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Grossert JS, White RL. Fragmentation reactions of protonated α,ω-diamino carboxylic acids: The importance of functional group interactions. JOURNAL OF MASS SPECTROMETRY : JMS 2021; 56:e4770. [PMID: 34120394 DOI: 10.1002/jms.4770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 05/12/2021] [Accepted: 05/17/2021] [Indexed: 06/12/2023]
Abstract
Protonated members of a homologous series of biologically significant α,ω-diamino carboxylic acids were subjected to collision induced dissociation (CID). The resulting fragmentation patterns were studied using isotopic labeling, quantum mechanical computations, and pseudo MS3 experiments conducted primarily on an ion trap mass spectrometer. Each protonated α,ω-diamino acid showed a primary neutral loss of either ammonia or water; a clear explanation was developed for the observed variation of the two losses within the series. Protonated 2,3-diaminopropanoic acid, 2,4-diaminobutanoic acid, and 2,7-diaminoheptanoic acid gave secondary losses of water, carbon monoxide, and a loss of water plus carbon monoxide, respectively. In the parallel pathways characterized for the fragmentations of protonated ornithine and lysine, the α-nitrogen of the diamino acid was maintained in the cyclic iminium product formed by successive losses of NH3 and (H2 O + CO), whereas the side-chain nitrogen was retained by consecutive losses of H2 O and (CO, NH3 ). The 1-piperideine ion from protonated lysine was fragmented further, losing ethylene from carbons 4 and 5. Protonated 2,6-diaminopimelic acid fragmented by analogous reactions. Detailed mechanistic schemes for the fragmentation of both protonated 2,3-diaminopropanoic and ornithine were generated from MP2/DFT computations. This work highlights the participation of the side-chain amino group, which distinguishes the gas-phase chemistry of protonated α,ω-diamino acids from the well-documented fragmentation reactions of protonated α-amino acids bearing a hydrogen atom or an alkyl side chain. In general, the results further illustrate the importance of intramolecular separations affecting the specific interactions between functional groups leading to the fragmentation of multifunctional ions.
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Affiliation(s)
- J Stuart Grossert
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Robert L White
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada
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Computational Study of Selected Amine and Lactam N-Oxides Including Comparisons of N-O Bond Dissociation Enthalpies with Those of Pyridine N-Oxides. Molecules 2020; 25:molecules25163703. [PMID: 32823830 PMCID: PMC7463812 DOI: 10.3390/molecules25163703] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 08/03/2020] [Accepted: 08/05/2020] [Indexed: 11/17/2022] Open
Abstract
A computational study of the structures and energetics of amine N-oxides, including pyridine N-oxides, trimethylamine N-oxide, bridgehead bicyclic amine N-oxides, and lactam N-oxides, allowed comparisons with published experimental data. Most of the computations employed the B3LYP/6-31G* and M06/6-311G+(d,p) models and comparisons were also made between the results of the HF 6-31G*, B3LYP/6-31G**, B3PW91/6-31G*, B3PW91/6-31G**, and the B3PW91/6-311G+(d,p) models. The range of calculated N-O bond dissociation energies (BDE) (actually enthalpies) was about 40 kcal/mol. Of particular interest was the BDE difference between pyridine N-oxide (PNO) and trimethylamine N-oxide (TMAO). Published thermochemical and computational (HF 6-31G*) data suggest that the BDE of PNO was only about 2 kcal/mol greater than that of TMAO. The higher IR frequency for N-O stretch in PNO and its shorter N-O bond length suggest a greater difference in BDE values, predicted at 10–14 kcal/mol in the present work. Determination of the enthalpy of sublimation of TMAO, or at least the enthalpy of fusion and estimation of the enthalpy of vaporization might solve this dichotomy. The “extra” resonance stabilization in pyridine N-oxide relative to pyridine was consistent with the 10–14 kcal/mol increase in BDE, relative to TMAO, and was about half the “extra” stabilization in phenoxide, relative to phenol or benzene. Comparison of pyridine N-oxide with its acyclic model nitrone (“Dewar-Breslow model”) indicated aromaticity slightly less than that of pyridine.
