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Hong D, Falvey DE. Rearrangement, Elimination, and Ring-Opening Reactions of Cyclopropyl-Substituted Nitrenium Ions: A Computational and Experimental Investigation. J Org Chem 2024; 89:10785-10795. [PMID: 39004832 DOI: 10.1021/acs.joc.4c01014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
N-(4-Biphenylyl)-N-cyclopropyl nitrenium ion 5 and N-benzyl-N-cyclopropyl nitrenium ion (6) were generated through photolysis of their corresponding N-aminopyridinium ion photoprecursors. In the case of 5, stable products result from a combination of cyclopropyl ring expansion (N-biphenylazetium ion) and ethylene elimination (biphenylisonitrilium ion). When present in high concentrations, methanol can add to the cyclopropyl ring-forming N-3-methoxypropyl-N-biphenyl iminium ion. In contrast, the only detectable product from the N-benzyl-N-cyclopropyl nitrenium ion (6) is benzylisonitrile, resulting from the elimination of ethylene. Density functional theory (DFT) calculations predict the product distributions from the more stable biphenyl system 5 with reasonable accuracy. However, product distributions from the less stable benzyl system 6 are forecast with less accuracy.
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Affiliation(s)
- Donald Hong
- Department of Chemistry and Biochemistry University of Maryland College Park, Maryland 20742, United States
| | - Daniel E Falvey
- Department of Chemistry and Biochemistry University of Maryland College Park, Maryland 20742, United States
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2
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Photochemical generation and characterization of the 5-endo-10,11-dihydrodibenzoazepine nitrenium ion. Photochem Photobiol Sci 2022; 21:1907-1914. [DOI: 10.1007/s43630-022-00267-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Accepted: 07/04/2022] [Indexed: 10/17/2022]
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3
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Kütt A, Jeschke G, Toom L, Nerut J, Reed CA. Reactivity of Diarylnitrenium Ions. Chemistry 2020; 26:8871-8874. [PMID: 32180268 DOI: 10.1002/chem.202000930] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 03/13/2020] [Indexed: 01/29/2023]
Abstract
Hydride abstraction from diarylamines with the trityl ion is explored in an attempt to generate a stable diarylnitrenium ion, Ar2 N+ . Sequential H-atom abstraction reactions ensue. The first H-atom abstraction leads to intensely colored aminium radical cations, Ar2 NH.+ , some of which are quite stable. However, most undergo a second H-atom abstraction leading to ammonium ions, Ar2 NH2 + . In the absence of a ready source of H-atoms, a unique self-abstraction reaction occurs when Ar=Me5 C6 , leading to a novel iminium radical cation, Ar=N.+ Ar, which decays via a second self H-atom abstraction reaction to give a stable iminium ion, Ar=N+ HAr. These products differ substantially from those derived via photochemically produced diarylnitrenium ions.
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Affiliation(s)
- Agnes Kütt
- Institute of Chemistry, University of Tartu, Ravila 14A, 50411, Tartu, Estonia.,Department of Chemistry, University of California, Riverside, CA, 92521, USA
| | - Gunnar Jeschke
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093, Zurich, Switzerland
| | - Lauri Toom
- Institute of Chemistry, University of Tartu, Ravila 14A, 50411, Tartu, Estonia
| | - Jaak Nerut
- Institute of Chemistry, University of Tartu, Ravila 14A, 50411, Tartu, Estonia
| | - Christopher A Reed
- Department of Chemistry, University of California, Riverside, CA, 92521, USA
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4
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Zeppuhar AN, Falvey DE. Generation of N, N-Di(4-bromophenyl)nitrenium Ion under Acidic Conditions: Search for a Nitrenium Dication. J Org Chem 2020; 85:8844-8850. [PMID: 32589031 DOI: 10.1021/acs.joc.0c00686] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The behavior of the N,N-di(4-bromophenyl)nitrenium ion under acidic aqueous conditions was examined via laser flash photolysis experiments. A long-lived species forms and can be assigned as the cation radical or the dication. This species is unreactive toward nucleophiles and reactive toward strong electron donors, consistent with a cation radical. Mechanistic analysis indicates that its formation is through a separate pathway compared to that of the nitrenium ion, suggestive of a triplet mechanism.
