Jagir S. Sandhu

Recent advances in ionic liquids: green unconventional solvents of this century: part II

Abstract The present overview describes ionic liquids as alternate, attractive solvents of today and tomorrow in organic synthesis. Since this subject is too wide and developments have been too fast, only a recent account is presented on indispensable carbon-carbon bond forming named reactions such as Knoevenagel, Michael Aldol, Biginelli Reaction, and so on, which has never been done before exclusively.

A Facile dehydration and beckmann rearrangement of oximes with aluminium iodide

Abstract Aluminium iodide has been developed as an efficient reagent for the conversion of aldoxims to nitriles and the Beckmann rearrangement of ketoximes to anilides.

Efficient, Solvent-Free, Microwave-Enhanced Condensation of 5,5-Dimethyl-1,3-cyclohexanedione with Aldehydes and Imines Using LiBr as Inexpensive, Mild Catalyst

Efficient, solvent-free, microwave-enhanced condensation of 5,5-dimethyl-1,3-cyclohexanedione with aldehydes using LiBr as catalyst affords xanthenediones. Imines gave only bis-5,5-dimethyl-1,3-cyclohexanediones at high power; a slightly longer period gave xanthenediones. In both types of reactions, the products are obtained in very good to excellent yields. The present protocol is inexpensive and ecofriendly.

RuCl3 · xH2O: A New Efficient Catalyst for Facile Preparation of 1,1‐Diacetates from Aldehydes

Abstract An efficient, facile preparation of aldehyde 1,1‐diacetates (acylals) in excellent yields catalyzed by RuCl3 · xH2O is described. Ketones do not react under these conditions.

New Strategy for the Oxidation of Hantzsch 1,4‐Dihydropyridines and Dihydropyrido[2,3‐d]pyrimidines Catalyzed by DMSO under Aerobic Conditions

Abstract A novel metal‐salt‐oxidant‐free, efficient, and economical method for the oxidation of Hantzsch 1,4‐dihydropyridines that uses aerial oxygen and solvent‐grade dimethylsulfoxide is described. Also, the synthesis of pyrido[2,3‐d]pyrimidines is achieved from in situ oxidation of dihydropyrido[2,3‐d]pyrimidines that arise from the reaction of 6‐aminouracils and cyano olefins in dimethylsulfoxide.

New Efficient Protocol for the Production of Hantzsch 1,4-Dihydropyridines Using RuCl3

Abstract Hantzsch 1,4-dihydropyridines are synthesized in a few minutes and in good to excellent yields from aldehydes, 1,3-dicarbonyl compounds, and ammonium acetate. The reaction is performed in solvent-free conditions, and 5 mol% of RuCl3 is enough for this protocol.

Ultrasound-assisted synthesis of 2,4-thiazolidinedione and rhodanine derivatives catalyzed by task-specific ionic liquid: [TMG][Lac]

Background Synthesized arylidene derivatives of rhodanine and 2,4-thiazolidiendione have potent pharmacological activities, and these are also key substrates for the preparation of clinically used antidiabetics. Findings Some 1,1,3,3-tetramethylguanidine-based task-specific ionic liquids (TSILs) 1a-1e were prepared and employed to the catalyzed solvent-free Knoevenagel condensation of 2,4-thiazolidinedione 3a and rhodanine 3b with a variety of aldehydes. Conclusions Best results were obtained with 1,1,3,3-tetramethylguanidine lactate ([TMG][Lac]) 1c. The TSIL used can be easily recovered and recycled, yielding products 4–5 in excellent yields under ultrasonic environment without the formation of any side products or toxic waste.

Multicomponent eco-friendly synthesis of 3,4-dihydropyrimidine-2-(1H)-ones using an organocatalyst Lactic acid

Abstract Biginelli compounds 3,4-dihydropyrimidine-2-(1H)-ones are synthesized in high yields via eco-friendly simple reaction procedure using Lactic acid: organocatalyst. The new method reported herein is green and is free of formation of any hazardous by products. The process has significant advantages over other reported methods.

Recent Pharmacological Developments on Rhodanines and 2,4-Thiazolidinediones

Thiazolidines are five-member heterocyclic having sulfur, nitrogen, and oxygen atoms in their ring structure and exhibiting potent as well as wide range of pharmacological activities. In this minireview, recent updates on synthesis and pharmacological evaluations of molecules based on 2,4-thiazolidine and rhodanine are discussed.

Bismuth(III) Chloride–Mediated, Efficient, Solvent-Free, MWI-Enhanced Doebner Condensation for the Synthesis of (E)-Cinnamic Acids

A bismuth(III) chloride–mediated green process for the production of (E)-cinnamic acid derivatives using microwave irradiation under solvent-free conditions is described. The (E)-cinnamic acids are obtained in excellent yields. This protocol is green because it employs an established environmentally benign procedure, microwave irradiation. Solvent vapor pollution is not there because it is solvent free, and bismuth(III) chloride is an established nontoxic catalyst.