A sequential acidic ionic liquid catalyzed one pot approach was conducted for preparation of 3‐substituted indoles starting from in situ generated chalcones involving Claisen‐Schmidt condensation of substituted aromatic aldehydes with acetophenone followed by Michael‐like addition of indoles to these chalcones under solvent‐free thermal reactions. For this purpose, some new and some reported Brönsted acidic ionic liquids, 2‐alkyl‐1, 3‐disulfoimidazolium carboxylate [RDSIM][X] (where R=Me & Et and X=CH3COO−, CCl3COO−, CF3COO−), were analyzed to compare their Brönsted acidic strength and thermal stabilities. From this investigation, 2‐methyl‐1, 3‐disulfoimidazolium trifluoroacetate [MDSIM][CF3COO] and 2‐ethyl‐1,3‐disulfoimidazolium trifluoroacetate [EDSIM][CF3COO] were determined as efficient ionic liquid catalysts for study of the two‐step one pot synthesis of 3‐substituted indoles.

A novel aza-Prins type cyclization reaction involving N-acyliminium ions and amides is reported for the synthesis of tetrahydropyrimido[2,1-a]isoindole-2,6-dione and 6,6a-dihydroisoindolo[2,1-a]quinazoline-5,11-dione derivatives in excellent yields. The strategy features inexpensive reagents, mild...

Intramolecular cyclization of enol ethers mediated by para-toluenesulfonic acid leads to substituted tetrahydropyrans in good to moderate yields. The reaction is diastereoselective.

quinolin-4-ones and dihydro-1H-benzo[b]azepines are efficiently synthesized from 2aminobenzonitriles and donor−acceptor cyclopropanes mediated by SnCl 4 in moderate to good yields. The reaction involves the initial ring opening of a cyclopropane ring due to activation by SnCl 4 followed by nucleophilic attack by amine to give an adduct, which after unprecedented rearrangement at two different reaction temperatures provides two nitrogen heterocyclic compounds. This methodology can be used for the synthesis of hexahydropyrrolo[3,2-c]quinolinone derivatives, the structure of which is found in biologically active molecules.