1734-79-8Relevant articles and documents
Efficient catalytic activity of transition metal ions in Vilsmeier-Haack reactions with acetophenones
Aneesa,Rajanna,Venkateswarlu,Reddy, K. Rajendar,Kumar, Y. Arun
, p. 721 - 733 (2013)
Vilsmeier-Haack (VH) formylation reactions with acetophenones are sluggish in acetonitrile medium even at elevated temperatures. However, millimolar concentrations of transition metal ions such as Cu(II), Ni(II), Co(II), and Cd(II) were found to exhibit efficient catalytic activity in Vilsmeier-Haack Reactions with acetophenones. Reactions are accelerated remarkably in the presence of transition metal ions. The VH reactions followed second order kinetics and afforded acetyl derivatives under kinetic conditions also irrespective of the nature of oxychloride (POCl3 or SOCl2) used for the preparation of VH reagent along with DMF. On the basis of UV-vis spectroscopic studies and kinetic observations, participation of a ternary precursor [M(II) S (VHR)] in the rate-limiting step has been proposed to explain the mechanism of the metal ion-catalyzed VH reaction.
Enantioselective Organocatalytic Synthesis of 1,2,3-Trisubstituted Cyclopentanes
?otolová, Martina,Kamlar, Martin,Reme?, Marek,Géant, Pierre-Yves,Císa?ová, Ivana,?tícha, Martin,Vesely, Jan
, p. 5080 - 5089 (2021/09/30)
An organocatalytic asymmetric domino Michael/α-alkylation reaction between enals and non-stabilized alkyl halides has been developed. Chiral secondary amine catalyzed cyclization reaction of 1-bromo-3-nitropropane with α,β-unsaturated aldehydes provides 1,2,3-trisubstituted cyclopentane carbaldehydes with high diastereo- (dr up to 8 : 1) and enantioselectivities (ee up to 96 %).
Boosting multiple photo-assisted and temperature controlled reactions with a single redox-switchable catalyst: Solvents as internal substrates and reducing agent
Bania, Kusum K.,Baruah, Manash J.,Bhattacharyya, Pradip K.,Das, Biraj,Karunakar, Galla V.,Roy, Subhasish,Saikia, Lakshi,Saikia, Pinku,Sharma, Mukesh
, p. 104 - 121 (2020/06/01)
An alternative and economically viable process for the synthesis of β-aryl enals, enones and the aryl amines has been developed by partial oxidation of ethanol, isopropanol and N, N-dimethyl formamide (DMF). The formation of β-aryl enals, enones and the aryl amines was catalyzed by a mixed metal oxides layer of cobalt and chromium supported on halloysite nanotubes, designated as CoCr2O4-HNT. The C[sbnd]C and C[sbnd]N bond formation reactions were found to be influenced by temperature and the nature of base. The condensation of aldehyde with in situ generated acetaldehyde by ethanol oxidation forming β-aryl enals occurred selectively at 120 °C. The partial oxidation of isopropanol to acetone and its condensation with aldehydes forming β-aryl enones occurred at room temperature. Increase in temperature caused the liberation of hydrogen gas from isopropanol and allowed the reversible reduction of aldehydes to alcohols. Increase in temperature in isopropanol and increase in base concentration in ethanol causes the selective reduction of aldehydes to alcohols. Besides being active for the Claisen-Schmidt type of reactions and the aryl halides amination process, the synthesized catalyst was also found to be highly active for the photocatalytic oxidation of benzyl alcohols in absence of any external oxidizing agent. The positive holes (h+) generated at the Co(II) site as evident from EPR analysis was considered to be responsible for high photocatalytic activity of the material reducing the recombination rate of holes and electrons (e?). Density Functional Theory calculations were performed to understand the mechanism of ethanol oxidation to acetaldehyde.