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Affiliation(s)
- Andrea N Zeppuhar
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742 United States
| | - Daniel E Falvey
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742 United States
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5
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Du L, Yan Z, Zhu Z, Cheng SC, Zhang Y, Li X, Tang W, Phillips DL. Time-Resolved Spectroscopic Observation of Diphenylnitrenium Ion Reactions with Guanosine. J Org Chem 2020; 85:8792-8797. [PMID: 32527081 DOI: 10.1021/acs.joc.0c00517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Arylnitrenium ions have gained attention for their high reactivity toward guanosine, which in some cases has been linked to carcinogenesis. Although many studies have examined covalent addition reactions between arylnitrenium ions and guanosine, there is still some uncertainty regarding the attack position of nitrenium ions on guanosine and its derivatives. In this paper, we employ nanosecond transient absorption and nanosecond time-resolved resonance Raman spectroscopy to investigate the reaction between the N,N-di(4-bromophenyl) nitrenium ion (2) and guanosine. Our time-resolved spectroscopic results and photochemical product analysis results show that the reaction of guanosine with 2 generates an N7 intermediate that subsequently undergoes rearrangement and deprotonation to produce a C8 adduct. Comparing these results to our previous study between the 2-fluorenylnitrenium ion and guanosine indicates that the structure and properties of arylnitrenium ions are able to influence the reaction pathways and intermediate structures.
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Affiliation(s)
- Lili Du
- Department of Chemistry, The University of Hong Kong, Hong Kong S.A.R., P. R. China.,School of Life Sciences, Jiangsu University, Zhenjiang 212013, P. R. China
| | - Zhiping Yan
- Department of Chemistry, The University of Hong Kong, Hong Kong S.A.R., P. R. China.,Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing 211816, P. R. China
| | - Zhiyuan Zhu
- Department of Chemistry, The University of Hong Kong, Hong Kong S.A.R., P. R. China
| | - Shun-Cheung Cheng
- Department of Chemistry, The University of Hong Kong, Hong Kong S.A.R., P. R. China
| | - Yue Zhang
- Department of Chemistry, The University of Hong Kong, Hong Kong S.A.R., P. R. China
| | - Xuechen Li
- Department of Chemistry, The University of Hong Kong, Hong Kong S.A.R., P. R. China
| | - Wenjian Tang
- School of Pharmacy, Anhui Medical University, Meishan Road 81, Hefei 230032, P. R. China
| | - David Lee Phillips
- Department of Chemistry, The University of Hong Kong, Hong Kong S.A.R., P. R. China
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6
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Time-Resolved Spectroscopic Study of N,N-Di(4-bromo)nitrenium Ions in Acidic Aqueous Solution. Int J Mol Sci 2019; 20:ijms20215512. [PMID: 31694248 PMCID: PMC6862224 DOI: 10.3390/ijms20215512] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 10/28/2019] [Accepted: 10/31/2019] [Indexed: 12/03/2022] Open
Abstract
Nitrenium ions are common reactive intermediates with high activities towards some biological nucleophiles. In this paper, we employed femtosecond transient absorption (fs-TA) and nanosecond transient absorption (ns-TA) as well as nanosecond time-resolved resonance Raman (ns-TR3) spectroscopy and density function theory (DFT) calculations to study the spectroscopic properties of the N(4,4′–dibromodiphenylamino)–2,4,6–trimethylpyridinium BF4− salt (1) in an acidic aqueous solution. Efficient cleavage of the N–N bond (4 ps) to form the N,N–di(4–bromophenyl)nitrenium ion (DN) was also observed in the acidic aqueous solution. As a result, the dication intermediate 4 appears more likely to be produced after abstracting a proton for the nitrenium ion DN in the acid solution first, followed by an electron abstraction to form the radical cation intermediate 3. These new and more extensive time-resolved spectroscopic data will be useful to help to develop an improved understanding of the identity, nature, and properties of nitrenium ions involved in reactions under acidic aqueous conditions.
