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Frere GA, Hasabnis A, Francisco CB, Suleiman M, Alimowska O, Rahmatullah R, Gould J, Su CYC, Voznyy O, Gunning PT, Basso EA, Prosser RS. Next-Generation Tags for Fluorine Nuclear Magnetic Resonance: Designing Amplification of Chemical Shift Sensitivity. J Am Chem Soc 2024; 146:3052-3064. [PMID: 38279916 DOI: 10.1021/jacs.3c09730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2024]
Abstract
Fluorine NMR is a highly sensitive technique for delineating the conformational states of biomolecules and has shown great utility in drug screening and in understanding protein function. Current fluorinated protein tags leverage the intrinsic chemical shift sensitivity of the 19F nucleus to detect subtle changes in protein conformation and topology. This chemical shift sensitivity can be amplified by embedding the fluorine or trifluoromethyl reporter within a pyridone. Due to their polarizability and rapid tautomerization, pyridones exhibit a greater range of electron delocalization and correspondingly greater 19F NMR chemical shift dispersion. To assess the chemical shift sensitivity of these tautomeric probes to the local environment, 19F NMR spectra of all possible monofluorinated and trifluoromethyl-tagged versions of 2-pyridone were recorded in methanol/water mixtures ranging from 100% methanol to 100% water. 4-Fluoro-2-pyridone and 6-(trifluoromethyl)-2-pyridone (6-TFP) displayed the greatest sensitivity of the monofluorinated and trifluoromethylated pyridones, exceeding that of known conventional CF3 reporters. To evaluate the utility of tautomeric pyridone tags for 19F NMR of biomolecules, the alpha subunit of the stimulatory G protein (Gsα) and human serum albumin (HSA) were each labeled with a thiol-reactive derivative of 6-TFP and the spectra were recorded as a function of various adjuvants and drugs. The tautomeric tag outperformed the conventional tag, 2-bromo-N-(4-(trifluoromethyl)phenyl)acetamide through the improved resolution of several functional states.
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Affiliation(s)
- Geordon A Frere
- Department of Chemistry, University of Toronto, CPS, UTM, 3359 Mississauga Rd, Mississauga, ON L5L 1C6, Canada
| | - Advait Hasabnis
- Department of Chemistry, University of Toronto, CPS, UTM, 3359 Mississauga Rd, Mississauga, ON L5L 1C6, Canada
| | - Camila B Francisco
- Department of Chemistry, University of Toronto, CPS, UTM, 3359 Mississauga Rd, Mississauga, ON L5L 1C6, Canada
- Department of Chemistry, State University of Maringá, 5790, Maringá 87020-900, Brazil
| | - Motasem Suleiman
- Department of Chemistry, University of Toronto, CPS, UTM, 3359 Mississauga Rd, Mississauga, ON L5L 1C6, Canada
| | - Olga Alimowska
- Department of Chemistry, University of Toronto, CPS, UTM, 3359 Mississauga Rd, Mississauga, ON L5L 1C6, Canada
| | - Rima Rahmatullah
- Department of Chemistry, University of Toronto, CPS, UTM, 3359 Mississauga Rd, Mississauga, ON L5L 1C6, Canada
| | - Jerome Gould
- Department of Chemistry, University of Toronto, CPS, UTM, 3359 Mississauga Rd, Mississauga, ON L5L 1C6, Canada
| | - Celia Yi-Chia Su
- Department of Chemistry, University of Toronto, CPS, UTM, 3359 Mississauga Rd, Mississauga, ON L5L 1C6, Canada
| | - Oleksandr Voznyy
- Department of Chemistry, University of Toronto, CPS, UTM, 3359 Mississauga Rd, Mississauga, ON L5L 1C6, Canada
| | - Patrick T Gunning
- Department of Chemistry, University of Toronto, CPS, UTM, 3359 Mississauga Rd, Mississauga, ON L5L 1C6, Canada
| | - Ernani A Basso
- Department of Chemistry, State University of Maringá, 5790, Maringá 87020-900, Brazil
| | - Robert S Prosser
- Department of Chemistry, University of Toronto, CPS, UTM, 3359 Mississauga Rd, Mississauga, ON L5L 1C6, Canada
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2
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Nerella SG, Telu S, Liow JS, Jenkins MD, Zoghbi SS, Gomez JL, Michaelides M, Eldridge MAG, Richmond BJ, Innis RB, Pike VW. Synthesis and preclinical evaluation of [ 11C]uPSEM792 for PSAM 4-GlyR based chemogenetics. Sci Rep 2024; 14:1886. [PMID: 38253691 PMCID: PMC10803328 DOI: 10.1038/s41598-024-51307-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 01/01/2024] [Indexed: 01/24/2024] Open
