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Ahmed BM, Mezei G. Selective, Ambient-Temperature C-4 Deuteration of Pyrazole Derivatives by D2O. J Org Chem 2018; 83:1649-1653. [DOI: 10.1021/acs.joc.7b03062] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Basil M. Ahmed
- Department of Chemistry, Western Michigan University, Kalamazoo, Michigan 49008, United States
| | - Gellert Mezei
- Department of Chemistry, Western Michigan University, Kalamazoo, Michigan 49008, United States
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Ahmed BM, Rudell NA, Soto I, Mezei G. Reaction of Amines with Aldehydes and Ketones Revisited: Access To a Class of Non-Scorpionate Tris(pyrazolyl)methane and Related Ligands. J Org Chem 2017; 82:10549-10562. [DOI: 10.1021/acs.joc.7b02070] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Basil M. Ahmed
- Department of Chemistry, Western Michigan University, Kalamazoo, Michigan 49008, United States
| | - Nicholas A. Rudell
- Department of Chemistry, Western Michigan University, Kalamazoo, Michigan 49008, United States
| | - Ixtlazihuatl Soto
- Department of Chemistry, Western Michigan University, Kalamazoo, Michigan 49008, United States
| | - Gellert Mezei
- Department of Chemistry, Western Michigan University, Kalamazoo, Michigan 49008, United States
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Zhang H, Wu W, Ahmed BM, Mezei G, Mo Y. Adjacent Lone Pair (ALP) Effect: A Computational Approach for Its Origin. Chemistry 2016; 22:7415-21. [PMID: 27139318 DOI: 10.1002/chem.201600509] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Indexed: 11/10/2022]
Abstract
The adjacent lone pair (ALP) effect is an experimental phenomenon in certain nitrogenous heterocyclic systems exhibiting the preference of the products with lone pairs separated over other isomers with lone pairs adjacent. A theoretical elucidation of the ALP effect requires the decomposition of intramolecular energy terms and the isolation of lone pair-lone pair interactions. Here we used the block-localized wavefunction (BLW) method within the ab initio valence bond (VB) theory to derive the strictly localized orbitals which are used to accommodate one-atom centered lone pairs and two-atom centered σ or π bonds. As such, interactions among electron pairs can be directly derived. Two-electron integrals between adjacent lone pairs do not support the view that the lone pair-lone pair repulsion is responsible for the ALP effect. Instead, the disabling of π conjugation greatly diminishes the ALP effect, indicating that the reduction of π conjugation in deprotonated forms with two σ lone pairs adjacent is one of the major causes for the ALP effect. Further electrostatic potential analysis and intramolecular energy decomposition confirm that the other key factor is the favorable electrostatic attraction within the isomers with lone pairs separated.
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Affiliation(s)
- Huaiyu Zhang
- The State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, Fujian Provincial Key Laboratory of Theoretical and Computational, Chemistry, and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian, 361005, P. R. China.,Department of Chemistry, Western Michigan University, Kalamazoo, MI, 49008, USA
| | - Wei Wu
- The State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, Fujian Provincial Key Laboratory of Theoretical and Computational, Chemistry, and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian, 361005, P. R. China.
| | - Basil M Ahmed
- Department of Chemistry, Western Michigan University, Kalamazoo, MI, 49008, USA
| | - Gellert Mezei
- Department of Chemistry, Western Michigan University, Kalamazoo, MI, 49008, USA
| | - Yirong Mo
- Department of Chemistry, Western Michigan University, Kalamazoo, MI, 49008, USA.
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Ahmed BM, Zhang H, Mo Y, Mezei G. Drastic Deprotonation Reactivity Difference of 3- and 5-Alkylpyrazole Isomers, Their I2-Catalyzed Thermal Isomerization, and Telescoping Synthesis of 3,5-Dialkylpyrazoles: The “Adjacent Lone Pair Effect” Demystified. J Org Chem 2016; 81:1718-22. [DOI: 10.1021/acs.joc.5b02746] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Basil M. Ahmed
- Department
of Chemistry, Western Michigan University, Kalamazoo, Michigan 49008-5413, United States
| | - Huaiyu Zhang
- Department
of Chemistry, Western Michigan University, Kalamazoo, Michigan 49008-5413, United States
| | - Yirong Mo
- Department
of Chemistry, Western Michigan University, Kalamazoo, Michigan 49008-5413, United States
| | - Gellert Mezei
- Department
of Chemistry, Western Michigan University, Kalamazoo, Michigan 49008-5413, United States
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Ahmed BM, Mezei G. Green protection of pyrazole, thermal isomerization and deprotection of tetrahydropyranylpyrazoles, and high-yield, one-pot synthesis of 3(5)-alkylpyrazoles. RSC Adv 2015. [DOI: 10.1039/c5ra00837a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
3(5)-Alkylpyrazoles are obtained in high yield from pyrazole by a one-pot procedure.
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Affiliation(s)
- Basil M. Ahmed
- Department of Chemistry
- Western Michigan University
- Kalamazoo
- USA
| | - Gellert Mezei
- Department of Chemistry
- Western Michigan University
- Kalamazoo
- USA
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Alabugin IV, Bresch S, dos Passos Gomes G. Orbital hybridization: a key electronic factor in control of structure and reactivity. J PHYS ORG CHEM 2014. [DOI: 10.1002/poc.3382] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Igor V. Alabugin
- Department of Chemistry and Biochemistry; Florida State University; Tallahassee FL 32306-4390 USA
| | - Stefan Bresch
- Department of Chemistry and Biochemistry; Florida State University; Tallahassee FL 32306-4390 USA
| | - Gabriel dos Passos Gomes
- Department of Chemistry and Biochemistry; Florida State University; Tallahassee FL 32306-4390 USA
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