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Tukhvatshin RS, Kucherenko AS, Nelyubina YV, Zlotin SG. Conjugate Addition of Carbon Acids to β,γ-Unsaturated α-Keto Esters: Product Tautomerism and Applications for Asymmetric Synthesis of Benzo[ a]phenazin-5-ol Derivatives. J Org Chem 2019; 84:13824-13831. [PMID: 31566387 DOI: 10.1021/acs.joc.9b02021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A correlation between the equilibrium ratio of tautomeric products generated by the asymmetric Michael reactions of cyclic carbon acids with β,γ-unsaturated α-keto esters and the chemical shift of the α-proton in starting nucleophilic substrates was revealed which makes equilibration predictable. New tetrahydropyran-fused benzo[a]phenazins were enantioselectively (up to 99% ee) synthesized from β,γ-unsaturated α-keto esters and benzo[a]phenazin-5-ol, a powerful anti-cancer agent sAJM589. Facile recyclability of catalyst Ia in the catalytic reactions was demonstrated.
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Affiliation(s)
- Rinat S Tukhvatshin
- N. D. Zelinsky Institute of Organic Chemistry , Russian Academy of Sciences , 47, Leninsky Prospect , 119991 Moscow , Russian Federation.,A. N. Nesmeyanov Institute of Organoelement Compounds , Russian Academy of Sciences , 28, Vavilova Str , 119991 Moscow , Russian Federation
| | - Alexander S Kucherenko
- N. D. Zelinsky Institute of Organic Chemistry , Russian Academy of Sciences , 47, Leninsky Prospect , 119991 Moscow , Russian Federation
| | - Yulia V Nelyubina
- A. N. Nesmeyanov Institute of Organoelement Compounds , Russian Academy of Sciences , 28, Vavilova Str , 119991 Moscow , Russian Federation
| | - Sergei G Zlotin
- N. D. Zelinsky Institute of Organic Chemistry , Russian Academy of Sciences , 47, Leninsky Prospect , 119991 Moscow , Russian Federation
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52
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Mirzaei MS, Taherpour AA, Mirzaei S. Proton shuttle efficiency of bicarbonate: A theoretical study on tautomerization and CO2 hydration. Tetrahedron 2019. [DOI: 10.1016/j.tet.2019.130693] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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53
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Tomassetti M, Lupidi G, Piermattei P, Rossi FV, Lillini S, Bianchini G, Aramini A, Ciufolini MA, Marcantoni E. Catalyst-Free Synthesis of Polysubstituted 5-Acylamino-1,3-Thiazoles via Hantzsch Cyclization of α-Chloroglycinates. Molecules 2019; 24:molecules24213846. [PMID: 31731437 PMCID: PMC6864457 DOI: 10.3390/molecules24213846] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 10/21/2019] [Accepted: 10/21/2019] [Indexed: 11/17/2022] Open
Abstract
A catalyst-free heterocyclization reaction of α-chloroglycinates with thiobenzamides or thioureas leading to 2,4-disubstituted-5-acylamino-1,3-thiazoles has been developed. The methodology provides straightforward access to valuable building blocks for pharmaceutically relevant compounds.
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Affiliation(s)
- Mara Tomassetti
- Dompé Farmaceutici S.p.A., Via Pietro Castellino, Napoli 80131, Italy; (S.L.); (A.A.)
- Correspondence: (M.T.); (E.M.); Tel.: +39-(816)-132-220 (M.T.); Tel.: +39-(737)-402-255 (E.M.)
| | - Gabriele Lupidi
- School of Science and Technology, Chemistry Division, University of Camerino, Camerino 62032, Italy; (G.L.); (P.P.); (F.V.R.)
| | - Pamela Piermattei
- School of Science and Technology, Chemistry Division, University of Camerino, Camerino 62032, Italy; (G.L.); (P.P.); (F.V.R.)
| | - Federico V. Rossi
- School of Science and Technology, Chemistry Division, University of Camerino, Camerino 62032, Italy; (G.L.); (P.P.); (F.V.R.)
| | - Samuele Lillini
- Dompé Farmaceutici S.p.A., Via Pietro Castellino, Napoli 80131, Italy; (S.L.); (A.A.)
| | | | - Andrea Aramini
- Dompé Farmaceutici S.p.A., Via Pietro Castellino, Napoli 80131, Italy; (S.L.); (A.A.)
- Dompé Farmaceutici S.p.A., Via Campo di Pile, L’Aquila 67100, Italy;
| | - Marco A. Ciufolini
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada;
| | - Enrico Marcantoni
- School of Science and Technology, Chemistry Division, University of Camerino, Camerino 62032, Italy; (G.L.); (P.P.); (F.V.R.)
- Correspondence: (M.T.); (E.M.); Tel.: +39-(816)-132-220 (M.T.); Tel.: +39-(737)-402-255 (E.M.)
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54
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Supramolecular structures in oxovanadium(IV) compounds with pyrid-2-one and pyrid-4-one ligands. J Mol Struct 2019. [DOI: 10.1016/j.molstruc.2019.05.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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55
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DFT investigation on the intramolecular and intermolecular proton transfer processes in 2-aminobenzothiazole (ABT) in the gas phase and in different solvents. Struct Chem 2019. [DOI: 10.1007/s11224-019-01395-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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56
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Kral AE, Pflug NC, McFadden ME, LeFevre GH, Sivey JD, Cwiertny DM. Photochemical Transformations of Dichloroacetamide Safeners. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:6738-6746. [PMID: 31117539 DOI: 10.1021/acs.est.9b00861] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Dichloroacetamide safeners are commonly added to commercial chloroacetamide herbicide formulations and widely used worldwide, but their environmental fate has garnered little scrutiny as a result of their classification as "inert" ingredients. Here, we investigated the photolysis of dichloroacetamide safeners to better understand their persistence and the nature of their transformation products in surface waters. High-resolution mass spectrometry (HRMS) and nuclear magnetic resonance (NMR) spectroscopy were used to characterize photoproducts. Of the four commonly used dichloroacetamide safeners, only benoxacor undergoes direct photolysis under simulated natural sunlight ( t1/2 ∼ 10 min). Via a photoinitiated ring closure, benoxacor initially yields a monochlorinated intermediate that degrades over longer irradiation time scales to produce two fully dechlorinated diastereomers and a tautomer, which further photodegrade over several days to a structurally related aldehyde confirmed via NMR. Dichlormid, AD-67, and furilazole were more slowly degraded by indirect photolysis in the presence of the photosensitizers nitrate, nitrite, and humic acid. Reactive entities involved in these reactions are likely hydroxyl radical and singlet oxygen based on the use of selective quenchers. These safeners also directly photolyzed under higher energy ultraviolet (UV) light, suggesting their potential transformation in engineered systems using UV for disinfection. The finding that dichloroacetamide safeners can undergo photolysis in environmental systems over relevant time scales demonstrates the importance of evaluating the fate of this class of "inert" agrochemicals.
