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Du P, Zhao J, Liu S, Yue Z. Insights into the nucleophilic substitution of pyridine at an unsaturated carbon center. RSC Adv 2021; 11:24238-24246. [PMID: 35479030 PMCID: PMC9036673 DOI: 10.1039/d1ra03019a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Accepted: 06/28/2021] [Indexed: 11/21/2022] Open
Abstract
Bimolecular nucleophilic substitution (SN2) is a fundamental reaction that has been widely studied. So far, the nucleophiles are mainly anionic species in SN2 reactions. In this study, we use density functional theory calculations to assess the mechanisms of substitution of carbonyl, imidoyl, and vinyl compounds with a neutral nucleophile, pyridine. Charge decomposition analysis is performed to explore the main components of the transition state's LUMO. For reactions of imidoyl or carbonyl compounds with pyridine or Cl−, the LUMOs of the transition states are composed of mixed orbitals originating from the nucleophile and the substrate. Considering the unique mixed nature of the orbitals, the reaction mode is termed SNm (m means mix). Moreover, the main components of the transition state's LUMO are pure σ*C–Cl MO in the reactions of H2C
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CHCl with pyridine or Cl−. Computations were also performed for RYCHX substrates with different X and Y groups (X= Cl−, Br−, or F−; Y = O, N, or C). The nucleophilic substitution of carbonyl, imidoyl, and vinyl carbon centers with pyridine or halides is investigated in this paper.![]()
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Affiliation(s)
- Pan Du
- School of Life Science and Chemistry, Jiangsu Second Normal University Nanjing 210013 China
| | - Jiyang Zhao
- School of Environmental Science, Nanjing Xiaozhuang University Nanjing 211171 China
| | - Shanshan Liu
- School of Environmental Science, Nanjing Xiaozhuang University Nanjing 211171 China
| | - Zhen Yue
- School of Environmental Science, Nanjing Xiaozhuang University Nanjing 211171 China
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Datta S, Limpanuparb T. Steric effects vs. electron delocalization: a new look into the stability of diastereomers, conformers and constitutional isomers. RSC Adv 2021; 11:20691-20700. [PMID: 35479364 PMCID: PMC9033979 DOI: 10.1039/d1ra02877d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 05/24/2021] [Indexed: 01/22/2023] Open
Abstract
A quantum chemical investigation of the stability of compounds with identical formulas was carried out on 23 classes of compounds made of C, N, P, O and S atoms as core structures and halogens H, F, Cl, Br and I as substituents. All possible structures were generated and investigated by quantum mechanical methods. The prevalence of a formula in which its Z configuration, gauche conformation or meta isomer is the most stable form is calculated and discussed. Quantitative and qualitative models to explain the stability of the 23 classes of halogenated compounds were also proposed. The prevalence of a chemical formula in which its Z configuration, gauche conformation or meta isomer is the most stable form is derived from over ten thousand chemical structures. The instance of steric prediction failure is surprisingly common.![]()
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Affiliation(s)
- Sopanant Datta
- Science Division, Mahidol University International College, Mahidol University Salaya Nakhon Pathom 73170 Thailand
| | - Taweetham Limpanuparb
- Science Division, Mahidol University International College, Mahidol University Salaya Nakhon Pathom 73170 Thailand
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Abstract
Afatinib is a 4-anilinoquinazoline tyrosine kinase inhibitor (TKI) in the form of a dimaleate salt which is indicated for the treatment of locally advanced or metastatic non-small cell lung cancer (NSCLC). The most scalable route for the synthesis of this drug was reported in two Boehringer Ingelheim patents, in which the title compound, 4,7-dichloro-6-nitroquinazoline (IV), is an important intermediate. Compound IV is also present in a number of synthetic pathways for various 4,7-disubstituted quinazoline derivatives displaying high therapeutic potential. However, no detailed characterization of this popular compound has been reported, possibly due to its high instability. In this paper, IV was prepared in an overall yield of 56.1% by a 3-step process (condensation, nitration, and chlorination) from 2-amino-4-chlorobenzoic acid (I). The target compound has been for the first time fully characterized by melting point, mass-spectrometry, FT-IR, 1H-NMR and 13C-NMR spectroscopies.
