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Anders L, Lindel T. Azido and desamino analogs of the marine natural product oroidin. ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES 2023. [DOI: 10.1515/znb-2023-0305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Abstract
As part of our program on the synthesis and reactivity of the pyrrole-imidazole alkaloids from marine sponges, the synthesis of the 2-azido analog of the key marine natural product oroidin is reported. In addition, desaminooroidin and its alkyne analog were synthesized. Red-Al reduction of a 4-alkynylimidazole intermediate afforded the (E)-alkene, without having to pass via the (Z)-alkene. Coupling of 4,5-dibromopyrrole-2-carboxylic acid with 2-azidoimidazolylprop-2-en-1-amine was best achieved by EDCI-mediated coupling, which was superior to using the corresponding trichloromethylketone. Use of t-BuOK in acetonitrile can be recommended for the coupling of non-azidated alkenyl and alkynylimidazoles. The azido analog of oroidin underwent click cycloadditions to imidazolyltriazoles.
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Affiliation(s)
- Lisa Anders
- TU Braunschweig, Institute of Organic Chemistry , Hagenring 30, 38106 Braunschweig , Germany
| | - Thomas Lindel
- TU Braunschweig, Institute of Organic Chemistry , Hagenring 30, 38106 Braunschweig , Germany
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Kanitz NE, Fresia M, Jones PG, Lindel T. Di‐ and Trifluorinated 2‐Azidobenzimidazole Derivatives: Synthesis, Photooxygenation, and
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F NMR Prediction. European J Org Chem 2021. [DOI: 10.1002/ejoc.202100603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Nils E. Kanitz
- Institute of Organic Chemistry Technical University Braunschweig Hagenring 30 38106 Braunschweig Germany
| | - Marvin Fresia
- Institute of Organic Chemistry Technical University Braunschweig Hagenring 30 38106 Braunschweig Germany
| | - Peter G. Jones
- Institute of Inorganic and Analytical Chemistry Technical University Braunschweig Hagenring 30 38106 Braunschweig Germany
| | - Thomas Lindel
- Institute of Organic Chemistry Technical University Braunschweig Hagenring 30 38106 Braunschweig Germany
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Nilov DI, Komarov DY, Panov MS, Karabaeva KE, Mereshchenko AS, Tarnovsky AN, Wilson RM. Oxidation of adenosine and inosine: the chemistry of 8-oxo-7,8-dihydropurines, purine iminoquinones, and purine quinones as observed by ultrafast spectroscopy. J Am Chem Soc 2013; 135:3423-38. [PMID: 23339714 DOI: 10.1021/ja3068148] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Oxidative damage to purine nucleic acid bases proceeds through quinoidal intermediates derived from their corresponding 8-oxo-7,8-dihydropurine bases. Oxidation studies of 8-oxo-7,8-dihyroadenosine and 8-oxo-7,8-dihydroinosine indicate that these quinoidal species can produce stable cross-links with a wide variety of nucleophiles in the 2-positions of the purines. An azide precursor for the adenosine iminoquinone has been synthesized and applied in ultrafast transient absorption spectroscopic studies. Thus, the adenosine iminoquinone can be observed directly, and its susceptibility to nucleophilic attack with various nucleophiles as well as the stability of the resulting cross-linked species have been evaluated. Finally, these observations indicate that this azide might be a very useful photoaffinity labeling agent, because the reactive intermediate, adenosine iminoquinone, is such a good mimic for the universal purine base adenosine.
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Affiliation(s)
- Denis I Nilov
- Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States
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Sudakow A, Jones PG, Lindel T. Photochemical Arylation of Brønsted Acids with 2-Azidobenzimidazole. European J Org Chem 2011. [DOI: 10.1002/ejoc.201101711] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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D'Auria M, Racioppi R, Viggiani L, Zanirato P. Photochemical Reactivity of 2-Azido-1,3-thiazole and 2-Azido-1,3-benzothiazole: A Procedure for the Aziridination of Enol Ethers. European J Org Chem 2009. [DOI: 10.1002/ejoc.200800959] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Polshakov D, Rai S, Wilson RM, Mack ET, Vogel M, Krause JA, Burdzinski G, Platz MS. Photoaffinity labeling with 8-azidoadenosine and its derivatives: chemistry of closed and opened adenosine diazaquinodimethanes. Biochemistry 2005; 44:11241-53. [PMID: 16101308 DOI: 10.1021/bi050859z] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reactive intermediate produced upon photolysis of 8-azidoadenosine was studied by chemical trapping studies, laser flash photolysis with UV-vis and IR detection, and modern computational chemistry. It is concluded that photolysis of 8-azidoadenosine in aqueous solution releases the corresponding singlet nitrene which rapidly tautomerizes to form a closed adenosine diazaquinodimethane in less than 400 fs. A perbenzoylated derivative of 8-azidoadenosine cannot undergo this tautomerization, and instead, it fragments upon photolysis to form an opened adenosine diazaquinodimethane. The singlet nitrene is too short-lived to be observed and, thus, to relax to the lowest triplet state or to become covalently attached to targeted biological macromolecules. The pivotal closed adenosine diazaquinodimethane, the product of nitrene tautomerization, has a lifetime of ca. 1 min or longer in water and in HEPES buffer at ambient temperature. However, this intermediate reacts rapidly with good nucleophiles such as amines, thiols, and phenolates, and significantly more slowly with weak nucleophiles such as alcohols and water. On the basis of these studies, it is clear that the closed adenosine diazaquinodimethane, and not the singlet or triplet nitrene, is the pivotal reactive intermediate involved in photolabeling and cross-linking studies using the 8-azidoadenosine family of photoaffinity labeling reagents.
