1
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Janke S, Boldt S, Ghazargan K, Ehlers P, Villinger A, Langer P. Synthesis of Benzoacridines and Benzophenanthridines by Regioselective Pd-Catalyzed Cross-Coupling Reactions Followed by Acid-Mediated Cycloisomerizations. European J Org Chem 2019. [DOI: 10.1002/ejoc.201900913] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Sophie Janke
- Institute of Chemistry; University Rostock; Albert-Einstein-Str. 3a 18059 Rostock Germany
| | - Sebastian Boldt
- Institute of Chemistry; University Rostock; Albert-Einstein-Str. 3a 18059 Rostock Germany
| | - Karapet Ghazargan
- Institute of Chemistry; Yerevan State University; 1 Alek Manukyan St 0025 Yerevan Armenia
| | - Peter Ehlers
- Institute of Chemistry; University Rostock; Albert-Einstein-Str. 3a 18059 Rostock Germany
- Leibniz Institute for Catalysis at the University of Rostock e.V. (LIKAT); Albert-Einstein-Str. 29a 18059 Rostock Germany
| | - Alexander Villinger
- Institute of Chemistry; University Rostock; Albert-Einstein-Str. 3a 18059 Rostock Germany
| | - Peter Langer
- Institute of Chemistry; University Rostock; Albert-Einstein-Str. 3a 18059 Rostock Germany
- Leibniz Institute for Catalysis at the University of Rostock e.V. (LIKAT); Albert-Einstein-Str. 29a 18059 Rostock Germany
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2
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Bizzarri BM, Botta L, Capecchi E, Celestino I, Checconi P, Palamara AT, Nencioni L, Saladino R. Regioselective IBX-Mediated Synthesis of Coumarin Derivatives with Antioxidant and Anti-influenza Activities. JOURNAL OF NATURAL PRODUCTS 2017; 80:3247-3254. [PMID: 29236486 DOI: 10.1021/acs.jnatprod.7b00665] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Different catechol and pyrogallol derivatives have been synthesized by oxidation of coumarins with 2-iodoxybenzoic acid (IBX) in DMSO at 25 °C. A high regioselectivity was observed in accordance with the stability order of the incipient carbocation or radical benzylic-like intermediate. The oxidation was also effective in water under heterogeneous conditions by using IBX supported on polystyrene. The new derivatives showed improved antioxidant effects in the DPPH test and inhibitory activity against the influenza A/PR8/H1N1 virus. These data represent a new entry for highly oxidized coumarins showing an antiviral activity possibly based on the control of the intracellular redox value.
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Affiliation(s)
- Bruno M Bizzarri
- Department of Ecology and Biology, University of Tuscia , Via C. De Lellis, Viterbo, 01100, Italy
| | - Lorenzo Botta
- Department of Ecology and Biology, University of Tuscia , Via C. De Lellis, Viterbo, 01100, Italy
| | - Eliana Capecchi
- Department of Ecology and Biology, University of Tuscia , Via C. De Lellis, Viterbo, 01100, Italy
| | - Ignacio Celestino
- IRCCS, San Raffaele Pisana, Telematic University , Rome, 00163, Italy
| | - Paola Checconi
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti , Rome, 00161, Italy
| | - Anna T Palamara
- IRCCS, San Raffaele Pisana, Telematic University , Rome, 00163, Italy
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti , Rome, 00161, Italy
| | - Lucia Nencioni
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti , Rome, 00161, Italy
| | - Raffaele Saladino
- Department of Ecology and Biology, University of Tuscia , Via C. De Lellis, Viterbo, 01100, Italy
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3
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Szefler B, Diudea MV. Quantum-mechanical calculations on molecular substructures involved in nanosystems. Molecules 2014; 19:15468-506. [PMID: 25264833 PMCID: PMC6270685 DOI: 10.3390/molecules191015468] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 08/21/2014] [Accepted: 09/10/2014] [Indexed: 11/16/2022] Open
Abstract
In this review article, four ideas are discussed: (a) aromaticity of fullerenes patched with flowers of 6-and 8-membered rings, optimized at the HF and DFT levels of theory, in terms of HOMA and NICS criteria; (b) polybenzene networks, from construction to energetic and vibrational spectra computations; (c) quantum-mechanical calculations on the repeat units of various P-type crystal networks and (d) construction and stability evaluation, at DFTB level of theory, of some exotic allotropes of diamond D5, involved in hyper-graphenes. The overall conclusion was that several of the yet hypothetical molecular nanostructures herein described are serious candidates to the status of real molecules.
