcription-independent manner. Bromoxone also inhibits pro-IL-1β expression by targeting components upstream of IKK in the TLR-NF-κB pathway. The unique dual activities of bromoxone are shared by the known TAK1 inhibitor that specifically blocks Nalp3 inflammasome activation. Hinted from the mechanistic and pharmacological properties of bromoxone, we further discover that several known NF-κB inhibitors that act upstream of IKK, but not those targeting IKK or IKK downstream, are potent blockers of different NLRs-mediated caspase-1 activation. Our study uncovers a possible non-transcriptional molecular link between the NLR (Nalp3)-mediated inflammasome pathway and TLR-NF-κB signaling, and suggests a potential strategy to develop new anti-inflammatory drugs.
Collapse
Affiliation(s)
- Yi-Nan Gong
- College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Affiliation(s)
- Jingwei Li
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607, USA
| | | |
Collapse
|
39
|
Jin MY, Hwang GS, Chae HI, Jung SH, Ryu DH. Highly Efficient Synthesis of (+)-Bromoxone, (+)-Epiepoxydon and (+)-Epiepoformin. B KOREAN CHEM SOC 2010. [DOI: 10.5012/bkcs.2010.31.03.727] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
40
|
|
41
|
Yamakoshi H, Shibuya M, Tomizawa M, Osada Y, Kanoh N, Iwabuchi Y. Total Synthesis and Determination of the Absolute Configuration of (−)-Idesolide. Org Lett 2010; 12:980-3. [DOI: 10.1021/ol9029676] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hiroyuki Yamakoshi
- Department of Organic Chemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Aobayama, Sendai 980-8578, Japan
| | - Masatoshi Shibuya
- Department of Organic Chemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Aobayama, Sendai 980-8578, Japan
| | - Masaki Tomizawa
- Department of Organic Chemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Aobayama, Sendai 980-8578, Japan
| | - Yuji Osada
- Department of Organic Chemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Aobayama, Sendai 980-8578, Japan
| | - Naoki Kanoh
- Department of Organic Chemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Aobayama, Sendai 980-8578, Japan
| | - Yoshiharu Iwabuchi
- Department of Organic Chemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Aobayama, Sendai 980-8578, Japan
| |
Collapse
|
42
|
Simon O, Reux B, La Clair J, Lear M. Total Synthesis Confirms Laetirobin as a Formal Diels-Alder Adduct. Chem Asian J 2010; 5:342-51. [DOI: 10.1002/asia.200900306] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
43
|
Labora M, Pandolfi EM, Schapiro V. Efficient enantiodivergent total synthesis of (+) and (−)-bromoxone. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/j.tetasy.2009.12.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
44
|
Pinkerton DM, Banwell MG, Willis AC. (+)-hexacyclinol. Acta Crystallogr Sect E Struct Rep Online 2010; 66:o342-3. [PMID: 21579771 PMCID: PMC2979687 DOI: 10.1107/s1600536810000620] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2010] [Accepted: 01/06/2010] [Indexed: 11/10/2022]
Abstract
A SAMPLE OF THE TITLE COMPOUND [SYSTEMATIC NAME: (1aS,2aS,3S,5aS,6aS,7R,7aS,7bS,8R,8aS,10R)-7-hydr-oxy-3-(1-meth-oxy-1-methyl-ethyl)-10-(2-methyl-1-propen-yl)-1a,5a,6a,7,7a,7b,8,8a-octa-hydro-2H-8,2a-(epoxy-methano)phenanthro[2,3-b:6,7-b']bis-oxirene-2,5(3H)-dione], C(23)H(28)O(7), was generated by enanti-oselective synthesis. There are three mol-ecules of the compound in the crystallographic asymmetric unit. Hydrogen bonding between alcohol H atoms and keto groups of adjacent mol-ecules appears to stabilize the structure. The compound is enanti-omerically pure but the absolute configuration could not be determined directly in this study. Accordingly, the illustrated configuration was assigned on the basis of the nature of the chiral nonracemic precursor used in the synthesis.