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Deshmukh SD, Easterling LF, Manheim JM, LiBretto NJ, Weideman KG, Miller JT, Kenttämaa HI, Agrawal R. Analyzing and Tuning the Chalcogen-Amine-Thiol Complexes for Tailoring of Chalcogenide Syntheses. Inorg Chem 2020; 59:8240-8250. [PMID: 32441926 DOI: 10.1021/acs.inorgchem.0c00597] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The amine-thiol solvent system has been used extensively to synthesize metal chalcogenide thin films and nanoparticles because of its ability to dissolve various metal and chalcogen precursors. While previous studies of this solvent system have focused on understanding the dissolution of metal precursors, here we provide an in-depth investigation of the dissolution of chalcogens, specifically Se and Te. Analytical techniques, including Raman, X-ray absorption, and NMR spectroscopy and high-resolution tandem mass spectrometry, were used to identify pathways for Se and Te dissolution in butylamine-ethanethiol and ethylenediamine-ethanethiol solutions. Se in monoamine-monothiol solutions was found to form ionic polyselenides free of thiol ligands, while in diamine-monothiol solutions, thiol coordination with polyselenides was predominately observed. When the relative concentration of thiol is increased to that of Se, the chain length of polyselenide species was observed to shorten. Analysis of Te dissolution in diamine-thiol solutions also suggested the formation of relatively unstable thiol-coordinated Te ions. This instability of Te ions was found to be reduced by codissolving Te with Se in diamine-thiol solutions. Analysis of the codissolved solutions revealed the presence of atomic interaction between Se and Te through the identification of Se-Te bonds. This new understanding then provided a new route to dissolve otherwise insoluble Te in butylamine-ethanethiol solutions by taking advantage of the Se2- nucleophile. Finally, the knowledge gained for chalcogen dissolutions in this solvent system allowed for controlled alloying of Se and Te in PbSenTe1-n material and also provided a general knob to alter various metal chalcogenide material syntheses.
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Affiliation(s)
- Swapnil D Deshmukh
- Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
| | - Leah F Easterling
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Jeremy M Manheim
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Nicole J LiBretto
- Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
| | - Kyle G Weideman
- Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
| | - Jeffrey T Miller
- Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
| | - Hilkka I Kenttämaa
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Rakesh Agrawal
- Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
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Muhammad S, Javed MN, Ali FI, Bari A, Hashmi IA. Supramolecular polymeric aggregation behavior and its impact on catalytic properties of imidazolium based hydrophilic ionic liquids. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2019.112372] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Chemistry of Bridged Lactams: Recent Developments. Molecules 2019; 24:molecules24020274. [PMID: 30642094 PMCID: PMC6359620 DOI: 10.3390/molecules24020274] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 01/09/2019] [Accepted: 01/10/2019] [Indexed: 12/15/2022] Open
Abstract
Bridged lactams represent the most effective and wide-ranging method of constraining the amide bond in a non-planar conformation. A previous comprehensive review on this topic was published in 2013 (Chem. Rev.2013, 113, 5701–5765). In the present review, which is published as a part of the Special Issue on Amide Bond Activation, we present an overview of the recent developments in the field of bridged lactams that have taken place in the last five years and present a critical assessment of the current status of bridged lactams in synthetic and physical organic chemistry. This review covers the period from 2014 until the end of 2018 and is intended as an update to Chem. Rev.2013, 113, 5701–5765. In addition to bridged lactams, the review covers recent advances in the chemistry of bridged sultams, bridged enamines and related non-planar structures.
