1
|
Winter J, Lühr S, Hochadel K, Gálvez-Vázquez MDJ, Prenzel T, Schollmeyer D, Waldvogel SR. Simple electrochemical synthesis of cyclic hydroxamic acids by reduction of nitroarenes. Chem Commun (Camb) 2024; 60:7065-7068. [PMID: 38904167 PMCID: PMC11223186 DOI: 10.1039/d4cc02118e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Accepted: 06/13/2024] [Indexed: 06/22/2024]
Abstract
The electrochemical reduction of nitroarenes allows direct access to manifold nitrogen containing heterocycles. This work reports the simple and direct electro-organic synthesis of 18 different examples of 2H,4H-4-hydroxy-1,4-benzoxazin-3-ones in up to 81% yield. The scalability of the method was demonstrated on a gram-scale.
Collapse
Affiliation(s)
- Johannes Winter
- Department of Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Susan Lühr
- Department of Chemistry, Faculty of Science, University of Chile, Las Palmeras 3425, Ñuñoa 775000, Santiago, Chile
| | - Kyra Hochadel
- Department of Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany
| | | | - Tobias Prenzel
- Department of Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Dieter Schollmeyer
- Department of Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Siegfried R Waldvogel
- Department of Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany
- Institute of Biological and Chemical Systems - Functional Molecular Systems (IBCS-FMS), Karlsruher Institut für Technologie (KIT), Kaiserstraße 12, 76131 Karlsruhe, Germany
- Max Planck Institute for Chemical Energy Conversion (MPI-CEC), Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany.
| |
Collapse
|
2
|
Hashmi SZ, Bareth D, Dwivedi J, Kishore D, Alvi PA. Green advancements towards the electrochemical synthesis of heterocycles. RSC Adv 2024; 14:18192-18246. [PMID: 38854834 PMCID: PMC11157331 DOI: 10.1039/d4ra02812k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Accepted: 05/22/2024] [Indexed: 06/11/2024] Open
Abstract
Heterocyclic chemistry is a large field with diverse applications in the areas of biological research and pharmaceutical advancement. Numerous initiatives have been proposed to further enhance the reaction conditions to reach these compounds without using harmful compounds. This paper focuses on the recent advances in the eco-friendly and green synthetic procedures to synthesize N-, S-, and O-heterocycles. This approach demonstrates considerable potential in accessing such compounds while circumventing the need for stoichiometric quantities of oxidizing/reducing agents or catalysts containing precious metals. Merely employing catalytic quantities of these substances proves sufficient, thereby offering an optimal means of contributing to resource efficiency. Renewable electricity plays a crucial role in generating environmentally friendly electrons (oxidant/reductant) that serve as catalysts for a series of reactions. These reactions involve the production of reactive intermediates, which in turn allow the synthesis of new chemical bonds, enabling beneficial transformations to occur. Furthermore, the utilization of metals as active catalysts in electrochemical activation has been recognized as an effective approach for achieving selective functionalization. The aim of this review was to summarize the electrochemical synthetic procedures so that the undesirable side reactions can be considerably reduced and the practical potential range of the chemical reactions can be expanded significantly.
Collapse
Affiliation(s)
- Sonia Zeba Hashmi
- Department of Chemistry, Banasthali Vidyapith Banasthali-304022 Rajasthan India
| | - Diksha Bareth
- Department of Chemistry, Banasthali Vidyapith Banasthali-304022 Rajasthan India
| | - Jaya Dwivedi
- Department of Chemistry, Banasthali Vidyapith Banasthali-304022 Rajasthan India
| | - Dharma Kishore
- Department of Chemistry, Banasthali Vidyapith Banasthali-304022 Rajasthan India
| | - P A Alvi
- Department of Physical Sciences, Banasthali Vidyapith Banasthali-304022 Rajasthan India
| |
Collapse
|
3
|
G Vishakantegowda A, Hwang D, Chakrasali P, Jung E, Lee JY, Shin JS, Jung YS. Highly potent and selective phosphatidylinositol 4-kinase IIIβ inhibitors as broad-spectrum anti-rhinoviral agents. RSC Med Chem 2024; 15:704-719. [PMID: 38389877 PMCID: PMC10880896 DOI: 10.1039/d3md00630a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Accepted: 12/08/2023] [Indexed: 02/24/2024] Open
Abstract