Collapse
Affiliation(s)
- David M Pinkerton
- Research School of Chemistry, Institute of Advanced Studies, The Australian National University, Canberra, ACT 0200, Australia
| | | | | |
Collapse
|
45
|
Elyashberg M, Williams AJ, Blinov K. Structural revisions of natural products by Computer-Assisted Structure Elucidation (CASE) systems. Nat Prod Rep 2010; 27:1296-328. [DOI: 10.1039/c002332a] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
46
|
Pinkerton DM, Banwell MG, Willis AC. Chemoenzymatic Access to Versatile Epoxyquinol Synthons. Org Lett 2009; 11:4290-3. [DOI: 10.1021/ol9016657] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- David M. Pinkerton
- Research School of Chemistry, Institute of Advanced Studies, The Australian National University, Canberra, ACT 0200, Australia
| | - Martin G. Banwell
- Research School of Chemistry, Institute of Advanced Studies, The Australian National University, Canberra, ACT 0200, Australia
| | - Anthony C. Willis
- Research School of Chemistry, Institute of Advanced Studies, The Australian National University, Canberra, ACT 0200, Australia
| |
Collapse
|
47
|
Corminboeuf O, Overman LE, Pennington LD. A unified strategy for enantioselective total synthesis of cladiellin and briarellin diterpenes: total synthesis of briarellins E and F and the putative structure of alcyonin and revision of its structure assignment. J Org Chem 2009; 74:5458-70. [PMID: 19534538 PMCID: PMC2744073 DOI: 10.1021/jo9010156] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Enantioselective total syntheses of briarellin E (12) and briarellin F (13), as well as the structure originally proposed for the cladiellin diterpene alcyonin (10), have been realized. Comparison of the spectral data for synthetic 10, natural alcyonin, cladiellisin (33), and cladiellaperoxide (34), as well as chemical transformations of 10 and natural alcyonin, suggest that the structure of this coral metabolite is allylic peroxide 11. The unified approach detailed herein can be used to access both C4-deoxygenated and C4-oxygenated cladiellins and briarellins. The central step in these syntheses is acid-promoted condensation of (Z)-alpha,beta-unsaturated aldehydes 17 with cyclohexadienyl diols 18 to form intermediates 16 incorporating the hexahydroisobenzofuran core and five stereocenters of these marine diterpenes (Scheme 1 ).
Collapse
Affiliation(s)
| | - Larry E. Overman
- Department of Chemistry, 1102 Natural Sciences II, University of California, Irvine, California 92697-2025
| | | |
Collapse
|
48
|
Arkoudis E, Lykakis IN, Gryparis C, Stratakis M. Biomimetic Synthesis of Dimeric Metabolite Acremine G via a Highly Regioselective and Stereoselective Diels−Alder Reaction. Org Lett 2009; 11:2988-91. [DOI: 10.1021/ol901004e] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Elias Arkoudis
- Department of Chemistry, University of Crete, Voutes 71003 Iraklion, Greece
| | - Ioannis N. Lykakis
- Department of Chemistry, University of Crete, Voutes 71003 Iraklion, Greece
| | - Charis Gryparis
- Department of Chemistry, University of Crete, Voutes 71003 Iraklion, Greece
| | - Manolis Stratakis
- Department of Chemistry, University of Crete, Voutes 71003 Iraklion, Greece
| |
Collapse
|
49
|
Bräse S, Encinas A, Keck J, Nising CF. Chemistry and Biology of Mycotoxins and Related Fungal Metabolites. Chem Rev 2009; 109:3903-90. [DOI: 10.1021/cr050001f] [Citation(s) in RCA: 411] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Stefan Bräse
- Institut für Organische Chemie,Karlsruhe Institute of Technology, Fritz-Haber-Weg 6, D-76131 Karlsruhe, Germany
| | - Arantxa Encinas
- Institut für Organische Chemie,Karlsruhe Institute of Technology, Fritz-Haber-Weg 6, D-76131 Karlsruhe, Germany
| | - Julia Keck
- Institut für Organische Chemie,Karlsruhe Institute of Technology, Fritz-Haber-Weg 6, D-76131 Karlsruhe, Germany
| | - Carl F. Nising
- Institut für Organische Chemie,Karlsruhe Institute of Technology, Fritz-Haber-Weg 6, D-76131 Karlsruhe, Germany
| |
Collapse
|
50
|
Elyashberg M, Blinov K, Williams A. A systematic approach for the generation and verification of structural hypotheses. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2009; 47:371-389. [PMID: 19197914 DOI: 10.1002/mrc.2397] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
During the process of molecular structure elucidation the selection of the most probable structural hypothesis may be based on chemical shift prediction. The prediction is carried out using either empirical or quantum-mechanical (QM) methods. When QM methods are used, NMR prediction commonly utilizes the GIAO option of the DFT approximation. In this approach the structural hypotheses are expected to be investigated by scientist. In this article we hope to show that the most rational manner by which to create structural hypotheses is actually by the application of an expert system capable of deducing all potential structures consistent with the experimental spectral data and specifically using 2D NMR data. When an expert system is used the best structure(s) can be distinguished using chemical shift prediction, which is best performed either by an incremental or neural net algorithm. The time-consuming QM calculations can then be applied, if necessary, to one or more of the 'best' structures to confirm the suggested solution.
Collapse
Affiliation(s)
- Mikhail Elyashberg
- Advanced Chemistry Development, Moscow Department, 6 Akademik Bakulev Street, Moscow 117513, Russian Federation
| | | | | |
Collapse
|