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Abstract
Herein, we report a C-N coupling reaction via antiaromatic endocyclic nitrenium ions. The nitrenium ion intermediate was generated by a combination of iodine(III) reagent PhI(OCOCF3)2 and the N-H center of benzimidazole units at ambient laboratory conditions. Metal-free synthesis of benzimidazole-fused phenanthridine derivatives was achieved in good to excellent yields.
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Affiliation(s)
- Shyamal Kanti Bera
- School of Chemical Sciences , National Institute of Science Education and Research (NISER), HBNI , PO Bhimpur-Padanpur, Via Jatni , District Khurda, Bhubaneswar , Odisha 752050 , India
| | - Md Toufique Alam
- School of Chemical Sciences , National Institute of Science Education and Research (NISER), HBNI , PO Bhimpur-Padanpur, Via Jatni , District Khurda, Bhubaneswar , Odisha 752050 , India
| | - Prasenjit Mal
- School of Chemical Sciences , National Institute of Science Education and Research (NISER), HBNI , PO Bhimpur-Padanpur, Via Jatni , District Khurda, Bhubaneswar , Odisha 752050 , India
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Du L, Lan X, Yan Z, Zhu R, Phillips DL. Time-Resolved Spectroscopic Study of N, N-Di(4-bromo)nitrenium Ions in Selected Solutions. Molecules 2018; 23:E3182. [PMID: 30513911 PMCID: PMC6321521 DOI: 10.3390/molecules23123182] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 11/26/2018] [Accepted: 11/30/2018] [Indexed: 12/02/2022] Open
Abstract
Nitrenium ions are important reactive intermediates in chemistry and biology. In this work, femtosecond and nanosecond transient absorption (fs-TA and ns-TA) along with nanosecond time-resolved resonance Raman (ns-TR³) experiments were employed to examine the photochemical pathways of N-(4,4'-dibromodiphenylamino)-2,4,6-trimethylpyridinium BF₄- (salt (DN) from just absorption of a photon of light to the production of the important N,N-di(4-bromophenyl)nitrenium ion 2. In acetonitrile (MeCN), the formation of halogenated diarylnitrenium ion 2 was observed within 4 ps, showing the vibrational spectra with strong intensity. The nucleophilic adduct reaction of ion 2 with H₂O was also examined in aqueous solutions. The direct detection of the unique ortho adduct intermediate 3 shows that there is an efficient and exclusive reaction pathway for 2 with H₂O. The results shown in this paper give new characterization of 2, which can be used to design time-resolved spectroscopy investigations of covalent addition reactions of nitrenium ions with other molecules in future studies.
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Affiliation(s)
- Lili Du
- Department of Chemistry, The University of Hong Kong, Hong Kong S.A.R., China.
- Institute of Life Sciences, Jiangsu University, Zhenjiang 212013, China.
| | - Xin Lan
- Department of Chemistry, The University of Hong Kong, Hong Kong S.A.R., China.
| | - Zhiping Yan
- Department of Chemistry, The University of Hong Kong, Hong Kong S.A.R., China.
| | - Ruixue Zhu
- Department of Chemistry, The University of Hong Kong, Hong Kong S.A.R., China.
- School of Physical Science and Technology, Shanghai Tech University, Shanghai 201210, China.
| | - David Lee Phillips
- Department of Chemistry, The University of Hong Kong, Hong Kong S.A.R., China.
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9
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Brown TA, Hosseini-Nassab N, Chen H, Zare RN. Observation of electrochemically generated nitrenium ions by desorption electrospray ionization mass spectrometry. Chem Sci 2016; 7:329-332. [PMID: 28791096 PMCID: PMC5518571 DOI: 10.1039/c5sc02939b] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2015] [Accepted: 10/08/2015] [Indexed: 01/18/2023] Open
Abstract
We report the observation of the electrochemically generated nitrenium ions of 4,4'-dimethyoxydiphenylamine and di-p-tolylamine in solution by mass spectrometry. This setup takes inspiration from desorption electrospray ionization mass spectrometry to sample directly from the surface of a rotating waterwheel working electrode for mass spectrometric analysis. Detection of the 4,4'-dimethyoxydiphenylamine nitrenium ion was expected based upon para-methoxy resonance stabilization, whereas observation of the di-p-tolylamine nitrenium ion might be unexpected because resonance stabilization from the para-substituted position is unavailable. However, the short timescale analysis of the setup allows for the isolation of the di-p-tolylamine nitrenium ion, which is electrogenerated in solution and detected mass spectrometrically.