Abstract
Chemogenetic tools are designed to control neuronal signaling. These tools have the potential to contribute to the understanding of neuropsychiatric disorders and to the development of new treatments. One such chemogenetic technology comprises modified Pharmacologically Selective Actuator Modules (PSAMs) paired with Pharmacologically Selective Effector Molecules (PSEMs). PSAMs are receptors with ligand-binding domains that have been modified to interact only with a specific small-molecule agonist, designated a PSEM. PSAM4 is a triple mutant PSAM derived from the α7 nicotinic receptor (α7L131G,Q139L,Y217F). Although having no constitutive activity as a ligand-gated ion channel, PSAM4 has been coupled to the serotonin 5-HT3 receptor (5-HT3R) and to the glycine receptor (GlyR). Treatment with the partner PSEM to activate PSAM4-5-HT3 or PSAM4-GlyR, causes neuronal activation or silencing, respectively. A suitably designed radioligand may enable selective visualization of the expression and location of PSAMs with positron emission tomography (PET). Here, we evaluated uPSEM792, an ultrapotent PSEM for PSAM4-GlyR, as a possible lead for PET radioligand development. We labeled uPSEM792 with the positron-emitter, carbon-11 (t1/2 = 20.4 min), in high radiochemical yield by treating a protected precursor with [11C]iodomethane followed by base deprotection. PET experiments with [11C]uPSEM792 in rodents and in a monkey transduced with PSAM4-GlyR showed low peak radioactivity uptake in brain. This low uptake was probably due to high polarity of the radioligand, as evidenced by physicochemical measurements, and to the vulnerability of the radioligand to efflux transport at the blood-brain barrier. These findings can inform the design of a more effective PSAM4 based PET radioligand, based on the uPSEM792 chemotype.
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Affiliation(s)
- Sridhar Goud Nerella
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Sanjay Telu
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA.
| | - Jeih-San Liow
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Madeline D Jenkins
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Sami S Zoghbi
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Juan L Gomez
- Biobehavioral Imaging and Molecular Neuropsychopharmacology Unit, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, USA
| | - Michael Michaelides
- Biobehavioral Imaging and Molecular Neuropsychopharmacology Unit, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, USA
| | - Mark A G Eldridge
- Laboratory of Neuropsychology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Barry J Richmond
- Laboratory of Neuropsychology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Robert B Innis
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Victor W Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA.
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3
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Tamaddon F, Maddah-Roodan S. Advanced Guareschi-Thorpe synthesis of pyridines in green buffer, and pH-controlled aqueous medium with ammonium carbonate. RSC Adv 2023; 13:24846-24853. [PMID: 37608967 PMCID: PMC10440631 DOI: 10.1039/d3ra04590k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 08/14/2023] [Indexed: 08/24/2023] Open
Abstract
Hydroxy-cyanopyridines are easily synthesized via an advanced version of the Guareschi-Thorpe reaction by either three-component condensation of alkyl cyanoacetate or cyanoacetamide with 1,3-dicarbonyls and ammonium carbonate in an aqueous medium. Reactions proceed productively to give the desired products in high yields. Simple mechanistic monitoring showed the role of (NH4)2CO3 as both a nitrogen source for the pyridine ring and the reaction promoter. This new multicomponent approach for pyridine synthesis is inexpensive, user-friendly, and eco-friendly, while green buffer conditions, versatility, precipitation of products in the reaction medium, and simple work-up are extra advantages.