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Affiliation(s)
- Andrew E Kral
- Department of Civil & Environmental Engineering , University of Iowa , 4105 Seamans Center for the Engineering Arts and Sciences, Iowa City , Iowa 52242 , United States
| | - Nicholas C Pflug
- Department of Chemistry , University of Iowa , E331 Chemistry Building, Iowa City , Iowa 52242 , United States
| | - Monica E McFadden
- Department of Civil & Environmental Engineering , University of Iowa , 4105 Seamans Center for the Engineering Arts and Sciences, Iowa City , Iowa 52242 , United States
| | - Gregory H LeFevre
- Department of Civil & Environmental Engineering , University of Iowa , 4105 Seamans Center for the Engineering Arts and Sciences, Iowa City , Iowa 52242 , United States
- IIHR-Hydroscience & Engineering University of Iowa , 100 C. Maxwell Stanley Hydraulics Laboratory, Iowa City , Iowa 52242 , United States
| | - John D Sivey
- Department of Chemistry , Towson University , 543 Smith Hall, Towson , Maryland 21252 , United States
| | - David M Cwiertny
- Department of Civil & Environmental Engineering , University of Iowa , 4105 Seamans Center for the Engineering Arts and Sciences, Iowa City , Iowa 52242 , United States
- Department of Chemical & Biochemical Engineering , University of Iowa , 4133 Seamans Center for the Engineering Arts and Sciences, Iowa City Iowa 52242 , United States
- IIHR-Hydroscience & Engineering University of Iowa , 100 C. Maxwell Stanley Hydraulics Laboratory, Iowa City , Iowa 52242 , United States
- Center for Health Effects of Environmental Contamination , University of Iowa , 251 North Capitol Street , Chemistry Building - Room W195, Iowa City , Iowa 52242 , United States
- Public Policy Center , University of Iowa , 310 South Grand Avenue , 209 South Quadrangle, Iowa City , Iowa 52242 , United States
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57
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Antonov L. Tautomerism in Azo and Azomethyne Dyes: When and If Theory Meets Experiment. Molecules 2019; 24:molecules24122252. [PMID: 31212924 PMCID: PMC6631587 DOI: 10.3390/molecules24122252] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 06/13/2019] [Accepted: 06/14/2019] [Indexed: 12/15/2022] Open
Abstract
The performance of 26 hybrid density functionals was tested against a tautomeric dataset (TautData), containing experimental information for the keto-enol tautomeric equilibrium in 16 tautomeric azodyes and Schiff bases in cyclohexane, carbon tetrachloride and acetonitrile. The results have shown that MN12-SX, BHandH and M06-2X can be used to describe the tautomeric state of the core structures in the frame of ~0.5 kcal/mol error and correctly predict the tautomeric state in respect of dominating tautomeric form. Among them MN12-SX is the best performer, although it fails to describe the nonplanarity of some of the enol tautomers. The same experimental dataset was used to develop and test a special DFT functional (TautLYP) aimed at describing the tautomeric state in azo- and azomethyne compounds in solution when nonspecific solvents are used.
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Affiliation(s)
- Liudmil Antonov
- Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria.
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58
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Gülseven Sıdır Y, Berber H, Sıdır İ. The Dipole Moments and Solvatochromism of ((4-(Benzyloxy)benzylidene)amino)phenol Compounds as Solvatochromic Materials. J SOLUTION CHEM 2019. [DOI: 10.1007/s10953-019-00885-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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59
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Sahan F, Kose M, Hepokur C, Karakas D, Kurtoglu M. New azo‐azomethine‐based transition metal complexes: Synthesis, spectroscopy, solid‐state structure, density functional theory calculations and anticancer studies. Appl Organomet Chem 2019. [DOI: 10.1002/aoc.4954] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Fatma Sahan
- Department of ChemistryKahramanmaras Sutcu Imam University Kahramanmaras 46050 Turkey
| | - Muhammet Kose
- Department of ChemistryKahramanmaras Sutcu Imam University Kahramanmaras 46050 Turkey
| | - Ceylan Hepokur
- Faculty of Pharmacy, Department of Basic Pharmaceutical Sciences, Division of BiochemistryCumhuriyet University Sivas 58140 Turkey
| | - Duran Karakas
- Faculty of Science, Department of ChemistryCumhuriyet University Sivas 58140 Turkey
| | - Mukerrem Kurtoglu
- Department of ChemistryKahramanmaras Sutcu Imam University Kahramanmaras 46050 Turkey
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60
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One-pot pseudo three-component condensation reaction of arylglyoxal monohydrates with 1-ethyl-2-thioxodihydropyrimidine-4,6(1H,5H)-dione for the synthesis of new pyrano[2,3-d:6,5-d’]dipyrimidines as HIV integrase inhibitor-like frameworks using two different environmentally benign catalytic systems. JOURNAL OF THE IRANIAN CHEMICAL SOCIETY 2019. [DOI: 10.1007/s13738-019-01642-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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61
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Application of the Extended HOMED (Harmonic Oscillator Model of Aromaticity) Index to Simple and Tautomeric Five-Membered Heteroaromatic Cycles with C, N, O, P, and S Atoms. Symmetry (Basel) 2019. [DOI: 10.3390/sym11020146] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The geometry-based HOMA (Harmonic Oscillator Model of Aromaticity) descriptor, based on the reference compounds of different delocalizations of n- and π-electrons, can be applied to molecules possessing analogous bonds, e.g., only CC, only CN, only CO, etc. For compounds with different heteroatoms and a different number of CC, CX, XX, and XY bonds, its application leads to some discrepancies. For this reason, the structural descriptor was modified and the HOMED (Harmonic Oscillator Model of Electron Delocalization) index defined. In 2010, the HOMED index was parameterized for compounds with C, N and O atoms. For parametrization, the reference molecules of similar delocalizations of n- and π-electrons were employed. In this paper, the HOMED index was extended to compounds containing the CP, CS, NN, NP, PP, NO, NS, PO, and PS bonds. For geometrical optimization of all reference molecules and of all investigated heterocompounds, the same quantum–chemical method {B3LYP/6-311+G(d,p)} was used to eliminate errors of the HOMED estimation. For some tautomeric systems, the Gn methods were also employed to confirm tautomeric preferences. The extended HOMED index was applied to five-membered heterocycles, simple furan and thiophene, and their N and P derivatives as well as for tautomeric pyrrole and phosphole and their N and P derivatives. The effects of additional heteroatom(s) in the ring on the HOMED values for furan are parallel to those for thiophene. For pyrroles, aromaticity dictates the tautomeric preferences. An additional N atom in the ring only slightly affects the HOMED values for the favored and well delocalized NH tautomers. Significant changes take place for their rare CH forms. When intramolecular proton-transfer is considered for phosphole and its P derivatives, the PH tautomers seem to be favored only for 1,2,3-triphosphole/1,2,5-triphosphole and for 1,2,3,5-tetraphosphole. For other phospholes, the CH forms have smaller Gibbs energies than the PH isomers. For phosphazoles, the labile proton in the favored form is linked to the N atom. The PH forms have smaller HOMED indices than the NH tautomers but higher than the CH ones.