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de Castilho RB, Ramalho TC, Nunez CV, Coutinho LH, Santos ACF, Pilling S, Lago AF, Silva-Moraes MO, de Souza GGB. Single and double ionization of the camphor molecule excited around the C 1s edge. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2014; 28:1769-1776. [PMID: 24975258 DOI: 10.1002/rcm.6961] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 06/07/2014] [Accepted: 06/08/2014] [Indexed: 06/03/2023]
Abstract
RATIONALE An interesting class of volatile compounds, the monoterpenes, is present in some plants although their functions are not yet fully understood. We have studied the interaction of the camphor molecule with monochromatic high-energy photons (synchrotron radiation) using time-of-flight mass spectrometry and coincidence techniques. METHODS A commercial sample of S-camphor was admitted into the vacuum chamber, without purification, through an inlet system. Monochromatic light with energy around the C 1s edge was generated by the TGM beamline at the Brazilian Synchrotron Facility. A Wiley-McLaren mass spectrometer was used to characterize and detect the ions formed by the camphor photoionization. The data analysis was supported by energy calculations. RESULTS Although the fragmentation patterns were basically the same at 270 eV and 330 eV, it was observed that above the C 1s edge the contribution to the spectrum from lower mass/charge fragment ions increased, pointing to a higher degree of dissociation of the molecule. Projections of the PEPIPICO spectra demonstrated the existence of unstable doubly charged species. The Gibbs free energy was calculated using the Møller-Plesset perturbation theory (MP2) for the neutral, singly and doubly excited camphor molecule. CONCLUSIONS Our PEPIPICO spectrum clearly demonstrated the formation of doubly ionic dissociative species. From a slope analysis, we propose a secondary decay after a deferred charge separation mechanism in which, after a few steps, the camphor dication dissociates into C2 H3 (+) and C3 H5 (+) . This is the main relaxation route observed at 270 eV and 330 eV. The large energy difference between the mono and the dication (of the order of 258.2 kcal/mol) may explain the experimentally observed absence of stable dications in the spectra, because their formation is disadvantaged energetically.
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Affiliation(s)
- R B de Castilho
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal do Amazonas (UFAM), Campus Universitário, Coroado, 69077-000, Manaus, AM, Brazil
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5
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Lee I. Natural bond orbital analysis of the intrinsic reaction barriers in nucleophilic displacements. INT REV PHYS CHEM 2010. [DOI: 10.1080/0144235031000086058] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Ikchoon Lee
- a Department of Chemistry , Inha University , Inchon , 402-751 , South Korea
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Miyamoto K, Okubo T, Hirobe M, Kunishima M, Ochiai M. Effects of stereochemistry and β-substituents on the rates of vinylic SN2 reaction of hypervalent vinyl(phenyl)-λ3-iodanes with tetrabutylammonium halides. Tetrahedron 2010. [DOI: 10.1016/j.tet.2010.04.041] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Natural and H2-reduced limonite for organic oxidation by a Fenton-like system: Mechanism study via ESI-MS and theoretical calculations. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/j.molcata.2007.09.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Nucleophilic Substitution Reactions of α-Chloroacetanilides with Pyridines in Dimethyl Sulfoxide. B KOREAN CHEM SOC 2005. [DOI: 10.5012/bkcs.2005.26.5.776] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Kunsági-Máté S, Skoda-Földes R, Szepes L, Végh E, Kollár L. Unexpected reactivity difference between iodo-alkene moieties of steroids possessing remote lactame or cycloalkane structural units: a theoretical approach. ACTA ACUST UNITED AC 2004; 61:69-75. [PMID: 15560923 DOI: 10.1016/j.jbbm.2004.06.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2003] [Revised: 04/22/2004] [Accepted: 06/19/2004] [Indexed: 11/26/2022]
Abstract
The steroidal ring A possessing cyclohexane vs. delta-valerolactame structures shows a 'long-range effect' on the reactivity of the 'iodovinyl' functionality of the ring D. The strikingly different reactivity of 17-iodo-16-ene functionality of steroids is explained on the basis of the redistribution of kinetic energy of the system. The vibrational energy localized on the 'iodovinyl' moiety proved to be determinant in the CI bond-breaking process. The appearance of the lactame moiety in the ring A supports a redistribution of the kinetic energy on the molecule. As a result, a drastic decrease in C-I bond stretching has been obtained, which could diminish the C-I bond breaking, and therefore, results in decreased reactivity of the iodovinyl moiety in agreement with experimental findings.