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Affiliation(s)
- Beata Szefler
- Department of Physical Chemistry, Collegium Medicum, Nicolaus Copernicus University, Kurpińskiego 5, Bydgoszcz 85-096, Poland
| | - Mircea V Diudea
- Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, Arany Janos street 11, Cluj-Napoca RO-400028, Romania.
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4
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Kethe A, Li A, Klumpp DA. Ring closing and opening reactions leading to aza-polycyclic aromatic compounds. Tetrahedron 2012; 68:3357-3360. [PMID: 24143035 DOI: 10.1016/j.tet.2012.02.047] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A series of functionalized aza-polycyclic aromatic compounds were prepared by a superacid-promoted ring closing and opening reaction cascade. A reaction mechanism is proposed, which involves reactive dicationic intermediates. A key step in the conversions involves ipso protonation of an aryl group and elimination of an alkyl phenyl group.
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Affiliation(s)
- Anila Kethe
- Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL 60115, United States
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5
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Borosky GL, Laali KK. In Silico study of carcinogenic o-Quinone metabolites derived from polycyclic aromatic hydrocarbons (PAHs). J PHYS ORG CHEM 2012. [DOI: 10.1002/poc.2924] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Gabriela L. Borosky
- Departamento de Matemática y Física, INFIQC, Facultad de Ciencias Químicas; Universidad Nacional de Córdoba; Ciudad Universitaria; Córdoba; 5000; Argentina
| | - Kenneth K. Laali
- Department of Chemistry; University of North Florida; 1, UNF Drive; Jacksonville; FL; 32224; USA
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6
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Borosky GL, Laali KK. Oxidized metabolites from cyclopenta-fused polycyclic aromatic hydrocarbons (CP-PAHs). A DFT model study of their carbocations formed by epoxide ring opening. J PHYS ORG CHEM 2010. [DOI: 10.1002/poc.1666] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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7
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Borosky GL, Laali KK. A DFT Model Study of the Carbocations Formed via the Fjord- and Bay-Region Diol Epoxide Metabolites of Isomeric Dibenzopyrenes and Naphthopyrene. European J Org Chem 2009. [DOI: 10.1002/ejoc.200900264] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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8
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Laali KK, Borosky GL. Stable carbocations and onium ions from polycondensed aromatic and heteroaromatic compounds as models for biological electrophiles and DNA-transalkylating agents. ADVANCES IN PHYSICAL ORGANIC CHEMISTRY 2009. [DOI: 10.1016/s0065-3160(08)00004-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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9
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Borosky GL. Carcinogenic carbocyclic and heterocyclic aromatic amines: A DFT study concerning their mutagenic potency. J Mol Graph Model 2008; 27:459-65. [DOI: 10.1016/j.jmgm.2008.08.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Revised: 08/06/2008] [Accepted: 08/09/2008] [Indexed: 11/15/2022]
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10
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Vijayalakshmi KP, Suresh CH. Theoretical studies on the carcinogenicity of polycyclic aromatic hydrocarbons. J Comput Chem 2008; 29:1808-17. [DOI: 10.1002/jcc.20939] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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11
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Vijayalakshmi KP, Suresh CH. Theoretical studies on the carcinogenic activity of diol epoxide derivatives of PAH: proton affinity and aromaticity as decisive descriptors. Org Biomol Chem 2008; 6:4384-90. [DOI: 10.1039/b813008f] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Laali KK, Chun JH, Okazaki T, Kumar S, Borosky GL, Swartz C. Electrophilic chemistry of thia-PAHs: stable carbocations (NMR and DFT), S-alkylated onium salts, model electrophilic substitutions (nitration and bromination), and mutagenicity assay. J Org Chem 2007; 72:8383-93. [PMID: 17910504 PMCID: PMC2532494 DOI: 10.1021/jo701502y] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
First examples of stable carbocations are reported from several classes of thia-PAHs with four fused rings, namely, benzo[b]naphtho[2,1-d]thiophene (1) and its 3-methoxy derivative (2), phenanthro[4,3-b]thiophene (3) and its 7-methoxy (4), 10-methoxy (5), and 9-methoxy (6) derivatives, phenanthro[3,4-b]thiophene (7) and its 7-methoxy (8) and 9-methoxy (9) derivatives, and 3-methoxybenzo[b]naphtha[1,2-d]thiophene (11). In several cases, the resulting carbocations were also studied by GIAO-DFT. Charge delocalization modes in the resulting carbocations were probed. A series of S-alkylated onium tetrafluoroborates, namely, 1Me+, 1Et+, 2Et+, and 7Me+ (from 1, 2, and 7), 10Me+ and 10Et+ (from benzo[b]naphtha[1,2-d]thiophene 10), 12Me+ and 12Et+ (from phenanthro[3,2-b][1]benzothiophene 12), 13Me+ (from 3-methoxyphenanthro[3,2-b]benzothiophene 13), 14Me+ (from phenanthro[4,3-b][1]benzothiophene 14), and 15Me+ (from 3-methoxyphenanthro[4,3-b][1]benzothiophene 15), were synthesized. PAH-sulfonium salts 1Me+, 1Et+, 10Me+, 10Et+, 12Me+, and 14Me+ proved to be efficient akylating agents toward model nitrogen nucleophile receptors (imidazole and azaindole). Facile transalkylation to model nucleophiles (including guanine) is also supported by favorable reaction energies computed by DFT. Ring opening energies in thia-PAH-epoxides from 1, 3, and 7 and charge delocalization modes in the resulting carbocations were also evaluated. The four-ring-fused thia-PAHs 1, 2, 3, 4, 5, 7, 8, and 11 are effectively nitrated under extremely mild conditions. Nitration regioselectivity corresponds closely to protonation under stable ion conditions. Bromination of 4 and 6 is also reported. Comparative mutagenicity assays (Ames test) were performed on 1 versus 1NO2, 5 versus 5NO2, and 11 versus 11NO2. Compound 5NO2 was found to be a potent direct acting mutagen.