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62
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Raczyńska ED, Juras W. Effects of ionization and proton-transfer on bond length alternation in favored and rare isomers of isocytosine. COMPUT THEOR CHEM 2019. [DOI: 10.1016/j.comptc.2018.12.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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63
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Li MD, Wong NK, Xiao J, Zhu R, Wu L, Dai SY, Chen F, Huang G, Xu L, Bai X, Geraskina MR, Winter AH, Chen X, Liu Y, Fang W, Yang D, Phillips DL. Dynamics of Oxygen-Independent Photocleavage of Blebbistatin as a One-Photon Blue or Two-Photon Near-Infrared Light-Gated Hydroxyl Radical Photocage. J Am Chem Soc 2018; 140:15957-15968. [PMID: 30269478 DOI: 10.1021/jacs.8b10235] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Development of versatile, chemically tunable photocages for photoactivated chemotherapy (PACT) represents an excellent opportunity to address the technical drawbacks of conventional photodynamic therapy (PDT) whose oxygen-dependent nature renders it inadequate in certain therapy contexts such as hypoxic tumors. As an alternative to PDT, oxygen free mechanisms to generate cytotoxic reactive oxygen species (ROS) by visible light cleavable photocages are in demand. Here, we report the detailed mechanisms by which the small molecule blebbistatin acts as a one-photon blue light-gated or two-photon near-infrared light-gated photocage to directly release a hydroxyl radical (•OH) in the absence of oxygen. By using femtosecond transient absorption spectroscopy and chemoselective ROS fluorescent probes, we analyze the dynamics and fate of blebbistatin during photolysis under blue light. Water-dependent photochemistry reveals a critical process of water-assisted protonation and excited state intramolecular proton transfer (ESIPT) that drives the formation of short-lived intermediates, which surprisingly culminates in the release of •OH but not superoxide or singlet oxygen from blebbistatin. CASPT2//CASSCF calculations confirm that hydrogen bonding between water and blebbistatin underpins this process. We further determine that blue light enables blebbistatin to induce mitochondria-dependent apoptosis, an attribute conducive to PACT development. Our work demonstrates blebbistatin as a controllable photocage for •OH generation and provides insight into the potential development of novel PACT agents.
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Affiliation(s)
- Ming-De Li
- Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong Province , Shantou University , Shantou 515063 , China
| | - Nai-Kei Wong
- Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China.,State Key Discipline of Infectious Diseases , Shenzhen Third People's Hospital , Shenzhen 518112 , China
| | - Jia Xiao
- State Key Discipline of Infectious Diseases , Shenzhen Third People's Hospital , Shenzhen 518112 , China
| | - Ruixue Zhu
- Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China
| | - Liangliang Wu
- Department of Chemistry , Beijing Normal University , Xin-wai-da-jie 19 , Beijing 100875 , China
| | - Sheng-Yao Dai
- Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China
| | - Feng Chen
- State Key Discipline of Infectious Diseases , Shenzhen Third People's Hospital , Shenzhen 518112 , China
| | - Guanheng Huang
- Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong Province , Shantou University , Shantou 515063 , China
| | - Liang Xu
- Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong Province , Shantou University , Shantou 515063 , China
| | - Xiaoyu Bai
- Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China
| | - Margarita R Geraskina
- Department of Chemistry , Iowa State University , 2101d Hach Hall , Ames , Iowa 50011 , United States
| | - Arthur H Winter
- Department of Chemistry , Iowa State University , 2101d Hach Hall , Ames , Iowa 50011 , United States
| | - Xuebo Chen
- Department of Chemistry , Beijing Normal University , Xin-wai-da-jie 19 , Beijing 100875 , China
| | - Yingxia Liu
- State Key Discipline of Infectious Diseases , Shenzhen Third People's Hospital , Shenzhen 518112 , China
| | - Weihai Fang
- Department of Chemistry , Beijing Normal University , Xin-wai-da-jie 19 , Beijing 100875 , China
| | - Dan Yang
- Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China
| | - David Lee Phillips
- Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China
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64
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Raczyńska ED, Makowski M. Effects of Positive and Negative Ionization on Prototropy in Pyrimidine Bases: An Unusual Case of Isocytosine. J Phys Chem A 2018; 122:7863-7879. [PMID: 30192141 DOI: 10.1021/acs.jpca.8b07539] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Intramolecular proton-transfers (prototropic conversions) have been studied for the guanine building block isocytosine (iC), and effects of positive ionization, called one-electron oxidation (iC - e → iC+•), and negative ionization, called one-electron reduction (iC + e → iC-•), on tautomeric conversions when proceeding from neutral to ionized isocytosine have been discussed. Although radical cations and radical anions are very short-lived species, the ionization effects could be investigated by quantum-chemical methods. Such kind of studies gives some information about the labile protons and the most basic positions in the neutral and radical forms of the tautomeric system. For investigations, the complete isomeric mixture of isocytosine has been considered and calculations performed in two extreme environments, apolar {DFT(B3LYP)/6-311+G(d,p)} and polar {PCM(water)//DFT(B3LYP)/6-311+G(d,p)}. For selected isomers, the G4 theory has also been applied. There are no good relations for energetic parameters of neutral and ionized forms. Ionization energies depend on localization of labile protons. Tautomeric equilibria for neutral and ionized isocytosine, favored sites of protonation and deprotonation, and favored structures of protonated and deprotonated forms strongly depend on environment. Acidity of iC+• is close to that of the iC conjugate acid, and basicity of iC-• is close to that of the iC conjugate base. This increase of acid-base properties of charged radicals explains the proton-transfer in ionized pairs of nucleobases. When compared to other pyrimidine bases such as uracil (U) and cytosine (C), which exhibit analogous tautomeric equilibria between nine prototropic tautomers as isocytosine, the tautomeric preferences for iC, iC+•, iC-•, U, U+•, U-•, C, C+•, and C-• are completely different. The differences suggest that acid-base properties of functional groups, their stabilities, and ionization energies play a principal role in proton-transfers for pyrimidine bases and influence compositions of tautomeric mixtures.
