Two novel binuclear sulfonic-functionalized ionic liquids: Influence of anion and carbon-spacer on catalytic efficiency for one-pot synthesis of bis(indolyl)methanes

Construction of Bis‐Indole Derivatives Using α‐Amylase Enzyme: Application in the Gram‐Scale Synthesis of Bis‐Indole Containing Bioactive Molecules

“…Next, we presented a plausible mechanism for this transformation as depicted in Scheme 2. [37] In the first step, enzyme activates to the carbonyl group of benzaldehyde (2 a), afterwards the attack of indole molecules (1 a) taken place to provide the intermediate (A) which is also a rate determining step as reported by Kumar and co-workers. [38] Further, the removal of water leads to azafulven intermediate (C) which is attacked by the second molecule of indole to yields the final product (3 a).…”

Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles

“…In 2018, Khaligh and co-workers synthesized two new binuclear sulfonic-functionalized ionic liquids (TSIL) [1,1′-butylenebis(3-sulfo-3 H -imidazol-1-ium) chloride – BBSI-Cl and 1,1′-butylenebis(3-sulfo-3 H -imidazol-1-ium) hydrogen sulfate – BBSI-HSO 4 ] with chloride and hydrogen sulfate as the counter anions ( Scheme 51 ) [ 160 ]. The physical properties of the new TSILs were determined and their dual solvent–catalytic activity was investigated for the synthesis of the symmetrical BIMs under mild conditions ( Scheme 52 ) [ 160 ].…”

“…In 2018, Khaligh and co-workers synthesized two new binuclear sulfonic-functionalized ionic liquids (TSIL) [1,1′-butylenebis(3-sulfo-3 H -imidazol-1-ium) chloride – BBSI-Cl and 1,1′-butylenebis(3-sulfo-3 H -imidazol-1-ium) hydrogen sulfate – BBSI-HSO 4 ] with chloride and hydrogen sulfate as the counter anions ( Scheme 51 ) [ 160 ]. The physical properties of the new TSILs were determined and their dual solvent–catalytic activity was investigated for the synthesis of the symmetrical BIMs under mild conditions ( Scheme 52 ) [ 160 ]. The current protocol has benefits, such as simple and sustainable experimental procedures, good isolated yields of the desired products, short reaction times, satisfactory recyclability and chemoselectivity of the employed ionic liquids ( Scheme 53 ) [ 160 ].…”

4-(Dimethylamino)pyridinium chlorosulfonate: A new ionic liquid exhibiting chlorosulfonic acid action as monoprotic Brönsted acid and no sulfonating reagent

“…In extending our previous works on synthesis and characterization of the molten salts and ionic liquids containing -SO 3 H moiety and chlorosulfonate anion [18][19][20][21], herein, the action of chlorosulfonic acid (CSA) as a sulfonating agent or a monoprotic inorganic acid in reaction with 4-dimethylaminopyridine (DMAP), an Nheteroaromatic organic base, in CH 2 Cl 2 was investigated. A new ionic liquid with melting points 98-99 °C was obtained [22,23].…”