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Affiliation(s)
- Kenneth K Laali
- Department of Chemistry, Kent State University, Kent, Ohio 44242, USA.
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Borosky GL. Ultimate Carcinogenic Metabolites from Aromatic and Heterocyclic Aromatic Amines: A Computational Study in Relation to Their Mutagenic Potency. Chem Res Toxicol 2007; 20:171-80. [PMID: 17261035 DOI: 10.1021/tx600278q] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The formation of nitrenium ions from their precursors was examined by density functional theory (DFT) calculations in order to analyze the role of these electrophilic intermediates on the mutagenic activity of the parent amines. The relative reactivities for N-O bond dissociation from the N-hydroxy, N-acetoxy and N-sulfate derivatives of aniline were evaluated. Furthermore, the N-acetoxy esters from a set of 17 aromatic and heteroaromatic amines of diverse structure were considered, and correlations were sought between the calculated properties and the reported mutagenic potencies. The mutagenic activity was found to increase when a more negative charge developed at the exocyclic nitrogen of the nitrenium ion (qN) and with nitrenium ion stability. Different functional correlations were observed for the amine derivatives grouped according to their classification as aromatic (Ar), imidazo-carbocyclic (Imi-C), and imidazo-heterocyclic (Imi-H). The formation of N-acetyl nitrenium ions from aromatic amides was also considered and found to be less favorable than nitrenium ion generation from the corresponding amines.
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Affiliation(s)
- Gabriela L Borosky
- Unidad de MatemAtica y Física, INFIQC, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba 5000, Argentina.
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14
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Borosky GL, Laali KK. Oxidized metabolites from benzo[a]pyrene, benzo[e]pyrene, and aza-benzo[a]pyrenes. A computational study of their carbocations formed by epoxide ring opening reactions. Org Biomol Chem 2007; 5:2234-42. [PMID: 17609754 DOI: 10.1039/b704090c] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A DFT study aimed at understanding structure-reactivity relationships and fluorine substitution effects on carbocation stability in benzo[a]pyrene (BaP), benzo[e]pyrene (BeP), and aza-benzo[a]pyrene (aza-BaP) derivatives are reported. The relative energies of the resulting carbocations are examined and compared, taking into account the available biological activity data on these compounds. O-Protonation of the epoxides and diol epoxides leads to carbocation formation by barrierless processes. Charge delocalization modes in the resulting carbocations were deduced via NPA-derived changes in charges, and fluorine substitution effects were analyzed on the basis of charge density at different carbocation positions. Thus, fluorine substitution at sites bearing negative charge generated inductive destabilization of the carbocation, whereas a fluorine atom at a ring position which presented significant positive charge density produced a less pronounced destabilization due to fluorine p-pi back-bonding. Protonation reactions were also studied for the azaBaPs. In selected cases, the covalent adducts generated via bond formation with the exocyclic nitrogen of cytosine were computed and relative energies and geometries of the resulting adducts were examined.
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Affiliation(s)
- Gabriela L Borosky
- Unidad de Matemática y Física, INFIQC, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba, 5000, Argentina.