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Affiliation(s)
- Ewa D Raczyńska
- Department of Chemistry , Warsaw University of Life Sciences (SGGW) , ul. Nowoursynowska 159c , 02-776 Warszawa , Poland
| | - Mariusz Makowski
- Faculty of Chemistry , University of Gdańsk , ul. Wita Stwosza 63 , 80-308 Gdańsk , Poland
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65
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Zhang H, Wu W, Mo Y. Tautomerism of protonated imidazoles: A perspective from ab initio valence bond theory. Tetrahedron 2018. [DOI: 10.1016/j.tet.2018.07.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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66
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Nguyen YH, Lampkin BJ, Venkatesh A, Ellern A, Rossini AJ, VanVeller B. Open-Resonance-Assisted Hydrogen Bonds and Competing Quasiaromaticity. J Org Chem 2018; 83:9850-9857. [PMID: 30024169 DOI: 10.1021/acs.joc.8b01331] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The delocalization of electron density upon tautomerization of a proton across a conjugated bridge can alter the strength of hydrogen bonds. This effect has been dubbed resonance-assisted hydrogen bonding (RAHB) and plays a major role in the energetics of the tautomeric equilibrium. The goal of this work was to investigate the role that π-delocalization plays in the stability of RAHBs by engaging other isomerization processes. Similarly, acid-base chemistry has received little experimental attention in studies of RAHB, and we address the role that acid-base effects play in the tautomeric equilibrium. We find that π-delocalization and the disruption of adjacent aromatic rings is the dominant effect in determining the stability of a RAHB.
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Affiliation(s)
- Yen H Nguyen
- Department of Chemistry , Iowa State University , Ame , Iowa 50011 , United States
| | - Bryan J Lampkin
- Department of Chemistry , Iowa State University , Ame , Iowa 50011 , United States
| | - Amrit Venkatesh
- Department of Chemistry , Iowa State University , Ame , Iowa 50011 , United States
| | - Arkady Ellern
- Department of Chemistry , Iowa State University , Ame , Iowa 50011 , United States
| | - Aaron J Rossini
- Department of Chemistry , Iowa State University , Ame , Iowa 50011 , United States
| | - Brett VanVeller
- Department of Chemistry , Iowa State University , Ame , Iowa 50011 , United States
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Mishra V, Thirupathi N. Critical Role of Anions in Platinum(II) Precursors upon the Structural Motifs of Six-Membered Cycloplatinated N, N', N″-Triarylguanidines. ACS OMEGA 2018; 3:6075-6090. [PMID: 31458795 PMCID: PMC6644913 DOI: 10.1021/acsomega.8b00782] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Accepted: 05/24/2018] [Indexed: 05/20/2023]
Abstract
The reactions of cis-[Pt(OAc)2(DMSO)2] with 2 equiv of sym N,N',N″-triarylguanidines, [ArN=C(NHAr)2], in toluene under reflux condition for 8 h afforded six-membered cycloplatinated guanidines, [Pt{κ2(C,N)}(OAc){κ1 N(ArN=C(NHAr)2)}] [sym = symmetrical; Ar = 2-MeC6H4 (1) and 2,4-Me2C6H3 (2)], in 82 and 84% yields, respectively. The salt metathesis reaction of 1 with 1 equiv of AgTFA in CH2Cl2 at room temperature (RT) afforded [Pt{κ2(C,N)}(TFA){κ1 N(ArN=C(NHAr)2)}] (3) in 94% yield. The reaction of cis-[Pt(TFA)2(DMSO)2] with 1 equiv of [ArN=C(NHAr)2] in toluene under reflux condition for 8 h afforded six-membered cycloplatinated guanidines, [Pt{κ2(C,N)}(TFA)(DMSO)] [Ar = 2-MeC6H4 (4), 4-MeC6H4 (5), 2,4-Me2C6H3 (6), and 2-(MeO)C6H4 (7)], in ≥73% yields. The reaction of trans-[PtCl2(PhCN)2] with 2 equiv of [ArN=C(NHAr)2] in toluene under reflux condition for 48 h afforded trans-[PtCl2{ArN=C(NHAr)2}2] [Ar = 2-MeC6H4 (8) and 2,4-Me2C6H3 (9)] in 90 and 45% yields, respectively. Complexes 8 and 9 were separately refluxed in MeOH for 8 h to afford six-membered cycloplatinated guanidines, [Pt{κ2(C,N)}(μ-Cl)]2 (10 and 11), in 93 and 96% yields, respectively, with concomitant formation of the respective guanidinium salts, [(ArNH)3C]Cl, as the byproduct. Platinacycle 10 was treated with 2 equiv of AgTFA in CH2Cl2 at RT to afford six-membered cycloplatinated guanidine, [Pt{κ2(C,N)}(μ-TFA)]2 (12), in 94% yield. The new compounds were characterized by analytical techniques and multinuclear NMR (1H, 13C, and 195Pt) spectroscopy, and further, molecular structures of 10 compounds were determined by single-crystal X-ray diffraction. The structural motif in 1·1/2CH2Cl2 and 3 is novel in that it contains a planar six-membered [Pt{κ2(C,N)}] unit and a nonplanar eight-membered [Pt{κ2(N,O)}] ring, wherein OAc and the guanidine ligands are linked through a N-H···O hydrogen bond. The six-membered cycloplatinated structural motifs present in 10/11·C7H8 and 12·CH2Cl2 are also unprecedented in the literature. The number and nature of solution species of new complexes were unambiguously investigated by detailed NMR studies. The critical role of anions in Pt(II) precursors upon the course of cycloplatination and thus the motifs in the products were addressed. Plausible mechanisms of cycloplatination reactions are discussed.