Human rhinoviruses (hRVs) cause upper and lower respiratory tract infections and exacerbate asthma and chronic obstructive pulmonary disease. hRVs comprise more than 160 strains with considerable genetic variation. Their high diversity and strain-specific interactions with antisera hinder the development of anti-hRV therapeutic agents. Phosphatidylinositol-4-kinase IIIβ (PI4KIIIβ) is a key enzyme in the phosphoinositide signalling pathway that is crucial for the replication and survival of various viruses. We identified novel PI4KIIIβ inhibitors, N-(4-methyl-5-arylthiazol)-2-amide derivatives, by generating a hit compound, 1a, from the high-throughput screening of a chemical library, followed by the optimization study of 1a. Inhibitor 7e exhibited the highest activity (EC50 = 0.008, 0.0068, and 0.0076 μM for hRV-B14, hRV-A16, and hRV-A21, respectively) and high toxicity (CC50 = 6.1 μM). Inhibitor 7f showed good activity and low toxicity and provided the highest selectivity index (SI ≥ 4638, >3116, and >2793 for hRV-B14, hRV-A16, and hRV-A21, respectively). Furthermore, 7f showed broad-spectrum activities against various hRVs, coxsackieviruses, and other enteroviruses, such as EV-A71 and EV-D68. The binding mode of the inhibitors was investigated using 7f, and the experimental results of plaque reduction, replicon and cytotoxicity, and time-of-drug-addition assays suggested that 7f acts as a PI4KIIIβ inhibitor. The kinase inhibition activity of this series of compounds against PI4KIIIα and PI4KIIIβ was assessed, and 7f demonstrated kinase inhibition activity with an IC50 value of 0.016 μM for PI4KIIIβ, but not for PI4KIIIα (>10 μM). Therefore, 7f represents a highly potent and selective PI4KIIIβ inhibitor for the further development of antiviral therapy against hRVs or other enteroviruses.
Collapse
Affiliation(s)
- Avinash G Vishakantegowda
- Infectious Diseases Therapeutic Research Center, Korea Research Institute of Chemical Technology Daejeon 34114 Republic of Korea
- Department of Medicinal Chemistry and Pharmacology, University of Science and Technology Daejeon 34113 Republic of Korea
| | - Dasom Hwang
- Infectious Diseases Therapeutic Research Center, Korea Research Institute of Chemical Technology Daejeon 34114 Republic of Korea
- Laboratory of Veterinary Virology, College of Veterinary Medicine, Chungbuk National University Cheongju 28644 Republic of Korea
| | - Prashant Chakrasali
- Infectious Diseases Therapeutic Research Center, Korea Research Institute of Chemical Technology Daejeon 34114 Republic of Korea
| | - Eunhye Jung
- Infectious Diseases Therapeutic Research Center, Korea Research Institute of Chemical Technology Daejeon 34114 Republic of Korea
| | - Joo-Youn Lee
- Infectious Diseases Therapeutic Research Center, Korea Research Institute of Chemical Technology Daejeon 34114 Republic of Korea
| | - Jin Soo Shin
- Infectious Diseases Therapeutic Research Center, Korea Research Institute of Chemical Technology Daejeon 34114 Republic of Korea
| | - Young-Sik Jung
- Infectious Diseases Therapeutic Research Center, Korea Research Institute of Chemical Technology Daejeon 34114 Republic of Korea
- Department of Medicinal Chemistry and Pharmacology, University of Science and Technology Daejeon 34113 Republic of Korea
| |
Collapse
|
4
|
Aslam S, Sbei N, Rani S, Saad M, Fatima A, Ahmed N. Heterocyclic Electrochemistry: Renewable Electricity in the Construction of Heterocycles. ACS OMEGA 2023; 8:6175-6217. [PMID: 36844606 PMCID: PMC9948259 DOI: 10.1021/acsomega.2c07378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Accepted: 01/20/2023] [Indexed: 06/18/2023]
Abstract
Numerous applications in the realm of biological exploration and drug synthesis can be found in heterocyclic chemistry, which is a vast subject. Many efforts have been developed to further improve the reaction conditions to access this interesting family to prevent employing hazardous ingredients. In this instance, it has been stated that green and environmentally friendly manufacturing methodologies have been introduced to create N-, S-, and O-heterocycles. It appears to be one of the most promising methods to access these types of compounds avoiding use of stoichiometric amounts of oxidizing/reducing species or precious metal catalysts, in which only catalytic amounts are sufficient, and it represent an ideal way of contributing toward the resource economy. Thus, renewable electricity provides clean electrons (oxidant/reductant) that initiate a reaction cascade via producing reactive intermediates that facilitate in building new bonds for valuable chemical transformations. Moreover, electrochemical activation using metals as catalytic mediators has been identified as a more efficient strategy toward selective functionalization. Thus, indirect electrolysis makes the potential range more practical, and less side reactions can occur. The latest developments in using an electrolytic strategy to create N-, S-, and O-heterocycles are the main topic of this mini review, which was documented over the last five years.
