- Synthesis, 1D and 2D NMR spectral assignments, and stereochemical studies of some 4,8,9,10-tetraaryl-1,3-diazaadamantan-6-one oximes
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A series of 4,8,9,10-tetraaryl-1,3-diazaadamantan-6-one oximes (4a-4e) have been synthesized. 1H and 13C NMR spectra of these oximes were recorded. Chemical shifts have been assigned and the stereochemistry of the compounds was established using 1D and 2D NMR spectral data. A detailed spectral investigation was carried out for one of the representative compounds (4a) with COSY, NOESY, HMQC, HMBC, DEPT-135, and N NMR spectral data. The NMR result clearly indicated the twin chair conformation of the two piperidine rings. The NMR results proved the axial orientation of two aryl groups (C4 and C10) in one piperidine ring and equatorial orientation of two aryl groups (C8 and C9) in another piperidine ring. The effect of allylic (A1,3) interaction between the oxime hydroxyl group and H-5e has been observed. Long-range coupling between H-10e and H-2 which are in ‘W’ arrangement is noted.
- Vengatesh,Sundaravadivelu
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p. 1929 - 1939
(2019/04/17)
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- Quantum chemical, experimental, theoretical spectral (FT-IR and NMR) studies and molecular docking investigation of 4,8,9,10-tetraaryl-1,3-diazaadamantan-6-ones
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Abstract: The compounds 4,8,9,10-tetraaryl-1,3-diazaadamantan-6-ones (a–e) were synthesized and characterized by FT-IR, 1H and 13C NMR spectra, and the spectral data have been theoretically analyzed by the DFT method. The electronic properties including a highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) and related parameters were calculated with B3LYP/6-311 G (d, p) basis set. The observed HOMO and LUMO mappings describe the different charge transfer possibilities within the molecule. Besides, the reactive properties of the molecules have been addressed based on the frontier molecular orbital analysis. The Molecular Electrostatic Potential and Fukui function analysis reveal the sites for electrophilic attack and nucleophilic reactions in the molecule. The intramolecular contacts have been interpreted using Natural Bond Orbital analysis and the thermodynamic properties also presented. The molecular docking study has been executed to study the binding interactions of the synthesized compounds with H1N1 swine virus-M2 proton channel and COX-2 protein. Graphical abstract: [Figure not available: see fulltext.].
- Vengatesh,Sundaravadivelu
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p. 4395 - 4415
(2019/05/07)
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- Facile denitrosation of Cyclic N-nitrosamines with hydrazoic acid
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A simple and facile method for the denitrosation of cyclic N-nitrosamines using HN3 (concentrated H2SO4+NaN3) is reported. In this method, limited usage of this reagent does not affect the carbonyl group.
- Ponnuswamy,Akila,Kiruthiga Devi
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supporting information
p. 2030 - 2034
(2015/08/18)
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- Chemistry of N-Nitroso Compounds. 1. Synthesis and Stereodynamics of N-Nitrosopiperidines and N-Nitrosopiperidin-4-ones
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The stereochemistry of a series of N-nitroso-r-2,c-6-diphenylpiperidin-4-ones (10-15) and N-nitroso-r-2,c-6-diphenylpiperidines (16-18) in solution has been investigated by 1H NMR, 13C NMR, and dynamic 1H NMR spectroscopic studies.Unlike the r-2,c-6-dialkyl-N-nitrosopiperidines, which have diaxial alkyl groups, these N-nitroso-r-2,c-6-diphenylpiperidines (16-18) and N-nitroso-r-2,c-6-diphenylpiperidin-4-ones (10-15) have diequatorial phenyl groups even though the nitroso group is coplanar to the dynamically averaged plane of the piperidine ring.The rotamer populations of the N-NO orientations in the nitrosamines were derived from continuous wave 1H NMR spectral data and are correlated with the steric bulk of the substituents present at the C-3 and C-5 positions.N-Nitroso-r-2,c-6-diphenylpiperidine-4-one (10) was found to have a higher rotational barrier than N-nitroso-r-2,c-6-diphenylpiperidine (16).We attribute this difference to a greater degree of coplanarity (C3-C2-N1-C6-C5) in 10 than in 16.The rotational barriers in 10 were found to decrease as the bulk of the substituents at C3 and C5 increased.The rotational barrier in N-nitroso-r-2,c-6-diphenylpiperidine (16) was found to be lower than the reported rotational barriers of N-nitroso-r-2,c-6-dimethylpiperidine and N-nitroso-2,2,6,6-tetramethylpiperidine.
- Ravindran, Thiruvenkadam,Jeyaraman, Ramasubbu,Murray, Robert W.,Singh, Megh
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p. 4833 - 4840
(2007/10/02)
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