Carboxylates ambient condition synthesis

Linking the ketone and carboxylic acid components together in an Ugi reaction facilitates the synthesis of pyrrolidinones amenable to library design. The three-component condensation of levulinic acid 30, an amine and isocyanide proceeds under microwave irradiation to give lactams 31 [65]. The optimum conditions were established by a design of experiments approach, varying the equivalents of amine, concentration, imine pre-formation time, microwave reaction time and reaction temperature, yielding lactams 31 at 100 °C in poor to excellent yield, after only 30 min compared to 48 h under ambient conditions (Scheme 11). 

Many synthetic methods have been developed to prepare pure rare earth-carboxylic acid complexes with high yields. Based on the starting materials, the methods can be put into two categories (i) rare earth oxides and (ii) rare earth salts. The synthesis can be done in aqueous solutions, organic media, or mixtures of the two, depending on the solubility and the nature of the ligands and the complexes, under ambient conditions, by hydro(solvo)thermal synthesis, or by gel synthesis. Under hydro(solvo)thermal conditions (in aqueous or non-aqueous media... 

Sun and coworkers have chemically attached poly(propionylethylenimine-co-ethyleni-mine), which is a widely used aminopolymer in peptide synthesis, to the acid-oxidation-induced carboxylic acid groups on CNTs via diimide-activated amidation with EDAC under ambient conditions. Various biomolecules, including DNA, PNA (peptide nucleic acid), and proteins, have also been successfully coupled to the acid-oxidized CNTs through the carboxylic acid functional linkers. 

Alternatively, hydrolysis of presumably not so soluble lanthanide carboxylate complexes may be possible by carrying out the hydrolysis under hydrothermal conditions. It appears that such conditions (high temperature and high pressure) are particularly conducive to the formation of polynuclear lanthanide complexes, often with unpredictable but nevertheless interesting structure. Under ambient pressure, analogous synthesis generally produces complexes with carboxylate coordination only and without any involvement of hydroxo groups. 

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