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Affiliation(s)
- Fatemeh Tamaddon
- Department of Chemistry, Faculty of Science, Yazd University Yazd 89195-741 Iran
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4
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Hurtado-Rodríguez D, Salinas-Torres A, Rojas H, Becerra D, Castillo JC. Bioactive 2-pyridone-containing heterocycle syntheses using multicomponent reactions. RSC Adv 2022; 12:34965-34983. [PMID: 36540221 PMCID: PMC9727751 DOI: 10.1039/d2ra07056a] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 11/30/2022] [Indexed: 08/24/2023] Open
Abstract
2-Pyridone-containing heterocycles are considered privileged scaffolds in drug discovery due to their behavior as hydrogen bond donors and/or acceptors and nonpeptidic mimics, and remarkable physicochemical properties such as metabolic stability, solubility in water, and lipophilicity. This review provides a comprehensive overview of multicomponent reactions (MCRs) for the synthesis of 2-pyridone-containing heterocycles. In particular, it covers the articles published from 1999 to date related to anticancer, antibacterial, antifungal, anti-inflammatory, α-glucosidase inhibitor, and cardiotonic activities of 2-pyridone-containing heterocycles obtained exclusively by an MCR. The discussion focuses on bioactivity data, synthetic approaches, plausible reaction mechanisms, and molecular docking simulations to facilitate comparison and underscore the applications of the 2-pyridone motif in drug discovery and medicinal chemistry. We also present our conclusions and outlook for the future.
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Affiliation(s)
- Diana Hurtado-Rodríguez
- Grupo de Catálisis de la UPTC, Escuela de Ciencias Química, Universidad Pedagógica y Tecnológica de Colombia Avenida Central del Norte 39-115 Tunja Colombia
| | - Angélica Salinas-Torres
- Grupo de Catálisis de la UPTC, Escuela de Ciencias Química, Universidad Pedagógica y Tecnológica de Colombia Avenida Central del Norte 39-115 Tunja Colombia
| | - Hugo Rojas
- Grupo de Catálisis de la UPTC, Escuela de Ciencias Química, Universidad Pedagógica y Tecnológica de Colombia Avenida Central del Norte 39-115 Tunja Colombia
| | - Diana Becerra
- Grupo de Catálisis de la UPTC, Escuela de Ciencias Química, Universidad Pedagógica y Tecnológica de Colombia Avenida Central del Norte 39-115 Tunja Colombia
| | - Juan-Carlos Castillo
- Grupo de Catálisis de la UPTC, Escuela de Ciencias Química, Universidad Pedagógica y Tecnológica de Colombia Avenida Central del Norte 39-115 Tunja Colombia
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Ida S, Wilson P, Neppolian B, Sathish M, Mahammed Shaheer AR, Ravi P. Tuning the type of nitrogen on N-RGO supported on N-TiO 2 under ultrasonication/hydrothermal treatment for efficient hydrogen evolution - A mechanistic overview. ULTRASONICS SONOCHEMISTRY 2020; 64:104866. [PMID: 31983561 DOI: 10.1016/j.ultsonch.2019.104866] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 11/04/2019] [Accepted: 11/05/2019] [Indexed: 06/10/2023]
Abstract
Efficient hydrogen production through water splitting has been the challenging task to be achieved in the present context of energy crisis. Among the various catalysts employed, nitrogen doped Titanium dioxide/Reduced graphene oxide (N-TiO2/RGO) nanocomposite has been established to be a promising photocatalytic material for this purpose. However, nuances of doping nitrogen on TiO2 and the type of nitrogen (pyridinic, pyrrolic and graphitic) stabilized on RGO responsible for facilitating the H2 production has not yet been addressed mechanistically. In the present investigation, an attempt has been made to synthesise N-Titanium dioxide/N-Reduced graphene oxide (NTNG) nanocomposite under ultrasonication followed by hydrothermal treatment. A stainlesssteel ultrasonic bath, of 6.5 L tank size (LxBxH) 300 × 150 × 150 mm, was used for ultrasonic treatments. The transducers located at the bottom of the ultrasonic bath generate a frequency of 40 kHz with maximum power of 200 W. A mechanism has been proposed including the nuances of formation and the stabilisation of each type of nitrogen on N-RGO as a function of ultrasonication time. The present work supports the stabilization of a given type of nitrogen on RGO through keto enol tautomerism. XPS and FTIR studies have been undertaken to identify the different types of nitrogen doping and the presence of functional groups respectively. XRD, UV-Vis DRS and PL investigations have been made to establish morphological profile and band gap structure of the nanocomposite. It was observed that pyrrolic type nitrogen stabilized on N-RGO augments the efficiency of photocatalytic activity through hydrogen production by water splitting.