Collapse
Affiliation(s)
- Samina Aslam
- Department
of Chemistry, The Women University Multan, Multan60000, Pakistan
- The Department
of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, U.K.
| | - Najoua Sbei
- Institute
of Nanotechnology, Karlsruhe Institute of Technology, EggensteinLeopoldshafen, 76344KarlsruheGermany
| | - Sadia Rani
- Department
of Chemistry, The Women University Multan, Multan60000, Pakistan
| | - Manal Saad
- School
of Chemistry, Cardiff University, Main Building Park Place, Cardiff, CF10 3AT, United Kingdom
| | - Aroog Fatima
- Department
of Chemistry, The Women University Multan, Multan60000, Pakistan
| | - Nisar Ahmed
- School
of Chemistry, Cardiff University, Main Building Park Place, Cardiff, CF10 3AT, United Kingdom
| |
Collapse
|
5
|
Klein M, Waldvogel SR. Counter Electrode Reactions-Important Stumbling Blocks on the Way to a Working Electro-organic Synthesis. Angew Chem Int Ed Engl 2022; 61:e202204140. [PMID: 35668714 PMCID: PMC9828107 DOI: 10.1002/anie.202204140] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Indexed: 01/12/2023]
Abstract
Over the past two decades, electro-organic synthesis has gained significant interest, both in technical and academic research as well as in terms of applications. The omission of stoichiometric oxidizers or reducing agents enables a more sustainable route for redox reactions in organic chemistry. Even if it is well-known that every electrochemical oxidation is only viable with an associated reduction reaction and vice versa, the relevance of the counter reaction is often less addressed. In this Review, the importance of the corresponding counter reaction in electro-organic synthesis is highlighted and how it can affect the performance and selectivity of the electrolytic conversion. A selection of common strategies and unique concepts to tackle this issue are surveyed to provide a guide to select appropriate counter reactions for electro-organic synthesis.
Collapse
Affiliation(s)
- Martin Klein
- Department of ChemistryJohannes Gutenberg University MainzDuesbergweg 10–1455128MainzGermany
| | - Siegfried R. Waldvogel
- Department of ChemistryJohannes Gutenberg University MainzDuesbergweg 10–1455128MainzGermany
| |
Collapse
|
6
|
Lasky MR, Salvador TK, Mukhopadhyay S, Remy MS, Vaid TP, Sanford MS. Photochemical C(sp 2 )-H Pyridination via Arene-Pyridinium Electron Donor-Acceptor Complexes. Angew Chem Int Ed Engl 2022; 61:e202208741. [PMID: 36100577 PMCID: PMC9828204 DOI: 10.1002/anie.202208741] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Indexed: 01/12/2023]
Abstract
This report describes the development of a photochemical method for C(sp2 )-H pyridination that leverages the photoexcitation of electron donor-acceptor (EDA) complexes. Experimental and DFT studies show that black light (λmax ≈350 nm) irradiation of solutions of protonated pyridines (acceptors) and aromatic C-H substrates (donors) results in single electron transfer to form aryl radical cation intermediates that can be trapped with pyridine nucleophiles under aerobic conditions. With some modification of the reaction conditions, this EDA activation mode is also effective for promoting the oxidatively triggered SN Ar pyridination of aryl halides. Overall, this report represents an inexpensive and atom-economical approach to photochemical pyridination reactions that eliminates the requirement of an exogenous photocatalyst.
Collapse
Affiliation(s)
- Matthew R. Lasky
- Department of ChemistryUniversity of Michigan930 North University AvenueAnn ArborMichigan48109USA
| | - Tolani K. Salvador
- Department of ChemistryUniversity of Michigan930 North University AvenueAnn ArborMichigan48109USA
| | | | | | - Thomas P. Vaid
- Department of ChemistryUniversity of Michigan930 North University AvenueAnn ArborMichigan48109USA
| | - Melanie S. Sanford
- Department of ChemistryUniversity of Michigan930 North University AvenueAnn ArborMichigan48109USA
| |
Collapse
|
7
|
Berger M, Lenhard MS, Waldvogel SR. Para-Fluorination of Anilides Using Electrochemically Generated Hypervalent Iodoarenes. Chemistry 2022; 28:e202201029. [PMID: 35510825 PMCID: PMC9401020 DOI: 10.1002/chem.202201029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Indexed: 11/23/2022]
Abstract
The para-selective fluorination reaction of anilides using electrochemically generated hypervalent ArIF2 is reported, with Et3 N ⋅ 5HF serving as fluoride source and as supporting electrolyte. This electrochemical reaction is characterized by a simple set-up, easy scalability and affords a broad variety of fluorinated anilides from easily accessible anilides in good yields up to 86 %.