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Affiliation(s)
- Dmitrii Polshakov
- Department of Chemistry, The Ohio State University, Columbus, Ohio 43210, USA
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Zanirato P, Cerini S. On the utility of the azido transfer protocol: synthesis of 2- and 5-azido N-methylimidazoles, 1,3-thiazoles and N-methylpyrazole and their conversion to triazole–azole bisheteroaryls. Org Biomol Chem 2005; 3:1508-13. [PMID: 15827649 DOI: 10.1039/b500634a] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The azido transfer procedure of heteroaryllithium and tosyl azide was used to synthesize selected 2- and 5-azidoazoles. This procedure, which is based on the fragmentation of the appropriate lithium triazene salts 1a-7a, successfully afforded 2-azido-N-methylimidazole 1, 2-azido-1,3-thiazole 2, 2-azidobenzo-1,3-thiazole 3, 5-azido-N-methylpyrazole 4, 5-azido-N-methylimidazole 6[via 2-(trimethylsilyl)-5-azido-N-methylimidazole 5], and 5-azido-1,3-thiazole 7 (via 5-lithio-1,3-thiazole), but attempts to prepare 5-azido-2-(trimethylsilyl)-1,3-thiazole 8 from the corresponding triazene 7a failed, affording only the desilylated azide in poor yield. Azides - underwent 1,3-dipolar cycloaddition when mixed with neat (trimethylsilyl)acetylene, giving 1-heteroaryl-4-trimethylsilyl-1,2,3-triazoles 1b-7b generally in very high yields.
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Affiliation(s)
- Paolo Zanirato
- Dip.to di Chimica Organica A. Mangini, Università degli Studi di Bologna, Italy.
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Facchini P, Grandinetti F. Concerning the reaction between singlet nitrenium ions and water: a computational investigation on competitive reaction paths. J Comput Chem 2003; 24:547-64. [PMID: 12632470 DOI: 10.1002/jcc.10182] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The reaction between singlet nitrenium ions XNH(+) (X = F and Cl) and H(2)O has been investigated by high-level of theory ab initio calculations. The geometries of the involved intermediates, transition structures, and dissociation products have been optimized at the MP2(full)/6-31G(d) level of theory, and accurate total energies have been obtained using the Gaussian-3 (G3) procedure. The reaction commences by the exothermic formation of the F-NH-OH(2) (+) and Cl-NH-OH(2) (+) intermediates, which are in turn able to undergo two distinct low-energy reaction paths, namely, the isomerization to the N-protonated isomers of the hydroxylamines F-NH-OH or Cl-NH-OH, and the eventual extrusion of HF or HCl. The competitive or alternative occurrence of these two processes strictly depends on the nature of the substituent X. In the reaction between FNH(+) and H(2)O, the energy gained in the formation of the complex F-NH-OH(2) (+) from the association between FNH(+) and H(2)O, 52.1 kcal mol(-1), is by far larger than the activation barrier for the loss of HF from F-NH-OH(2) (+), computed as 24.9 kcal mol(-1). In addition, the F-NH-OH(2) (+) intermediate requires 33.0 kcal mol(-1) to overcome the barrier for the isomerization to F-NH(2)-OH(+). Therefore, the reaction between FNH(+) and H(2)O is expected to occur practically exclusively by HF elimination with formation of the HN-OH(+) ionic product. On the other hand, for the reaction between ClNH(+) and H(2)O, it is not possible to get a definitive conclusion on the competitive or alternative occurrence of the two reaction paths. In fact, the transition structure involved in the elimination of HCl from Cl-NH-OH(2) (+) is only 3.4 kcal mol(-1) lower in energy than the transition structure for the isomerization of Cl-NH-OH(2) (+) to Cl-NH(2)-OH(+). In addition, the absolute values of the energy barriers of these two processes, 24.2 and 27.6 kcal mol(-1), respectively, are comparable with the energy gained in the formation of the complex Cl-NH-OH(2) (+) from the association between ClNH(+) and H(2)O, 24.0 kcal mol(-).1 Therefore, the ClNH(+) cation is predicted to react with water significantly slower than FNH(+).
