- Semi-empirical computation on mechanism of imidazolines and benzimidazoles synthesis and their QSAR studies
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A green, mild and anaerobic synthesis of imidazolines and benzimidazoles from aldehydes and diamines using I2/KI/K2CO3/H2O system has been investigated by semi-empirical methods. The observed efficient direction of the above synthesis has been modeled from a comparison of the energies of four possible transition states arising from mono and di additions of iodines in the configured molecules. In the reaction I1 B is the most favorable transition state [TS] which is shown to be 20 Kcal/mol by PM3 analyses. The resulting trends of relative transition states energies are in excellent agreement with the experimental observations. Also, the bond order, bond length, heat of formation is in good agreement to the formation of product B. In order to establish the suitable mechanism of the reaction a quantitative structure activity relationship analysis has been made using hydrophobicity as the molecular descriptor. In this analysis the values of refractivity, polarizability, hydration energy, electron affinity, ionization potential and dipole moment of the compounds have been correlated with their hydrophobicity which has been taken as the molecular property.
- Hazarika, Swapnali,Konwar, Dilip,Bora, Manas Jyoti
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p. 5073 - 5078
(2015/01/09)
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- Microwave mediated solvent free synthesis of 2-arylimidazolines from aldehydes using a solid base catalyst
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2-Aryl imidazolines have been synthesized in solvent free condition using a catalytic amount of solid base (500mg) and by exposure to microwave. Ketones are not affected under these reaction conditions. Reaction time is short, clean products have been obtained and recovery is simple. The yields of the products are good.
- Das, Pranab J.,Baruah, Akashi
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experimental part
p. 752 - 755
(2012/06/30)
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- T-shaped ionic liquid crystals based on the imidazolium motif: Exploring substitution of the C-2 imidazolium carbon atom
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In this contribution the first examples of so-called rigid-core, T-shaped imidazolium ionic liquid crystals, in which the C-2 atom of the imidazolium ring is substituted with an aryl moiety decorated with one or two alkoxy chains, are described. The length of the alkoxy chain(s) was varied from six to eighteen carbon atoms (n=6, 10, 14-18). Whereas the compounds with one long alkoxy chain display only smectic A phases, the salts containing two alkoxy chains exhibit smectic A, multicontinuous cubic, as well as hexagonal columnar phases, as evidenced by polarising optical microscopy, differential scanning calorimetry, and powder X-ray diffraction. Structural models are proposed for the self-assembly of the molecules within the mesophases. The imidazolium head groups and the iodide counterions were found to adopt a peculiar orientation in the central part of the columns of the hexagonal columnar phases. The enantiotropic cubic phase shown by the 1,3-dimethyl-2-[3,4-bis(pentadecyloxy) phenyl]imidazolium iodide salt has a multicontinuous Pmβar 3μ structure. To the best of our knowledge, this is the first example of a thermotropic cubic mesophase of this symmetry. Copyright
- Goossens, Karel,Wellens, Sil,Vana Hecke, Kristof,Van Meervelt, Luc,Cardinaels, Thomas,Binnemans, Koen
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supporting information; experimental part
p. 4291 - 4306
(2011/05/15)
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- Fragmentation of trifluoromethylated alkenes and acetylenes by N, N -binucleophiles. Synthesis of imidazolines or imidazolidines (Oxazolidines) controlled by substituent
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The reaction of β-halogeno-β-polyfluoromethylstyrenes with N,N- or N,O-binucleophiles leads to unexpected fragmentation products (imidazolines) or to heterocyclization giving CF3-substituted imidazolidines (N,N-) and oxazolidines (N,O-) depending on aryl substituent. The scope and the reaction mechanism are discussed.
- Nenajdenko, Valentine G.,Muzalevskiy, Vasiliy M.,Shastin, Aleksey V.,Balenkova, Elizabeth S.,Kondrashov, Evgeniy V.,Ushakov, Igor A.,Rulev, Alexander Yu.
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supporting information; scheme or table
p. 5679 - 5688
(2010/11/19)
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- Ultrasound promoted synthesis of 2-imidazolines in water: A greener approach toward monoamine oxidase inhibitors
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A series of sixteen 2-substituted-2-imidazolines (where the substituent R = Ph, Me-4-Ph; MeO-4-Ph; (MeO)2-3,4-Ph; (MeO)3-3,4,5-Ph; Ph-4-O-C(O)-Ph; Cl-4-Ph; Cl-2-Ph; Cl2-2,4-Ph; NO2-4-Ph; NO2-3-Ph; Naphth-2-yl; Fur-2-yl; Benzofur-2-yl; Pyridin-2-yl; Quinolin-2-yl) has been synthesized from the reaction of the substituted-aldehydes and ethylenediamine by ultrasound irradiation with NBS in an aqueous medium in high yields (80-99%). The 2-imidazoline ability to inhibit the activity of the A and B isoforms of monoamine oxidase (MAO) was investigated and some of them showed potent and selective MAO inhibitory activity especially for the MAO-B isoform and could become promising candidates for future development.
- Sant' Anna, Gabriela da S.,Machado, Pablo,Sauzem, Patricia D.,Rosa, Fernanda A.,Rubin, Maribel A.,Ferreira, Juliano,Bonacorso, Helio G.,Zanatta, Nilo,Martins, Marcos A.P.
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experimental part
p. 546 - 549
(2011/03/19)
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- An efficient and one-pot synthesis of imidazolines and benzimidazoles via anaerobic oxidation of carbon-nitrogen bonds in water
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The system, I2/KI/K2CO3/H2O, oxidizes carbon-nitrogen bonds for the synthesis of imidazolines and benzimidazoles from aldehydes and diamines under anaerobic conditions in water at 90°C with excellent yields. The process is green, mild and inexpensive.
- Gogoi, Pranjal,Konwar, Dilip
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- Synthesis of aldehydes from carboxylic acids via 2-imidazolines
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The use of readily available 2-substituted-2-imidazolines as precursors to 2-hydroxy aldehyde, unsaturated aldehyde and a variety of functionalized aldehydes is reported. It provides a novel method for the preparation of aldehydes from carboxylic acids via 2-substituted-2-imidazolines.
- Shi, Zhen,Gu, Huan
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p. 2701 - 2707
(2007/10/03)
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