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Affiliation(s)
- S Ida
- Department of Chemistry, Madras Christian College (Autonomous), University of Madras, Chennai 600005, Tamil Nadu, India
| | - P Wilson
- Department of Chemistry, Madras Christian College (Autonomous), University of Madras, Chennai 600005, Tamil Nadu, India.
| | - B Neppolian
- SRM Research Institute, SRM University, Kattankulathur, Chennai 603203, Tamil Nadu, India
| | - M Sathish
- Functional Materials Division, CSIR-Central Electrochemical Research Institute, Karaikudi 630003, Tamilnadu, India
| | - A R Mahammed Shaheer
- SRM Research Institute, SRM University, Kattankulathur, Chennai 603203, Tamil Nadu, India
| | - P Ravi
- Functional Materials Division, CSIR-Central Electrochemical Research Institute, Karaikudi 630003, Tamilnadu, India
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6
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Timmerman JC, Laulhé S, Widenhoefer RA. Gold(I)-Catalyzed Intramolecular Hydroamination of Unactivated Terminal and Internal Alkenes with 2-Pyridones. Org Lett 2017; 19:1466-1469. [DOI: 10.1021/acs.orglett.7b00450] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jacob C. Timmerman
- French Family Science Center, Duke University, Durham, North Carolina 27708, United States
| | - Sébastien Laulhé
- French Family Science Center, Duke University, Durham, North Carolina 27708, United States
| | - Ross A. Widenhoefer
- French Family Science Center, Duke University, Durham, North Carolina 27708, United States
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7
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Peng CS, Tokmakoff A. Identification of Lactam-Lactim Tautomers of Aromatic Heterocycles in Aqueous Solution Using 2D IR Spectroscopy. J Phys Chem Lett 2012; 3:3302-3306. [PMID: 23227298 PMCID: PMC3516185 DOI: 10.1021/jz301706a] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The tautomerism of aromatic heterocycles is of great interest because it directly affects their chemical properties and biological function. The tautomerism of 2-pyridone, 6-chloro-2-pyridone, and 4-pyrimidinone have been examined in D(2)O using FTIR, two-dimensional IR (2D IR) spectroscopy and density functional theory (DFT) calculations. Using the 2D IR cross-peak patterns, the lactim tautomer of 6-chloro-2-pyridone was separated from the lactam tautomer, and its population was observed to increase with temperature. The equilibrium constant of [lac-tam]/[lactim] was determined to be 2.1 at room temperature for 6-chloro-2-pyridone. Similarly, the N1H and N3H lactam tautomers of 4-pyrimidinone were identified with 2D IR. To assign the vibrational modes of different tautomers, DFT calculations of these chemical species were performed with explicit water molecules, and the hydration effects on the vibrational frequencies and intensities were established.