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Vatsadze SZ, Loginova YD, dos Passos Gomes G, Alabugin IV. Stereoelectronic Chameleons: The Donor–Acceptor Dichotomy of Functional Groups. Chemistry 2016; 23:3225-3245. [DOI: 10.1002/chem.201603491] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2016] [Indexed: 01/28/2023]
Affiliation(s)
- Sergey Z. Vatsadze
- Department of Organic Chemistry, Faculty of Chemistry Lomonosov Moscow State University Leninsky gory, 1, 3 Moscow Russia
| | - Yulia D. Loginova
- Department of Organic Chemistry, Faculty of Chemistry Lomonosov Moscow State University Leninsky gory, 1, 3 Moscow Russia
| | - Gabriel dos Passos Gomes
- Department of Chemistry and Biochemistry Florida State University 95 Chieftan Way Tallahassee USA
| | - Igor V. Alabugin
- Department of Chemistry and Biochemistry Florida State University 95 Chieftan Way Tallahassee USA
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Pace V, Holzer W, Meng G, Shi S, Lalancette R, Szostak R, Szostak M. Structures of Highly Twisted Amides Relevant to Amide N−C Cross-Coupling: Evidence for Ground-State Amide Destabilization. Chemistry 2016; 22:14494-8. [DOI: 10.1002/chem.201603543] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Indexed: 12/18/2022]
Affiliation(s)
- Vittorio Pace
- Department of Pharmaceutical Chemistry; Faculty of Life Sciences; University of Vienna; Althanstrasse 14 Vienna 1090 Austria
| | - Wolfgang Holzer
- Department of Pharmaceutical Chemistry; Faculty of Life Sciences; University of Vienna; Althanstrasse 14 Vienna 1090 Austria
| | - Guangrong Meng
- Department of Chemistry; Rutgers University; 73 Warren Street Newark NJ 07102 United States
| | - Shicheng Shi
- Department of Chemistry; Rutgers University; 73 Warren Street Newark NJ 07102 United States
| | - Roger Lalancette
- Department of Chemistry; Rutgers University; 73 Warren Street Newark NJ 07102 United States
| | - Roman Szostak
- Department of Chemistry; Wroclaw University; F. Joliot-Curie 14 Wroclaw 50-383 Poland
| | - Michal Szostak
- Department of Chemistry; Rutgers University; 73 Warren Street Newark NJ 07102 United States
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Szostak R, Shi S, Meng G, Lalancette R, Szostak M. Ground-State Distortion in N-Acyl-tert-butyl-carbamates (Boc) and N-Acyl-tosylamides (Ts): Twisted Amides of Relevance to Amide N–C Cross-Coupling. J Org Chem 2016; 81:8091-4. [DOI: 10.1021/acs.joc.6b01560] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Roman Szostak
- Department
of Chemistry, Wroclaw University, F. Joliot-Curie 14, Wroclaw 50-383, Poland
| | - Shicheng Shi
- Department
of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, United States
| | - Guangrong Meng
- Department
of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, United States
| | - Roger Lalancette
- Department
of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, United States
| | - Michal Szostak
- Department
of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, United States
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Kubik Ł, Struck-Lewicka W, Kaliszan R, Wiczling P. Simultaneous determination of hydrophobicity and dissociation constant for a large set of compounds by gradient reverse phase high performance liquid chromatography–mass spectrometry technique. J Chromatogr A 2015; 1416:31-7. [DOI: 10.1016/j.chroma.2015.09.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 09/01/2015] [Accepted: 09/02/2015] [Indexed: 10/23/2022]
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Mass spectrometry study of N-alkylbenzenesulfonamides with potential antagonist activity to potassium channels. Amino Acids 2015; 48:445-59. [PMID: 26395182 DOI: 10.1007/s00726-015-2099-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 09/09/2015] [Indexed: 10/23/2022]
Abstract
Herein, we report the synthesis and mass spectrometry studies of several N-alkylbenzenesulfonamides structurally related to sulfanilic acid. The compounds were synthesized using a modified Schotten-Baumann reaction coupled with Meisenheimer arylation. Sequential mass spectrometry by negative mode electrospray ionization (ESI(-)-MS/MS) showed the formation of sulfoxylate anion (m/z 65) observed in the mass spectrum of p-chloro-N-alkylbenzenesulfonamides. Investigation of the unexpected loss of two water molecules, as observed by electron ionization mass spectrometry (EI-MS) analysis of p-(N-alkyl)lactam sulfonamides, led to the proposal of corresponding fragmentation pathways. These compounds showed loss of neutral iminosulfane dioxide molecule (M-79) with formation of ions observed at m/z 344 and 377. These ions were formed by rearrangement on ESI(+)-MS/MS analysis. Some of the molecules showed antagonistic activity against Kv3.1 voltage-gated potassium channels.
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Szostak R, Aubé J, Szostak M. Determination of Structures and Energetics of Small- and Medium-Sized One-Carbon-Bridged Twisted Amides using ab Initio Molecular Orbital Methods: Implications for Amidic Resonance along the C–N Rotational Pathway. J Org Chem 2015; 80:7905-27. [DOI: 10.1021/acs.joc.5b00881] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Roman Szostak
- Department of Chemistry, Wroclaw University, F. Joliot-Curie 14, Wroclaw 50-383, Poland
| | - Jeffrey Aubé
- Division of Chemical
Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Michal Szostak
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, United States
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