Collapse
Affiliation(s)
- Michael Berger
- Department of ChemistryJohannes Gutenberg University MainzDuesbergweg 10–1455128MainzGermany
| | - Marola S. Lenhard
- Department of ChemistryJohannes Gutenberg University MainzDuesbergweg 10–1455128MainzGermany
| | - Siegfried R. Waldvogel
- Department of ChemistryJohannes Gutenberg University MainzDuesbergweg 10–1455128MainzGermany
| |
Collapse
|
8
|
Liu S, Cheng X. Insertion of ammonia into alkenes to build aromatic N-heterocycles. Nat Commun 2022; 13:425. [PMID: 35058468 PMCID: PMC8776764 DOI: 10.1038/s41467-022-28099-w] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 01/05/2022] [Indexed: 12/30/2022] Open
Abstract
Ammonia is one of the most abundant and simple nitrogen sources with decent stability and reactivity. Direct insertion of ammonia into a carbon skeleton is an ideal approach to building valuable N-heterocycles for extensive applications with unprecedented atom and step economy. Here, we show an electrochemical dehydrogenative method in which ammonia is inserted directly into alkenes to build aromatic N-heterocycles in a single step without the use of any external oxidant. This new approach achieves 98–99.2% atom economy with hydrogen as the only byproduct. Quinoline and pyridine with diverse substitutions are readily available. In this work, electrochemistry was used to drive a 4-electron oxidation reaction that is hard to access by other protocols, providing a parallel pathway to nitrene chemistry. In a tandem transformation that included three distinct electrochemical processes, the insertion of ammonia further showcased the tremendous potential to manipulate heterocycles derived from Hantzsch ester to diazine via pyridine and pyrrole. Aromatic heterocycles containing nitrogen are ubiquitous in biologically relevant small molecules. Here the authors show an unorthodox methodology for their synthesis, by inserting the nitrogen atom into a carbon ring, with ammonia in electrochemical conditions.
Collapse
|
9
|
Buglioni L, Beslać M, Noël T. Dehydrogenative Azolation of Arenes in a Microflow Electrochemical Reactor. J Org Chem 2021; 86:16195-16203. [PMID: 34455793 PMCID: PMC8609577 DOI: 10.1021/acs.joc.1c01409] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
The electrochemical
synthesis of aryl azoles was performed for
the first time in a microflow reactor. The reaction relies on the
anodic oxidation of the arene partners making these substrates susceptible
for C–H functionalization with azoles, thus requiring no homogeneous
transition-metal-based catalysts. The synthetic protocol benefits
from the implementation of a microflow setup, leading to shorter residence
times (10 min), compared to previously reported batch systems. Various
azolated compounds (22 examples) are obtained in good to excellent
yields.
