- Diethylamine-based ionic liquids: quantum chemical calculations and experiment
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The structural and energetic characteristics of the compounds formed by the reaction of diethylamine (DEA) with protic acids (sulfuric (H2SO4), methanesulfonic (MsOH), trifluoromethanesulfonic (TfOH), and para-toluenesulfonic (TsOH)) were examined using quantum chemical computations (B3LYP-GD3/6-31++G(d,p)). The strength of the hydrogen bonds in the ion pairs formed was quantitatively estimated by the QTAIM theory and NBO analysis. The results of the quantum chemical computations and the obtained thermal (phase transition and decomposition temperatures) and physicochemical (viscosity and conductivity) characteristics indicate that the reactions of DEA with the acids afford salts. The salts with the melting points higher than 100 °C are formed in the case of DEA/OTf(OTs), while protic ionic liquids are produced in the case of DEA/OMs(HSO4).
- Shmukler,Fedorova,Gruzdev,Fadeeva, Yu. A.,Safonova
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p. 2009 - 2019
(2019/12/23)
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- Multicomponent green synthesis, spectroscopic and structural investigation of multi-substituted imidazoles. Part 1
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Ten 1,2,4,5-tetra-substituted imidazole derivatives have been synthesized with a 2-hydroxyethy substituent at the 1-nitrogen atom and potentially electron releasing hydroxy-, methoxy-, dimethylamino- or nitro substituents in various positions on the benzene ring located on the 2-carbon atom. The prototypical derivative with an unsubstituted phenyl ring at the 2-position is also reported. The compounds are obtained in excellent yields (average 86 %) via a four-component cyclocondensation reaction of benzil, ethanolamine, and the appropriate aromatic carbaldehyde together with ammonium acetate. The reaction uses a novel ionic liquid catalyst, DEAHS (diethyl ammonium hydrogen sulfate), under solventfree conditions and a green synthetic protocol. The key advantages of this process are high yield, shorter reaction times and ease of work-up. Fürthermore, the products can be purified by a non-chromatographic method and the catalyst is re-usable. All of these newly synthesized compounds have been characterized from spectral data; the X-ray structures of three representative molecules are also detailed.
- Mohamed, Shaaban K.,Simpson, Jim,Marzouk, Adel A.,Talybov, Avtandil H.,Abdelhamid, Antar A.,Abdullayev, Yusif A.,Abbasov, Vagif M.
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p. 809 - 817
(2016/02/18)
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- [HSO4]-catalyzed eco-friendly and expeditious synthesis of thiazolidine and oxazolidine derivatives
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The present study reports a facile and green approach for the synthesis of thiazolidine/oxazolidine derivatives 4(a-u) in excellent yields (92-98%) with high purity. The protocol involves a one-pot three-component reaction of substituted 1,3-diketones 1(a-g), cyanates 2(a-c) and ethylchloroacetate (3) in ionic liquid [Et3NH][HSO4] under solvent-free conditions. The notable feature of this pathway is that the ionic liquid possesses both catalytic as well as medium engineering capability in this protocol. Use of [Et3NH][HSO4] as a catalyst and an environmentally benign solvent eliminates the need for a volatile organic solvent and additional catalyst. This ionic liquid is air and water stable and easy to prepare from cheap amine and acid. The present synthetic route is a green protocol offering several advantages, such as excellent yield of products, mild reaction conditions, minimizing chemical waste, shorter reaction time, simple operational procedure, easy preparation of the catalyst and its recyclability up to five cycles without any noticeable loss in catalytic activity. The protocol is applicable to a broad substrate scope. The optimization of conditions carried out in the present study revealed that 20 mol% of ionic liquid catalyst under solvent-free conditions at 120 °C are the best reaction parameters for the synthesis of thiazolidine/oxazolidine derivatives in excellent yields. This journal is
- Malla, Ali Mohammed,Parveen, Mehtab,Ahmad, Faheem,Azaz, Shaista,Alam, Mahboob
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p. 19552 - 19569
(2015/06/01)
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