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68
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Yamaji M, Okamoto H. Photophysical features of naphthols having esters, formyl and acetyl groups and the difluoroboronated complex in solution and the solid state. J Photochem Photobiol A Chem 2018. [DOI: 10.1016/j.jphotochem.2018.04.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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69
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Soniya K, Chandra A. Free energy landscapes of prototropic tautomerism in pyridoxal 5′-phosphate schiff bases at the active site of an enzyme in aqueous medium. J Comput Chem 2018; 39:1629-1638. [DOI: 10.1002/jcc.25338] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 03/22/2018] [Accepted: 03/23/2018] [Indexed: 11/09/2022]
Affiliation(s)
- Kumari Soniya
- Department of Chemistry; Indian Institute of Technology; Kanpur 208016 India
| | - Amalendu Chandra
- Department of Chemistry; Indian Institute of Technology; Kanpur 208016 India
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70
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Feng GS, Chen MW, Shi L, Zhou YG. Facile Synthesis of Chiral Cyclic Ureas through Hydrogenation of 2-Hydroxypyrimidine/Pyrimidin-2(1H
)-one Tautomers. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201801485] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Guang-Shou Feng
- State Key Laboratory of Catalysis; Dalian Institute of Chemical Physics, Chinese Academy of Sciences; Dalian 116023 China
- University of Chinese Academy of Sciences; Beijing 100049 China
| | - Mu-Wang Chen
- State Key Laboratory of Catalysis; Dalian Institute of Chemical Physics, Chinese Academy of Sciences; Dalian 116023 China
| | - Lei Shi
- State Key Laboratory of Catalysis; Dalian Institute of Chemical Physics, Chinese Academy of Sciences; Dalian 116023 China
| | - Yong-Gui Zhou
- State Key Laboratory of Catalysis; Dalian Institute of Chemical Physics, Chinese Academy of Sciences; Dalian 116023 China
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71
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Feng GS, Chen MW, Shi L, Zhou YG. Facile Synthesis of Chiral Cyclic Ureas through Hydrogenation of 2-Hydroxypyrimidine/Pyrimidin-2(1H
)-one Tautomers. Angew Chem Int Ed Engl 2018; 57:5853-5857. [DOI: 10.1002/anie.201801485] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2018] [Revised: 03/14/2018] [Indexed: 12/18/2022]
Affiliation(s)
- Guang-Shou Feng
- State Key Laboratory of Catalysis; Dalian Institute of Chemical Physics, Chinese Academy of Sciences; Dalian 116023 China
- University of Chinese Academy of Sciences; Beijing 100049 China
| | - Mu-Wang Chen
- State Key Laboratory of Catalysis; Dalian Institute of Chemical Physics, Chinese Academy of Sciences; Dalian 116023 China
| | - Lei Shi
- State Key Laboratory of Catalysis; Dalian Institute of Chemical Physics, Chinese Academy of Sciences; Dalian 116023 China
| | - Yong-Gui Zhou
- State Key Laboratory of Catalysis; Dalian Institute of Chemical Physics, Chinese Academy of Sciences; Dalian 116023 China
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72
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Affiliation(s)
| | - Paul G. Seybold
- Department of Chemistry, Wright State University, Dayton, OH, USA
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73
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Li D, Han Y, Li H, Zhang P, Kang Q, Li Z, Shen D. The influence of isolated and penta-hydrated Zn 2+ on some of the intramolecular proton-transfer processes of thymine: a quantum chemical study. RSC Adv 2018; 8:11021-11026. [PMID: 35541537 PMCID: PMC9078977 DOI: 10.1039/c7ra13750h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Accepted: 02/27/2018] [Indexed: 02/02/2023] Open
Abstract
Zinc cation (Zn2+) plays an important role in the chemistry of DNA base pairs. In this work, the influence of isolated and penta-hydrated Zn2+ on some of the intramolecular proton-transfer processes of thymine (T) is investigated by the density functional theory method. It is shown that the calculated binding energies between Zn2+ and T are exothermic in vacuum. Compared to T, Zn2+ increases the stability of tautomer T' by 28.7 kcal mol-1, promoting the intramolecular proton transfer of T. But in a micro-water environment, the attachment processes of Zn2+ to T hydrates, penta-hydrated Zn2+ to T, and penta-hydrated Zn2+ to T hydrates lead to the rearrangement of molecules and the redistribution of charges. The conventional T is still the most stable form and the influence of Zn2+ is much reduced and the proton transfer is thermodynamically unfavored. The detailed characterization is helpful to understand the genotoxicity of zinc ions.
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Affiliation(s)
- Dejie Li
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, Shandong Normal University Jinan 250014 P. R. China
| | - Ying Han
- National Engineering Research Center for Colloidal Materials, School of Chemistry and Chemical Engineering, Shandong University Jinan 250100 P. R. China
| | - Huijuan Li
- College of Chemical and Environmental Engineering, Shandong University of Science and Technology Qingdao 266590 P. R. China
| | - Ping Zhang
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, Shandong Normal University Jinan 250014 P. R. China
| | - Qi Kang
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, Shandong Normal University Jinan 250014 P. R. China
| | - Zhihua Li
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, Shandong Normal University Jinan 250014 P. R. China
| | - Dazhong Shen
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, Shandong Normal University Jinan 250014 P. R. China
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74
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Latypov SK, Kondrashova SA, Galyametdinova IV, Semenov VE, Reznik VS. Hydrogen's isotopic exchange reaction in the C-methyl sides in the medicinal agent xymedon: NMR spectroscopy and ab initio calculations. J PHYS ORG CHEM 2018. [DOI: 10.1002/poc.3804] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Shamil K. Latypov
- A.E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Center; Russian Academy of Sciences; Kazan Russian Federation
| | - Svetlana A. Kondrashova
- A.E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Center; Russian Academy of Sciences; Kazan Russian Federation
- Kazan Federal University; Kazan Russian Federation
| | - Irina V. Galyametdinova
- A.E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Center; Russian Academy of Sciences; Kazan Russian Federation
| | - Vyacheslav E. Semenov
- A.E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Center; Russian Academy of Sciences; Kazan Russian Federation
| | - Vladimir S. Reznik
- A.E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Center; Russian Academy of Sciences; Kazan Russian Federation
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75
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Sahu S, Das M, Bharti AK, Krishnamoorthy G. Proton transfer triggered proton transfer: a self-assisted twin excited state intramolecular proton transfer. Phys Chem Chem Phys 2018; 20:27131-27139. [DOI: 10.1039/c8cp03835j] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The double excited state intramolecular proton transfer (ESIPT) of 3,5-bis(2-hydroxyphenyl)-1H-1,2,4-triazole (bis-HPTA) has been investigated and found to undergo a new type of proton transfer.