Collapse
Affiliation(s)
- Laura Buglioni
- Department of Chemical Engineering and Chemistry, Micro Flow Chemistry & Synthetic Methodology, Eindhoven University of Technology, Den Dolech 2, 5612 AZ Eindhoven, The Netherlands
| | - Marko Beslać
- Department of Chemical Engineering and Chemistry, Micro Flow Chemistry & Synthetic Methodology, Eindhoven University of Technology, Den Dolech 2, 5612 AZ Eindhoven, The Netherlands
| | - Timothy Noël
- Van't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park, 904 1098 XH Amsterdam, The Netherlands
| |
Collapse
|
10
|
Lugiņina J, Linden M, Bazulis M, Kumpiņš V, Mishnev A, Popov SA, Golubeva TS, Waldvogel SR, Shults EE, Turks M. Electrosynthesis of Stable Betulin‐Derived Nitrile Oxides and their Application in Synthesis of Cytostatic Lupane‐Type Triterpenoid‐Isoxazole Conjugates. European J Org Chem 2021. [DOI: 10.1002/ejoc.202100293] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Jevgeņija Lugiņina
- Faculty of Materials Science and Applied Chemistry RigaTechnical University P. Valdena Str.3 Riga 1007 Latvia
| | - Martin Linden
- Department of Chemistry Johannes Gutenberg University Mainz Duesbergweg 10–14 Mainz 55128 Germany
| | - Māris Bazulis
- Faculty of Materials Science and Applied Chemistry RigaTechnical University P. Valdena Str.3 Riga 1007 Latvia
| | - Viktors Kumpiņš
- Faculty of Materials Science and Applied Chemistry RigaTechnical University P. Valdena Str.3 Riga 1007 Latvia
| | - Anatoly Mishnev
- Latvian Institute of Organic Synthesis Aizkraukles Str. 21 Riga 1006 Latvia
| | - Sergey A. Popov
- Novosibirsk Institute of Organic Chemistry Academician Lavrentjev Ave. 9 Novosibirsk 630090 Russia
| | - Tatiana S. Golubeva
- The Federal Research Center Institute of Cytology and Genetics Acad. Lavrentyev Ave., 10 Novosibirsk 630090 Russia
| | - Siegfried R. Waldvogel
- Department of Chemistry Johannes Gutenberg University Mainz Duesbergweg 10–14 Mainz 55128 Germany
| | - Elvira E. Shults
- Novosibirsk Institute of Organic Chemistry Academician Lavrentjev Ave. 9 Novosibirsk 630090 Russia
| | - Māris Turks
- Faculty of Materials Science and Applied Chemistry RigaTechnical University P. Valdena Str.3 Riga 1007 Latvia
| |
Collapse
|
11
|
Wesenberg LJ, Diehl E, Zähringer TJB, Dörr C, Schollmeyer D, Shimizu A, Yoshida J, Hellmich UA, Waldvogel SR. Metal-Free Twofold Electrochemical C-H Amination of Activated Arenes: Application to Medicinally Relevant Precursor Synthesis. Chemistry 2020; 26:17574-17580. [PMID: 32866328 PMCID: PMC7839481 DOI: 10.1002/chem.202003852] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 08/28/2020] [Indexed: 01/13/2023]
Abstract
The efficient production of many medicinally or synthetically important starting materials suffers from wasteful or toxic precursors for the synthesis. In particular, the aromatic non-protected primary amine function represents a versatile synthetic precursor, but its synthesis typically requires toxic oxidizing agents and transition metal catalysts. The twofold electrochemical amination of activated benzene derivatives via Zincke intermediates provides an alternative sustainable strategy for the formation of new C-N bonds of high synthetic value. As a proof of concept, we use our approach to generate a benzoxazinone scaffold that gained attention as a starting structure against castrate-resistant prostate cancer. Further improvement of the structure led to significantly increased cancer cell line toxicity. Thus, exploiting environmentally benign electrooxidation, we present a new versatile and powerful method based on direct C-H activation that is applicable for example the production of medicinally relevant compounds.
Collapse
Affiliation(s)
- Lars J. Wesenberg
- Department of ChemistryJohannes Gutenberg University MainzDuesbergweg 10–1455128MainzGermany
| | - Erika Diehl
- Department of ChemistryJohannes Gutenberg University MainzJohann-Joachim Becherweg 3055128MainzGermany
- Center for Biomolecular Magnetic Resonance (BMRZ)Goethe-University FrankfurtMax-von-Laue Str. 960438Frankfurt/MGermany
| | - Till J. B. Zähringer
- Department of ChemistryJohannes Gutenberg University MainzDuesbergweg 10–1455128MainzGermany
| | - Carolin Dörr
- Department of ChemistryJohannes Gutenberg University MainzJohann-Joachim Becherweg 3055128MainzGermany
| | - Dieter Schollmeyer
- Department of ChemistryJohannes Gutenberg University MainzDuesbergweg 10–1455128MainzGermany
| | - Akihiro Shimizu
- Department Materials Engineering ScienceGraduate School of Engineering ScienceOsaka UniversityToyonakaOsaka 560–8531Japan
| | - Jun‐ichi Yoshida
- Department of ChemistryJohannes Gutenberg University MainzDuesbergweg 10–1455128MainzGermany
| | - Ute A. Hellmich
- Department of ChemistryJohannes Gutenberg University MainzJohann-Joachim Becherweg 3055128MainzGermany
- Center for Biomolecular Magnetic Resonance (BMRZ)Goethe-University FrankfurtMax-von-Laue Str. 960438Frankfurt/MGermany
| | - Siegfried R. Waldvogel
- Department of ChemistryJohannes Gutenberg University MainzDuesbergweg 10–1455128MainzGermany
| |
Collapse
|