Direct synthesis of dimethyl isosorbide (DMI) from d-sorbitol via dimethyl carbonate (DMC) chemistry is herein first reported. High yield of DMI was achieved using the nitrogen superbase 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as catalyst and performing the reaction in a stainless steel autoclave by increasing the temperature from 90 to 200 °C. In this procedure, DMC features its full capacity acting in the different steps of the process as carboxymethylating, leaving-group (cyclization), and methylating agent; DMC is also employed as the reaction media.
In this work we report on new examples of phenanthrolindiamides containing asymmetric centers in amide substituents. The synthesized ligands are expected to have complex thermodynamic behavior. Their structure was unambiguously...
Reprocessing
of spent nuclear fuel (SNF) is an important task in
a frame of ecology and rational use of natural resources. Uranium,
as the main component of SNF (>95%), can be recovered for further
use as fresh nuclear fuel. To minimize an amount of solid radioactive
waste generated during SNF reprocessing, new extractants are under
investigation. Diamides of 1,10-phenanthroline-2,9-dicarboxylic acid
are perspective tetradentate N-donor ligands that form strong complexes
with f-elements, which are soluble in polar organic
solvents. As an example of three ligands of this class, we conducted
a comparative study and showed how the substituent in the amide functional
group affects the extraction ability toward uranyl nitrate from nitric
acid media. We have performed a careful study (NMR, FT-IR, XRD, RMC-EXAFS)
of the structures of synthesized complexes of new ligands with uranyl
nitrate and used quantum mechanical calculations to explain the discovered
regularities through.
The Diels-Alder reaction of-fluoro-nitrostyrenes with some linear dienes was investigated. A number of monofluorinated [4+2]-cycloadducts was prepared in up to 90 % yield. The kinetics of [4+2]-cycloaddition to 2,3-dimethyl-1,3butadiene was studied in detail to reveal substituent effect and
The first examples of 1,10-phenanthroline-2,9-diamides bearing CF3-groups on the side amide substituents were synthesized. Due to stereoisomerism and amide rotation, such complexes have complicated behavior in solutions. Using advanced NMR techniques and X-ray analysis, their structures were completely elucidated. The possibility of the formation of complex compounds with lanthanoids nitrates was shown, and the constants of their stability are quantified. The results obtained are explained in terms of quantum-chemical calculations.
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