A General and Efficient Method for the Preparation of β‐Enamino Ketones and Esters Catalyzed by Indium Tribromide

Abstract

A variety of b-enamino ketones and esters have been synthesized in high to exellent yields by reacting b-dicarbonyl compounds with amines in the presence of a catalytic amount of indium tribromide. The reaction proceeds smoothly at room temperature in a short reaction time under solvent-free conditions.

Backbone-Substituted β-Ketoimines and Ketoiminate Clusters: Transoid Li2O2 Squares and D2-Symmetric Li4O4 Cubanes. Synthesis, Crystallography and DFT Calculations

“…Elemental analyses were obtained using an Elementar Vario Micro Cube (Langenselbold, Germany). The ketoimines 1a,b were synthesized by the literature methods [38].…”

“…The ketoimines 1c,d were prepared by the InBr 3 -catalysed condensation of 3-methyl-2,4-pentandione with the corresponding anilines MesNH 2 or DippNH 2 [38] and have been fully characterised in the solid and in solution; previous reports of these ligands do not seem to have provided full details. The spectroscopic properties resemble those of the previously reported 1a,b [36].…”

Ultrasound assisted synthesis of enaminones using Nickel oxide

“…Condensation of carbonyl compounds and amines mediated by acid catalysts is a simple methodology for synthesis of enamino esters. Diversified acid catalysts such as metal triflates 4 , perchlorates 5 , InBr 6 , CoCl 2 7 , silica supported mineral acid 8 , BF 3 *Et 2 O 9 , silver nanoparticles 10 , copper nanoparticles 11 , gold salts 12 and Zn(OAc) 2 13 have been used in the synthesis of β-enaminones and enamino esters. The above catalysts are either expensive or moisture sensitive or nonrecyclable or require harsh reaction conditions.…”

Amberlyst-15®: An Efficient, Cost-Effective and Recyclable Hetero Geneous Solid Acid Catalyst for the Synthesis of β-Enaminones and β- Enamino Esters

“…Among them, the most simple and straightforward conventional method is the azeotropic removal of water by refluxing an amine and 1,3-diketone in aromatic solvents [4]. Subsequently, a variety of activators such as InBr 3 [5], Zn(ClO 4 ) 2 [6], I 2 [7], p-TSA [8], H 2 SO 4 [9], NaAuCl 4 [10] [18], ionic liquid [19], ammonium carbamate [20] and solid supported reagents under solvent-free conditions have been used to accomplish this reaction. However, many of these methods suffer from drawbacks, such as drastic reaction conditions, tedious work up procedures and unsatis factory yields, which limit their use.…”