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8
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The influence of secondary interactions on complex stability and double proton transfer reaction in 2-[1H]-pyridone/2-hydroxypyridine dimers. J Mol Model 2010; 17:2491-500. [PMID: 21193938 DOI: 10.1007/s00894-010-0934-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Accepted: 12/09/2010] [Indexed: 10/18/2022]
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9
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Yang M, Szyc Ł, Dreyer J, Nibbering ETJ, Elsaesser T. The Hydrogen-Bonded 2-Pyridone Dimer Model System. 2. Femtosecond Mid-Infrared Pump−Probe Study. J Phys Chem A 2010; 114:12195-201. [PMID: 21038900 DOI: 10.1021/jp108096y] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Ming Yang
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, D-12489 Berlin, Germany
| | - Łukasz Szyc
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, D-12489 Berlin, Germany
| | - Jens Dreyer
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, D-12489 Berlin, Germany
| | - Erik T. J. Nibbering
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, D-12489 Berlin, Germany
| | - Thomas Elsaesser
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, D-12489 Berlin, Germany
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10
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Siddle JS, Batsanov AS, Caldwell ST, Cooke G, Bryce MR. Divergent synthesis of arylated pyridin-2(1H)-one derivatives via metal-catalysed cross-coupling processes. Tetrahedron 2010. [DOI: 10.1016/j.tet.2010.05.108] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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11
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12
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Tsuchida N, Yamabe S. Reaction paths of tautomerization between hydroxypyridines and pyridones. J Phys Chem A 2007; 109:1974-80. [PMID: 16833531 DOI: 10.1021/jp040451w] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Tautomerization paths of 2(and 4)-hydroxypyridine (called here HP) to 2(and 4)-pyridone (called here PY) with water molecules were investigated by the use of density functional theory calculations. Potential energies were compared for a number of water molecules. The 2-HP molecule was found to be isomerized most readily and concertedly to the 2-PY one via proton relays with two water molecules. The reaction pattern is invariant even when outer water molecules are added. The 4-HP(H(2)O)(n) --> 4-PY(H(2)O)(n) reaction model did not give small activation energies. However, a reaction of (4-HP)(2)(H(2)O)(2) --> (4-PY)(2)(H(2)O)(2) was found to occur readily through a transient ion-pair intermediate. The conversion processes of (2-PY)(2) to the tautomerization reacting system were discussed. The hydrogen-bond directionality regulates the tautomerization paths.
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Affiliation(s)
- Noriko Tsuchida
- Department of Chemistry, Nara University of Education, Takabatake-cho, Nara 630-8528, Japan
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13
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Metzler DE. Tautomerism in pyridoxal phosphate and in enzymatic catalysis. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 50:1-40. [PMID: 386717 DOI: 10.1002/9780470122952.ch1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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14
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Lima MCP, Coutinho K, Canuto S, Rocha WR. Reaction Mechanism and Tautomeric Equilibrium of 2-Mercaptopyrimidine in the Gas Phase and in Aqueous Solution: A Combined Monte Carlo and Quantum Mechanics Study. J Phys Chem A 2006; 110:7253-61. [PMID: 16737277 DOI: 10.1021/jp060821b] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A combined Monte Carlo and quantum mechanical study was carried out to analyze the tautomeric equilibrium of 2-mercaptopyrimidine in the gas phase and in aqueous solution. Second- and fourth-order Møller-Plesset perturbation theory calculations indicate that in the gas phase thiol (Pym-SH) is more stable than the thione (Pym-NH) by ca. 8 kcal/mol. In aqueous solution, thermodynamic perturbation theory implemented on a Monte Carlo NpT simulation indicates that both the differential enthalpy and Gibbs free energy favor the thione form. The calculated differential enthalpy is DeltaH(SH)(-->)(NH)(solv) = -1.7 kcal/mol and the differential Gibbs free energy is DeltaG(SH)(-->)(NH)(solv) = -1.9 kcal/mol. Analysis is made of the contribution of the solute-solvent hydrogen bonds and it is noted that the SH group in the thiol and NH group in the thione tautomers act exclusively as a hydrogen bond donor in aqueous solution. The proton transfer reaction between the tautomeric forms was also investigated in the gas phase and in aqueous solution. Two distinct mechanisms were considered: a direct intramolecular transfer and a water-assisted mechanism. In the gas phase, the intramolecular transfer leads to a large energy barrier of 34.4 kcal/mol, passing through a three-center transition state. The proton transfer with the assistance of one water molecule decreases the energy barrier to 17.2 kcal/mol. In solution, these calculated activation barriers are, respectively, 32.0 and 14.8 kcal/mol. The solvent effect is found to be sizable but it is considerably more important as a participant in the water-assisted mechanism than the solvent field of the solute-solvent interaction. Finally, the calculated total Gibbs free energy is used to estimate the equilibrium constant.