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Affiliation(s)
- Saugata Sahu
- Department of Chemistry
- Indian Institute of Technology Guwahati
- Guwahati
- India
| | - Minati Das
- Department of Chemistry
- Indian Institute of Technology Guwahati
- Guwahati
- India
| | | | - G. Krishnamoorthy
- Department of Chemistry
- Indian Institute of Technology Guwahati
- Guwahati
- India
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76
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77
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Sıdır YG, Pirbudak G, Berber H, Sıdır İ. Study on the electronic and photophysical properties of the substitute-((2-phenoxybenzylidene)amino)phenol derivatives: Synthesis, solvatochromism, electric dipole moments and DFT calculations. J Mol Liq 2017. [DOI: 10.1016/j.molliq.2017.07.070] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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78
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Raczyńska ED, Gal JF, Maria PC. The guanylated bioamine agmatine – A theoretical investigation of its structure and exceptional high basicity in the gas phase. COMPUT THEOR CHEM 2017. [DOI: 10.1016/j.comptc.2017.03.032] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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79
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Yu ZY, Chen MY, He JX, Tao DJ, Yuan JJ, Peng YY, Song ZB. Controllable Brønsted acid-promoted aerobic oxidation via solvation-induced proton transfer: Metal-free construction of quinazolinones and dihydroquinazolinones. MOLECULAR CATALYSIS 2017. [DOI: 10.1016/j.mcat.2017.03.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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80
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How OH and O– groups affect electronic structure of meta-substituted and para-substituted phenols and phenolates. Struct Chem 2017. [DOI: 10.1007/s11224-017-0965-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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81
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Carey TJ, Snyder JL, Miller EG, Sammakia T, Damrauer NH. Synthesis of Geometrically Well-Defined Covalent Acene Dimers for Mechanistic Exploration of Singlet Fission. J Org Chem 2017; 82:4866-4874. [DOI: 10.1021/acs.joc.7b00602] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Thomas J. Carey
- Department of Chemistry and
Biochemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Jamie L. Snyder
- Department of Chemistry and
Biochemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Ethan G. Miller
- Department of Chemistry and
Biochemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Tarek Sammakia
- Department of Chemistry and
Biochemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Niels H. Damrauer
- Department of Chemistry and
Biochemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
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82
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Natural polyprenylated benzophenone: keto-enol tautomerism from density functional calculations and the AIM theory. J Mol Model 2017; 23:140. [PMID: 28361442 DOI: 10.1007/s00894-017-3251-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 01/23/2017] [Indexed: 12/29/2022]
Abstract
The quantum theory of atoms in molecules (QTAIM) and density functional theory (DFT) calculations were employed to investigate the structure and tautomeric equilibrium of epiclusianone, a polyisoprenylated benzophenone with interesting biological activities. Two different exchange-correlation functionals were employed, namely ωB97x-D and M06-2x, including implicit solvent models (benzene and DMSO). Our results for the thermodynamic properties show that the isomer in which the H atom is bonded to the oxygen away from the benzene ring is the most stable tautomer form of the epiclusianone, thus confirming previous charge density analysis from X-ray diffraction data (Martins et al. J Braz Chem Soc 18(8):1515-1523, 22).
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83
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Fang G, Liu J, Fu J, Liu Q, Bi X. Silver-Catalyzed Cascade Reaction of β-Enaminones and Isocyanoacetates To Construct Functionalized Pyrroles. Org Lett 2017; 19:1346-1349. [DOI: 10.1021/acs.orglett.7b00201] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Guichun Fang
- Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis, Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | - Jianquan Liu
- Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis, Department of Chemistry, Northeast Normal University, Changchun 130024, China
- School
of Chemistry and Chemical Engineering, Jiangsu Key Laboratory of Green
Synthesis for Functional Materials, Jiangsu Normal University, Xuzhou 221116, China
| | - Junkai Fu
- Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis, Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | - Qun Liu
- Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis, Department of Chemistry, Northeast Normal University, Changchun 130024, China
| | - Xihe Bi
- Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis, Department of Chemistry, Northeast Normal University, Changchun 130024, China
- State
Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China
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84
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Proton tautomerism for strong polarization switching. Nat Commun 2017; 8:14426. [PMID: 28205550 PMCID: PMC5316872 DOI: 10.1038/ncomms14426] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 12/23/2016] [Indexed: 11/30/2022] Open
Abstract
Ferroelectrics based on proton tautomerism are promising in low-field and above-room-temperature operations. Here seven organic ferroelectric crystals are examined to search for efficient switching of strong spontaneous polarization on proton tautomerism. Solution-grown crystals exhibit strong pinning of ferroelectric domain walls, but excellent switching performance is awakened by depinning domain walls under thermal annealing and/or repetitive bipolar pulses with a high voltage. Compared with ferroelectric polymers such as polyvinylidefluoride, the optimized polarizations are comparable or stronger in magnitude whereas the coercive fields are two orders of magnitude weaker. The polarization of croconic acid, in particular, breaks its own record for organic systems in increasing from 21 to 30 μC cm−2 and now exceeds those of some commercial ferroelectric materials such as SrBi2Ta2O9 and BaTiO3. Optimization reduces the discrepancy of the spontaneous polarization with the results of the first-principles calculations to less than 15%. The cooperative roles of proton transfer and π-bond switching are discussed by employing the point-charge model and hydrogen-bond geometry. Ferroelectrics based on proton tautomerism are promising in low-field and above-roomtemperature operations. Here the authors establish a procedure to optimize spontaneous polarizations, finding that the polarization in croconic acid breaks its own record for organic systems.
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85
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86
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Genaev AM, Salnikov GE, Shernyukov AV, Zhu Z, Koltunov KY. Protonation Behavior of 1,1′-Bi-2-naphthol and Insights into Its Acid-Catalyzed Atropisomerization. Org Lett 2017; 19:532-535. [DOI: 10.1021/acs.orglett.6b03696] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Alexander M. Genaev
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Pr. Akademika Lavrentieva 9, Novosibirsk 630090, Russia
| | - George E. Salnikov
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Pr. Akademika Lavrentieva 9, Novosibirsk 630090, Russia
- Novosibirsk State University, Pirogova 2, Novosibirsk 630090, Russia
| | - Andrey V. Shernyukov
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Pr. Akademika Lavrentieva 9, Novosibirsk 630090, Russia
| | - Zhongwei Zhu
- Novosibirsk State University, Pirogova 2, Novosibirsk 630090, Russia
| | - Konstantin Yu. Koltunov
- Novosibirsk State University, Pirogova 2, Novosibirsk 630090, Russia
- Boreskov Institute of Catalysis, Pr. Akademika Lavrentieva 5, Novosibirsk 630090, Russia
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87
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Calzaferri G. Entropy in multiple equilibria, theory and applications. Phys Chem Chem Phys 2017; 19:10611-10621. [DOI: 10.1039/c7cp00584a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Entropy controls the dependence of the equilibrium constants in the synthesis of host–guest composites on the occupation rc for channels of different length.