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15
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Borosky GL, Laali KK. Carbocations from oxidized metabolites of benzo[a]anthracene: a computational study of their methylated and fluorinated derivatives and guanine adducts. Chem Res Toxicol 2006; 19:899-907. [PMID: 16841957 PMCID: PMC2538532 DOI: 10.1021/tx060067l] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Structure-reactivity relationships and substituent effects on carbocation stability in benzo[a]anthracene (BA) derivatives have been studied computationally at the B3LYP/6-31G and MP2/6-31G levels. Bay-region carbocations are formed by O-protonation of the 1,2-epoxides in barrierless processes. This process is energetically more favored as compared to carbocation generation via zwitterion formation/O-protonation, via single electron oxidation to generate a radical cation, or via benzylic hydroxylation. Relative carbocation stabilities were determined in the gas phase and in water as solvent (PCM method). Charge delocalization mode in the BA carbocation framework was deduced from NPA-derived changes in charges, and substitution by methyl or fluorine was studied at different positions selected on basis of the carbocation charge density. A bay-region methyl group produces structural distortion with consequent deviation from planarity of the aromatic system, which destabilizes the epoxide, favoring ring opening. Whereas fluorine substitution at sites bearing significant positive charge leads to carbocation stabilization by fluorine p-pi back-bonding, a fluorine atom at a ring position which presented negative charge density leads to inductive destabilization. Methylated derivatives are less sensitive to substituent effects as compared to the fluorinated analogues. Although the solvent decreases the exothermicity of the epoxide ring-opening reactions due to greater stabilization of the reactants, it provokes no changes in relative reactivities. Relative energies in the resulting bay-region carbocations are examined taking into account the available biological activity data on these compounds. In selected cases, quenching of bay-region carbocations was investigated by analyzing relative energies (in the gas phase and in water) and geometries of their guanine adducts formed via covalent bond formation with the exocyclic amino group and with the N-7.
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Affiliation(s)
- Gabriela L. Borosky
- Unidad de Matemática y Física, INFIQC, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba 5000, Argentina
| | - Kenneth K. Laali
- Department of Chemistry, Kent State University, Kent, Ohio 44242, USA
- * To whom correspondence should be addressed. Tel: 330-6722988. Fax: 330-6723816. E-mail:
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Li A, Kindelin PJ, Klumpp DA. Charge Migration in Dicationic Electrophiles and Its Application to the Synthesis of Aza-polycyclic Aromatic Compounds. Org Lett 2006; 8:1233-6. [PMID: 16524311 DOI: 10.1021/ol060125u] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] Superacid-promoted reactions of dicationic electrophiles have been studied, and the positive charge centers are found to migrate apart in a predictable manner. Using isotopic labeling the charge migration is found in one system to occur through successive deprotonation-reprotonation steps. The charge migration chemistry is the basis for new general synthetic route to aza-polycyclic aromatic compounds.
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Affiliation(s)
- Ang Li
- Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois 60115, USA
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17
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Borosky GL, Laali KK. A Computational Study of Carbocations from Oxidized Metabolites of Dibenzo[a,h]acridine and Their Fluorinated and Methylated Derivatives. Chem Res Toxicol 2005; 18:1876-86. [PMID: 16359178 DOI: 10.1021/tx0501841] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In a model computational study aimed at understanding structure-reactivity relationships and substituent effects on carbocation stability in aza-polycyclic aromatic hydrocarbons, the epoxides, diol epoxides, and the dihydrodiols of dibenzo[a,h]acridine (DB[a,h]ACR) were studied by density functional theory at the B3LYP/6-31G level. Bay region carbocations were formed via the O-protonated epoxides in barrierless processes. Relative carbocation stabilities were determined in the gas phase and in water as solvent (polarized continuum model method). Charge delocalization modes in the resulting carbocations were deduced by gauge-independent atomic orbitals (GIAO) NMR (based on Delta delta13C values) and via the natural population analysis (NPA)-derived changes in charges. Although the solvent decreases the exothermicity of the epoxide ring-opening reactions due to greater stabilization of the reactants, relative reactivity trends remain the same. Whereas fluorine substitution at ring positions bearing significant positive charge leads to carbocation stabilization by fluorine p-pi back-bonding, fluorine substitution at a ring position that presented negative charge density in the unsubstituted compound leads to inductive destabilization. Methylated derivatives exhibit less sensitivity to substituent effects as compared to the fluorinated analogues. A bay region methyl group produces structural distortion, and this deviation from planarity destabilizes the epoxide, favoring ring opening. Relative energies, changes in NPA charges, and GIAO NMR data in the resulting "benzylic" carbocations are examined collectively and discussed, taking into account the available biological activity data on these compounds.
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Affiliation(s)
- Gabriela L Borosky
- Unidad de Matemática y Física, INFIQC, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba 5000, Argentina
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