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Affiliation(s)
- Maria Carolina P Lima
- Departamento de Química Fundamental - CCEN, Universidade Federal de Pernambuco, Cidade Universitaria, Recife, PE, Brazil
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Stanovnik B, Tišler M, Katritzky AR, Denisko OV. The Tautomerism of Heterocycles: Substituent Tautomerism of Six-Membered Ring Heterocycles. ADVANCES IN HETEROCYCLIC CHEMISTRY 2006. [DOI: 10.1016/s0065-2725(06)91001-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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16
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Synthesis of Pyrido[2,3-b]pyrazine Derivatives (Part I). JOURNAL OF THE KOREAN CHEMICAL SOCIETY-DAEHAN HWAHAK HOE JEE 2005. [DOI: 10.5012/jkcs.2005.49.6.617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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17
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Kim HS, Kim JH. Synthesis and Tautomerism of Novel Quinoxalines (Part I). JOURNAL OF THE KOREAN CHEMICAL SOCIETY-DAEHAN HWAHAK HOE JEE 2003. [DOI: 10.5012/jkcs.2003.47.3.241] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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18
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Abdulla HI, El-Bermani MF. Infrared studies of tautomerism in 2-hydroxypyridine 2-thiopyridine and 2-aminopyridine. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2001; 57:2659-2671. [PMID: 11765793 DOI: 10.1016/s1386-1425(01)00455-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The infrared spectra of 2-hydroxypyridine (2-OHP), 2-thiopyridine (2-SHP), and 2-aminopyridine (2-NH2P) have been recorded in the solid, liquid and vapor phases in the region 4000-200 cm(-1). To support the work, deuterated forms of these compounds in the functional groups XH and NH with (X=O, S, NH) were recorded for the solid and liquid phases. The results show existence of each compound as an equilibrium mixture of two tautomers in monomeric and cyclic dimeric forms in the solid, liquid and vapor phases. The monomers are predominant in the vapor phase. Enthalpy differences between the monomeric tautomers and activation energies for their inter-conversion were determined in each phase.
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Affiliation(s)
- H I Abdulla
- Department of Chemistry, College of Science, University of Baghdad, Iraq
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19
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Boga C, Bonamartini A, Forlani L, Modarelli V, Righi L, Sgarabotto P, Todesco P. Reactions of Hydroxypyridines with 1-Chloro-2,4,6-trinitrobenzene − Product Structure, Kinetics, and Tautomerism. European J Org Chem 2001. [DOI: 10.1002/1099-0690(200103)2001:6<1175::aid-ejoc1175>3.0.co;2-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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20
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Lomoth R, Naumov S, Brede O. Genuine Pyrimidine Radical Cations Generated by Radiation-Induced Electron Transfer to Butyl Chloride or Acetone Parent Ions. J Phys Chem A 1999. [DOI: 10.1021/jp9829804] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- R. Lomoth
- University of Leipzig, Interdisciplinary Group for Time-Resolved Spectroscopy and Institute of Surface Modification, Permoserstrasse 15, D-04303 Leipzig, Germany
| | - S. Naumov
- University of Leipzig, Interdisciplinary Group for Time-Resolved Spectroscopy and Institute of Surface Modification, Permoserstrasse 15, D-04303 Leipzig, Germany
| | - O. Brede
- University of Leipzig, Interdisciplinary Group for Time-Resolved Spectroscopy and Institute of Surface Modification, Permoserstrasse 15, D-04303 Leipzig, Germany
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