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Affiliation(s)
- Gion Calzaferri
- Department of Chemistry and Biochemistry
- 3012 Bern
- Switzerland
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88
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Nishina N, Mutai T, Aihara JI. Excited-State Intramolecular Proton Transfer and Global Aromaticity. J Phys Chem A 2016; 121:151-161. [DOI: 10.1021/acs.jpca.6b11684] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Naoko Nishina
- Department of Chemistry,
Faculty of Science, Shizuoka University, Oya, Shizuoka 422-8529, Japan
| | - Toshiki Mutai
- Department
of Materials and Environmental Science, Institute of Industrial Science, The University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8505, Japan
| | - Jun-ichi Aihara
- Department of Chemistry,
Faculty of Science, Shizuoka University, Oya, Shizuoka 422-8529, Japan
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89
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90
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Raczyńska ED, Gal JF, Maria PC. Enhanced Basicity of Push-Pull Nitrogen Bases in the Gas Phase. Chem Rev 2016; 116:13454-13511. [PMID: 27739663 DOI: 10.1021/acs.chemrev.6b00224] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nitrogen bases containing one or more pushing amino-group(s) directly linked to a pulling cyano, imino, or phosphoimino group, as well as those in which the pushing and pulling moieties are separated by a conjugated spacer (C═X)n, where X is CH or N, display an exceptionally strong basicity. The n-π conjugation between the pushing and pulling groups in such systems lowers the basicity of the pushing amino-group(s) and increases the basicity of the pulling cyano, imino, or phosphoimino group. In the gas phase, most of the so-called push-pull nitrogen bases exhibit a very high basicity. This paper presents an analysis of the exceptional gas-phase basicity, mostly in terms of experimental data, in relation with structure and conjugation of various subfamilies of push-pull nitrogen bases: nitriles, azoles, azines, amidines, guanidines, vinamidines, biguanides, and phosphazenes. The strong basicity of biomolecules containing a push-pull nitrogen substructure, such as bioamines, amino acids, and peptides containing push-pull side chains, nucleobases, and their nucleosides and nucleotides, is also analyzed. Progress and perspectives of experimental determinations of GBs and PAs of highly basic compounds, termed as "superbases", are presented and benchmarked on the basis of theoretical calculations on existing or hypothetical molecules.
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Affiliation(s)
- Ewa D Raczyńska
- Department of Chemistry, Warsaw University of Life Sciences (SGGW) , ul. Nowoursynowska 159c, 02-776 Warszawa, Poland
| | - Jean-François Gal
- Institut de Chimie de Nice (ICN) - UMR CNRS 7272, University Nice Sophia Antipolis , Parc Valrose, 06108 Nice Cedex 2, France
| | - Pierre-Charles Maria
- Institut de Chimie de Nice (ICN) - UMR CNRS 7272, University Nice Sophia Antipolis , Parc Valrose, 06108 Nice Cedex 2, France
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91
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Pairas GN, Tsoungas PG. H-Bond: Τhe Chemistry-Biology H-Bridge. ChemistrySelect 2016; 1:4520-4532. [PMID: 32328512 PMCID: PMC7169486 DOI: 10.1002/slct.201600770] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Accepted: 07/29/2016] [Indexed: 12/19/2022]
Abstract
H-bonding, as a non covalent stabilizing interaction of diverse nature, has a central role in the structure, function and dynamics of chemical and biological processes, pivotal to molecular recognition and eventually to drug design. Types of conventional and non conventional (H-H, dihydrogen, H- π, CH- π, anti- , proton coordination and H-S) H-bonding interactions are discussed as well as features emerging from their interplay, such as cooperativity (σ- and π-) effects and allostery. Its utility in many applications is described. Catalysis, proton and electron transfer processes in various materials or supramolecular architectures of preorganized hosts for guest binding, are front-line technology. The H-bond-related concept of proton transfer (PT) addresses energy issues or deciphering the mechanism of many natural and synthetic processes. PT is also of paramount importance in the functions of cells and is assisted by large complex proteins embedded in membranes. Both intermolecular and intramolecular PT in H-bonded systems has received attention, theoretically and experimentally, using prototype molecules. It is found in rearrangement reactions, protein functions, and enzyme reactions or across proton channels and pumps. Investigations on the competition between intra- and intermolecular H bonding are discussed. Of particular interest is the H-bond furcation, a common phenomenon in protein-ligand binding. Multiple H-bonding (H-bond furcation) is observed in supramolecular structures.
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Affiliation(s)
- George N. Pairas
- Department of PharmacyLaboratory of Medicinal ChemistryUniversity of PatrasGR-265 04PatrasGreece
| | - Petros G. Tsoungas
- Laboratory of BiochemistryHellenic Pasteur Institute127 Vas. Sofias Ave.GR-115 21AthensGreece
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92
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Tautomerism in some pyrimidine nucleoside analogues used in the treatment of cancer: an ab initio study. Theor Chem Acc 2016. [DOI: 10.1007/s00214-016-1985-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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93
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Pyrka M, Maciejczyk M. Theoretical investigations of tautomeric equilibrium of 9-methyl-8-aza-iso-Guanine and its electrostatic properties. COMPUT THEOR CHEM 2016. [DOI: 10.1016/j.comptc.2016.07.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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94
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Safi ZS. A theoretical study on the structure of thiazolidine-2,4-dione and its 5-substituted derivatives in the gas phase. Implications for the thiazolidine-2,4-dione -water complex. ARAB J CHEM 2016. [DOI: 10.1016/j.arabjc.2015.03.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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95
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Mahmudov KT, Pombeiro AJL. Resonance-Assisted Hydrogen Bonding as a Driving Force in Synthesis and a Synthon in the Design of Materials. Chemistry 2016; 22:16356-16398. [PMID: 27492126 DOI: 10.1002/chem.201601766] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Indexed: 11/08/2022]
Abstract
Resonance-assisted hydrogen bonding (RAHB), a concept introduced by Gilli and co-workers in 1989, concerns a kind of intramolecular H-bonding strengthened by a conjugated π-system, usually in 6-, 8-, or 10-membered rings. This Review highlights the involvement of RAHB as a driving force in the synthesis of organic, coordination, and organometallic compounds, as a handy tool in the activation of covalent bonds, and in starting moieties for synthetic transformations. The unique roles of RAHB in molecular recognition and switches, E/Z isomeric resolution, racemization and epimerization of amino acids and chiral amino alcohols, solvatochromism, liquid-crystalline compounds, and in synthons for crystal engineering and polymer materials are also discussed. The Review can provide practical guidance for synthetic chemists that are interested in exploring and further developing RAHB-assisted synthesis and design of materials.