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Affiliation(s)
- Sándor Kunsági-Máté
- Faculty of Sciences, Department of General and Physical Chemistry, University of Pécs, H-7624 Pécs, Ifjúság 6, Hungary.
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Oh HK, Kim IK, Lee HW, Lee I. Kinetics and Mechanism of the Addition of Benzylamines to Benzylidenediethylmalonates in Acetonitrile. J Org Chem 2004; 69:3806-10. [PMID: 15153013 DOI: 10.1021/jo034370s] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Kinetic studies of the benzylamine additions to benzylidenediethylmalonates (BDM: YC(6)H(4)CH[double bond]C(COOEt)(2)) in acetonitrile at 20.0 degrees C are reported. The rates in acetonitrile are consistent with that expected from the through-conjugative electron-accepting power of the activating groups, (COOEt)(2). The sign and magnitude of the cross-interaction constant, rho(XY) = -0.45, are in general agreement with those for the single-step amine additions to activated olefins. The kinetic isotope effects (k(H)/k(D) > 1.0) measured with deuterated benzylamines (XC(6)H(4)CH(2)ND(2)) increase with a stronger electron-acceptor substituent in benzylamines (partial differential sigma(X) > 0) and a stronger electron donor in the substrate (partial differential sigma(Y) < 0). These trends are the same as those found for benzylidene-1,3-indandiones but are exactly opposite to those for other activated olefin series, e.g., beta-nitrostyrene. It has been shown that the former series are thermodynamically controlled, whereas the latter are intrinsically controlled with a relatively strong transition state imbalance. The activation parameters, Delta H(++) and Delta S(++), also support our proposed transition state involving concurrent C(alpha)-N and C(beta)-H bond formation with a four-membered cyclic structure.
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Affiliation(s)
- Hyuck Keun Oh
- Department of Chemistry, Chonbuk National University, Chonju 560-756, Korea
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11
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Theoretical Studies on the Structure and Acidity of Meldrum's Acid and Related Compounds. B KOREAN CHEM SOC 2003. [DOI: 10.5012/bkcs.2003.24.8.1141] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Lee KS, Adhikary KK, Lee HW, Lee BS, Lee I. Nucleophilic substitution reactions of alpha-chloroacetanilides with benzylamines in dimethyl sulfoxide. Org Biomol Chem 2003; 1:1989-94. [PMID: 12945784 DOI: 10.1039/b300477e] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Kinetic studies of the reactions of alpha-chloroacetanilides (YC6H4NRC(=O)CH2Cl; R = H (5) and CH3 (6)) with benzylamines (NH2CH2C6H4X) were carried out in dimethyl sulfoxide at 55.0 degrees C. The Brønsted betaX values were in the range from 0.6 to 0.9 and cross-interaction constants phoXY were positive: phoXY = +0.21 and +0.18 for 5 and 6, respectively. The rates were faster with 6 than with 5 and inverse secondary kinetic isotope effects involving deuterated benzylamine (ND2CH2C6H4X) nucleophiles, kH/kD < 1.0, were obtained. Based on these and other results, a stepwise mechanism with rate-limiting expulsion of the chloride leaving group from a zwitterionic tetrahedral intermediate, T+/-, is proposed. In this mechanism, a prior carbonyl addition to T+/- is followed by a bridged type transition state to expel the chloride. An enolate-like transition state in which the developing negative charge on C(alpha) delocalizes toward the carbonyl group (nC-->pi*(C=O) interaction) is not feasible for the present series of reactions due to a stronger charge transfer involving the lone pair on the anilino nitrogen (nAN-->pi*(C=O) interaction).