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Affiliation(s)
- Paola Facchini
- Dipartimento di Scienze Ambientali and Istituto Nazionale di Fisica della Materia (INFM), Unità di Viterbo, Università della Tuscia, Largo dell' Università, 01100, Viterbo, Italy
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Ruane PH, McClelland RA. Kinetic stabilizing effect of the 4-N-methylacetamido substituent on the phenylnitrenium ion. CAN J CHEM 2001. [DOI: 10.1139/v01-178] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Photolysis of 4-(N-methylacetamido)phenyl azide in aqueous solution results in quantitative formation of the 4-(N-methylacetamido)phenylnitrenium ion, this cation arising from solvent protonation of an initially formed singlet arylnitrene. The cation is observed by flash photolysis, and is identified through characteristic quenching by azide ion and by 2'-deoxyguanosine, both excellent nucleophiles for arylnitrenium ions in water. The nitrenium ion is protonated in acidic solutions to form the 4-(N-methylacetamido)aniline dication, whose pKa is determined to be 1.5 based on the ratepH profile. This means that the nitrenium ion is relatively basic, which suggests that there is significant positive charge on the N-methylacetamido group. Further evidence for this is seen in the remarkably long lifetime (5 ms) of the nitrenium ion in water. In fact, the 4-(N-methylacetamido)phenylnitrenium ion is 5000-fold longer-lived than the 4-methoxy-substituted analog. A 4-methoxy substituent on a phenyl ring is more electron donating according to σ+ values (0.78 for MeO vs. 0.60 for NMeAc). The dramatic reversal in the arylnitrenium ions is another example of the failure of these to follow the carbocation scale.Key words: nitrenium ion, flash photolysis, amide substituent.
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N-arylnitreniurn ions. ADVANCES IN PHYSICAL ORGANIC CHEMISTRY 2001. [DOI: 10.1016/s0065-3160(01)36005-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
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McClelland RA, Ren D, D'Sa R, Ahmed AR. Acidity constants and reactivities of the benzidine and N, N-dimethylbenzidine dications, the two electron oxidation intermediates of benzidine carcinogens. CAN J CHEM 2000. [DOI: 10.1139/v00-123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This paper describes the behavior in aqueous solutions of the two electron oxidation products of the carcinogens benzidine and N,N-dimethylbenzidine. In biological systems there is evidence that these diamines are oxidized by peroxidases, and that a product of this oxidation may be partly responsible for carcinogenicity. Entry into the oxidation products in the present study was provided through the bis-perchlorate salts of dications obtained upon chemical oxidation and through the irradiation of 4'-amino and 4'-N,N-dimethylamino-4-azidobiphenyls. The benzidine oxidation product exists in three conjugate acid-base forms, a dication, a monocation and neutral bisimine, with pKa(1) = 5.0 and pKa(2) = 9.0. These values stand in marked contrast to ones previously obtained for the two electron oxidation product of p-phenylenediamine, pKa(1) < 1.5 and pKa(2) = 5.75. The dimethylamino derivative, blocked from forming the neutral form, exists as a dication and monocation, with pKa= 5.0. Both systems are quite long-lived in aqueous solution, but they do decay on the minutes-to-hours time scale. The kinetics can be explained by reactions of both the dication and the monocation with water, with a reaction of hydroxide and the monocation becoming important around pH 10. One surprising result is that the monocations are two orders of magnitude more reactive than the dications. Thus, at neutral pH the form that exists in both systems is the monocation, and this is the species that is the most reactive towards the solvent. One of the resonance contributors in the monocation is a 4-biphenylylnitrenium ion. Comparison with other 4'-substituted-4-biphenylylnitrenium ions studied by laser flash photolysis shows that the 4'-amino- and 4'-dimethylamino substituents are highly kinetically stabilizing. These cations, for example, are a billion-fold longer-lived in aqueous solution than the parent 4-biphenylylnitrenium ion.Key words: quinone bisimine, nitrenium, aryl azide.
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Sullivan MB, Cramer CJ. Quantum Chemical Analysis of Heteroarylnitrenium Ions and Mechanisms for Their Self-Destruction. J Am Chem Soc 2000. [DOI: 10.1021/ja0005486] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Michael B. Sullivan
- Contribution from the Department of Chemistry and Supercomputer Institute, University of Minnesota, 207 Pleasant St. SE, Minneapolis, Minnesota 55455-0431
| | - Christopher J. Cramer
- Contribution from the Department of Chemistry and Supercomputer Institute, University of Minnesota, 207 Pleasant St. SE, Minneapolis, Minnesota 55455-0431
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