Design of Water Stable 1,3‐Dialkyl‐ 2‐Methyl Imidazolium Basic Ionic Liquids as Reusable Homogeneous Catalysts for Aza‐Michael Reaction in Neat Condition

Abstract

In this study, new members of mono cationic basic ionic liquids were synthesized as water stable viscous liquid consisting of 1, 3‐dialkyl‐2‐methyl imidazolium cation and acetate (or hydroxide) anion. Their structures were determined using 1H NMR, 13C NMR, FT‐IR and elemental analysis. Thermogravimetric analysis displayed maximum stabilities of six ionic liquids up to 260 °C. The UV‐Vis technique was employed to determine their comparable Hammett basicity order. Thermally stable five ionic liquids with less moisture content showed their catalytic activities by formation of 85–97% yields of β‐amino carbonyl compound for the model Aza‐Michael reaction of piperidine and acrylonitrile in neat condition with 2 and 5 mol % of catalysts for 5–15 min at room temperature. The optimized two catalysts [dbIm]OH and [daIm]OAc were reused efficiently with slight loss of activity for four cycles after the 1st run.

Structural Expansion of Chalcogenido Tetrelates in Ionic Liquids by Incorporation of Sulfido Antimonate Units

“…1‐Butyl‐2,3‐dimethylimidazolium tetrafluoroborate, (C 4 C 1 C 1 Im)[BF 4 ] (Sigma–Aldrich, 98 %), and 1‐butyl‐2,3‐dimethylimidazolium chloride, (C 4 C 1 C 1 Im)Cl (Sigma–Aldrich, ≥97 %), were vacuum‐dried for several days. (C 4 C 1 C 2 Im)Br was synthesized according to a slightly modified literature‐known synthesis procedure [53] . The starting materials K 4 [Ge 4 S 10 ] and K 4 [SnS 4 ]⋅4 H 2 O were prepared by solid state reaction of K 2 S, Ge or Sn, and S according to the literature [38] .…”

“…(C 4 C 1 C 2 Im)Br was synthesized according to as lightly modified literature-known synthesis procedure. [53] The starting materials K 4 [Ge 4 S 10 ]a nd K 4 [SnS 4 ]•4 H 2 Ow ere prepared by solid state reaction of K 2 S, Ge or Sn, and Sa ccording to the literature. [38] The raw product was purified by water-extraction.…”

Ionic Liquid‐Driven Formation of and Cation Exchange in Layered Sulfido Stannates – a CH2 Group Makes the Difference

“…As the metathesis caused the cations in the system to be replaced by the ionic liquid cations, an impact of the latter on the anionic substructure seems to be very likely. To explore this in more detail, we used a slightly different ionic liquid, (C 4 C 1 C 2 Im)Br, in which the CH 3 substituent in 3‐position of the imidazolium ring was replaced by a CH 2 CH 3 substituent [25,26] . The product, (C 4 C 1 C 2 Im) 2 [Sn 3 S 7 ] ( 1 b ), possesses the same nominal composition of the anionic substructure, yet with slight structural variations (see below).…”

Highly Soluble Supertetrahedra upon Selective Partial Butylation of Chalcogenido Metalate Clusters in Ionic Liquids

“…Thetarget compound 1 was obtained in two different salts with the sum formulas (C 4 C 1 C 4 Im) 4+x [Sn 10 O 4 S 16 (SBu) 4 ]Br x with x = 3( 1a)a nd x = 2( 1b). 1a was prepared by in situ butylation during the cluster formation reaction, which was carried out by treatment of K 4 [SnS 4 ]•4 H 2 O [23] in (C 4 C 1 C 4 Im)Br (A) [24] in the presence of 2,6-dimethylmorpholine (DMMP) at 180 8 8C. Crystals of 1b form upon dissolving crystals of compound 1a in CH 3 CN and subsequently removing the solvent under reduced pressure.W ea ttribute this finding to the high tendencyofthe ionic liquids to remain in solution, such that the crystals of 1a lose one formula unit of it under these conditions.S cheme 1s ummarizes the synthetic steps towards compounds 1a and 1b.…”