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Affiliation(s)
- Timothy A Brown
- Department of Chemistry , Stanford University , Stanford , CA 94305-5080 , USA .
| | | | - Hao Chen
- Center for Intelligent Chemical Instrumentation , Department of Chemistry and Biochemistry and Edison Biotechnology Institute , Ohio University , Athens , OH 45701-2979 , USA .
| | - Richard N Zare
- Department of Chemistry , Stanford University , Stanford , CA 94305-5080 , USA .
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10
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Xue J, Li Y, Du L, Du Y, Tang W, Zheng X, Phillips DL. Direct Observation of 4-Phenoxyphenylnitrenium Ion: A Transient Absorption and Transient Resonance Raman Study. J Phys Chem B 2015; 119:14720-7. [PMID: 26503835 DOI: 10.1021/acs.jpcb.5b07218] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Femtosecond (fs) and nanosecond (ns) transient absorption (TA) and single pulse transient resonance Raman spectroscopic investigation of the intermediates after laser photolysis of 4-phenoxyphenyl azide in acetonitrile and mixed aqueous solution is reported. fs-TA results show that the singlet 4-phenoxyphenylnitrene was produced immediately after photolysis of the azide. Then, the singlet nitrene underwent intersystem crossing (ISC) and ring expansion to generate triplet nitrene and ketenimine in acetonitrile with t = 346 ps or protonation in mixed aqueous solution with t = 37 ps, respectively, a little slower than the counterparts of the methoxy one (108 and 5.4 ps for ISC and protonation processes, respectively). The transient Raman spectrum combined density functional theory (DFT) calculation predicting the structure and vibrational frequencies suggested that phenoxyphenylnitrenium ion has a comparable quinoidal character to that of methoxy- and ethoxy-phenylnitrenium ions. All of these results indicated that the phenoxy substitution has some impact on the reactivity of phenylnitrene but a slight influence on the structure of phenylnitrenium ion.
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Affiliation(s)
- Jiadan Xue
- Engineering Research Center for Eco-Dyeing & Finishing of Textiles, Ministry of Education, Zhejiang Sci-Tech University , Hangzhou, 310018, China.,Department of Chemistry, Zhejiang Sci-Tech University , Hangzhou, 310018, China
| | - Yafang Li
- Department of Chemistry, Zhejiang Sci-Tech University , Hangzhou, 310018, China
| | - Lili Du
- Department of Chemistry, The University of Hong Kong , Hong Kong, S. A. R., China
| | - Yong Du
- Centre for THz Research, China Jiliang University , Hangzhou, 310018, China
| | - Wenjian Tang
- School of Pharmacy, Anhui Medical University , Hefei, 230032, China
| | - Xuming Zheng
- Department of Chemistry, Zhejiang Sci-Tech University , Hangzhou, 310018, China
| | - David Lee Phillips
- Department of Chemistry, The University of Hong Kong , Hong Kong, S. A. R., China
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Epishina MA, Kulikov AS, Ignat’ev NV, Schulte M, Makhova NN. Efficient synthesis of tertiary acyclic amides by the Chapman rearrangement of aryl benzimidates in ionic liquids. MENDELEEV COMMUNICATIONS 2015. [DOI: 10.1016/j.mencom.2015.03.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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12
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Barba F, Batanero B, Tissaoui K, Raouafi N, Boujlel K. Cathodic reduction of diazonium salts in aprotic medium. Electrochem commun 2010. [DOI: 10.1016/j.elecom.2010.05.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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14
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Macchia GL, Gagliardi L, Carlson GS, Jay AN, Davis E, Cramer CJ. Theoretical prediction of linear free energy relationships using proton nucleomers. J PHYS ORG CHEM 2008. [DOI: 10.1002/poc.1297] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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