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Affiliation(s)
- Kamran T Mahmudov
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001, Lisboa, Portugal. .,Department of Chemistry, Baku State University, Z. Xalilov Str. 23, Az 1148, Baku, Azerbaijan.
| | - Armando J L Pombeiro
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001, Lisboa, Portugal.
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96
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The kinetics of water-assisted tautomeric 1,2-proton transfer in azoles: a computational approach. Struct Chem 2016. [DOI: 10.1007/s11224-016-0813-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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97
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Effects of ionization on stability of 1-methylcytosine - DFT and PCM studies. J Mol Model 2016; 22:146. [PMID: 27259531 PMCID: PMC4893064 DOI: 10.1007/s00894-016-3020-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 05/26/2016] [Indexed: 01/01/2023]
Abstract
Consequences of ionization were studied by quantum-chemical methods (DFT and PCM) for 1-methylcytosine (MC)—a model of the nucleobase cytosine (C) connected with sugar in DNA. For calculations, three prototropic tautomers (one amino and two imino forms) and two imino zwitterions were considered, including conformational or configurational isomerism of exo heterogroups. Ionization and interactions between neighboring groups affect intramolecular proton-transfers, geometric and thermodynamic parameters, and electron delocalization for individual isomers. We discovered that an imino isomer is present in the isomeric mixture in the highest amount for positively ionized MC. Its contribution in neutral and negatively ionized MC is considerably smaller. Acid-base parameters for selected radical ions were estimated in the gas phase and compared to those of neutral MC. Gas-phase acidity of radical cations is close to that of the conjugate acid of MC, and gas-phase basicity of radical anions is close to that of the conjugate base of MC. Various routes of amino-imino conversion between neutral and ionized isomers were considered. Energetic-barrier for intramolecular proton-transfer in MC is close to that in the parent system—formamidine.
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98
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Kumar D, Vemula SR, Cook GR. Merging C–H Bond Functionalization with Amide Alcoholysis: En Route to 2-Aminopyridines. ACS Catal 2016. [DOI: 10.1021/acscatal.6b00728] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Dinesh Kumar
- Department
of Chemistry and
Biochemistry, North Dakota State University, Fargo, North Dakota 58108-6050, United States
| | - Sandeep R. Vemula
- Department
of Chemistry and
Biochemistry, North Dakota State University, Fargo, North Dakota 58108-6050, United States
| | - Gregory R. Cook
- Department
of Chemistry and
Biochemistry, North Dakota State University, Fargo, North Dakota 58108-6050, United States
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99
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Borbulevych O, Martin RI, Tickle IJ, Westerhoff LM. XModeScore: a novel method for accurate protonation/tautomer-state determination using quantum-mechanically driven macromolecular X-ray crystallographic refinement. Acta Crystallogr D Struct Biol 2016; 72:586-98. [PMID: 27050137 PMCID: PMC4822566 DOI: 10.1107/s2059798316002837] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 02/17/2016] [Indexed: 11/16/2022] Open
Abstract
Gaining an understanding of the protein-ligand complex structure along with the proper protonation and explicit solvent effects can be important in obtaining meaningful results in structure-guided drug discovery and structure-based drug discovery. Unfortunately, protonation and tautomerism are difficult to establish with conventional methods because of difficulties in the experimental detection of H atoms owing to the well known limitations of X-ray crystallography. In the present work, it is demonstrated that semiempirical, quantum-mechanics-based macromolecular crystallographic refinement is sensitive to the choice of a protonation-state/tautomer form of ligands and residues, and can therefore be used to explore potential states. A novel scoring method, called XModeScore, is described which enumerates the possible protomeric/tautomeric modes, refines each mode against X-ray diffraction data with the semiempirical quantum-mechanics (PM6) Hamiltonian and scores each mode using a combination of energetic strain (or ligand strain) and rigorous statistical analysis of the difference electron-density distribution. It is shown that using XModeScore it is possible to consistently distinguish the correct bound protomeric/tautomeric modes based on routine X-ray data, even at lower resolutions of around 3 Å. These X-ray results are compared with the results obtained from much more expensive and laborious neutron diffraction studies for three different examples: tautomerism in the acetazolamide ligand of human carbonic anhydrase II (PDB entries 3hs4 and 4k0s), tautomerism in the 8HX ligand of urate oxidase (PDB entries 4n9s and 4n9m) and the protonation states of the catalytic aspartic acid found within the active site of an aspartic protease (PDB entry 2jjj). In each case, XModeScore applied to the X-ray diffraction data is able to determine the correct protonation state as defined by the neutron diffraction data. The impact of QM-based refinement versus conventional refinement on XModeScore is also discussed.
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Affiliation(s)
- Oleg Borbulevych
- QuantumBio Inc., 2790 West College Avenue, State College, PA 16801, USA
| | - Roger I. Martin
- QuantumBio Inc., 2790 West College Avenue, State College, PA 16801, USA
| | - Ian J. Tickle
- Astex Pharmaceuticals, 436 Science Park, Milton Road, Cambridge CB4 0QA, England
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100
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Głębocka A, Raczyńska ED, Chylewska A, Makowski M. Experimental (FT-IR) and theoretical (DFT) studies on prototropy and H-bond formation for pyrazine-2-amidoxime. J PHYS ORG CHEM 2016. [DOI: 10.1002/poc.3538] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Angelika Głębocka
- Laboratory of Intermolecular Interactions, Faculty of Chemistry; University of Gdańsk; Wita Stwosza 63 80-308 Gdańsk Poland
| | - Ewa D. Raczyńska
- Department of Chemistry; Warsaw University of Life Sciences; Nowoursynowska 159c 02-776 Warszawa Poland
| | - Agnieszka Chylewska
- Laboratory of Intermolecular Interactions, Faculty of Chemistry; University of Gdańsk; Wita Stwosza 63 80-308 Gdańsk Poland
| | - Mariusz Makowski
- Laboratory of Intermolecular Interactions, Faculty of Chemistry; University of Gdańsk; Wita Stwosza 63 80-308 Gdańsk Poland
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