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Affiliation(s)
- Ki Sun Lee
- Department of Chemistry, Inha University, Inchon 402-751, Korea
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13
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Theoretical Studies of the Gas-Phase Identity Nucleophilic Substitution Reactions of Cyclopentadienyl Halides. B KOREAN CHEM SOC 2003. [DOI: 10.5012/bkcs.2003.24.5.583] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Choi JY, Kim CK, Kim CK, Lee I. High Level ab Initio Study of Thermal 1,3-Sigmatropic Shift in CH2CHCH2X with X = BH2, NH2, and CH3. J Phys Chem A 2002. [DOI: 10.1021/jp025721u] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jun Yong Choi
- Department of Chemistry, Inha University, Inchon 402-751, Korea
| | - Chang Kon Kim
- Department of Chemistry, Inha University, Inchon 402-751, Korea
| | - Chan Kyung Kim
- Department of Chemistry, Inha University, Inchon 402-751, Korea
| | - Ikchoon Lee
- Department of Chemistry, Inha University, Inchon 402-751, Korea
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Kim CK, Li HG, Lee BS, Kim CK, Lee HW, Lee I. Gas-phase identity nucleophilic substitution reactions of cyclopropenyl halides. J Org Chem 2002; 67:1953-60. [PMID: 11895417 DOI: 10.1021/jo0164047] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The gas-phase identity nucleophilic substitution reactions of halide anions (X = F, Cl, and Br) with cyclopropenyl halides, X(-) + (CH)(3)X <= => X(CH)(3) + X(-), are investigated theoretically at four levels of theory, B3LYP/6-311+G**, MP2/6-311+G**, G2(+)MP2//MP2/6-311+G**, and G2(+)//MP2/6-311+G**. Four types of reaction paths, the sigma-attack S(N)2, pi-attack S(N)2'-syn, and S(N)2'-anti and sigmatropic 1,2-shift, are possible for all the halides. In the fluoride anion reactions, two types of stable adducts, syn- and anti-1,2-difluorocyclopropyl anions, can exist on the triple-well-type potential energy surface of the identity substitution reactions with rearrangement of double bond (C=C), S(N)2'-syn, and S(N)2'-anti processes. The TSs for the sigma-attack S(N)2 paths have "open" (loose) structures so that the ring positive charges are high rendering strong aromatic cyclopropenyl (delocalized) cation-like character. In contrast, in the pi-attack S(N)2' paths, a lone pair is formed at the unsubstituted carbon (C3), which stabilizes the 1,2-dihalocyclopropyl (delocalized) anion-like TS by two strong n(C)-sigma*(C-F) vicinal charge-transfer delocalization interactions. The barrier height increases in the order S(N)2'-anti < sigma-attack S(N)2 < S(N)2'-syn for X = Cl and Br, whereas for X = F the order is changed to S(N)2'-anti < S(N)2'-syn < sigma-attack S(N)2 due to the stable difluoro adduct formation. The sigmatropic 1,2-shift (circumambulatory) reactions have high activation barriers and cannot interfere with the substitution reactions.
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Affiliation(s)
- Chang Kon Kim
- Department of Chemistry, Inha University, Inchon 402-751, Korea
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Kinetics and Mechanism of the Addition of Benzylamines to Ethyl-α-cyanocinnamates in Acetonitrile. B KOREAN CHEM SOC 2002. [DOI: 10.5012/bkcs.2002.23.2.221] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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17
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Lee I, Hong SW, Koh HJ, Lee Y, Lee BS, Lee HW. Structure-reactivity relationships in the pyridinolysis of N-methyl-N-arylcarbamoyl chlorides in dimethyl sulfoxide. J Org Chem 2001; 66:8549-55. [PMID: 11735537 DOI: 10.1021/jo0108212] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Nucleophilic substitution reactions of N-methyl-N-arylcarbamoyl chlorides (YC(6)H(4)N(CH(3))COCl) with pyridines (XC(5)H(4)N) have been investigated in dimethyl sulfoxide at 45.0 degrees C. A striking trend in the selectivity parameters is that they are constant within experimental errors, rho(X) = -2.25 +/- 0.03, beta(X) = 0.42 +/- 0.01, and rho(Y) = 1.10 +/- 0.06, with changing reactivities of the electrophiles (deltasigma(Y)) and nucleophiles (deltasigma(X)), respectively, and this leads to a vanishingly small cross-interaction constant, rho(XY) approximately equals beta(XY) approximately equals 0. The rate data can be expressed in the Ritchie N(+) type equation. Based on this and other results, the mechanism of nucleophile (pyridine) addition to the resonance- stabilized carbocation is proposed. It has been shown from the definition of beta(XY) (and rho(XY)) together with the Marcus equation that the high intrinsic barrier, DeltaG(0), in the intrinsic-barrier controlled reaction series is a prerequisite for such reactions in which the cross-interaction vanishes and the N(+) relationship holds.
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Affiliation(s)
- I Lee
- Department of Chemistry, Inha University, Inchon, 402-751 Korea.
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