Overview of in situ and ex situ remediation technologies for PCB-contaminated soils and sediments and obstacles for full-scale application

Recent advances in the chemistry of α,β-unsaturated trifluoromethylketones

After an introduction reporting the properties and the applications of fluoropolymers and photopolymerizable derivatives, several basic information on photopolymerization processes are proposed. Then, this review deals with the state of the art on the synthesis of photopolymerizable fluoromonomers and oligomers: most classes of monomers are treated in separate sections (except fluorinated allyl ethers, which are used in copolymerization and are mentioned with the fluoro(meth)acrylics and macromonomers), eventually dividing the descriptions according to the monomer functionality. A short section further is devoted to fluorinated photoinitiators. After the synthesis, this review describes the main issues of the photopolymerization of fluorinated monomers together with the properties and performances obtained. A focus is given on the telechelic monomers and oligomers to insure a suitable crosslinking and on the copolymerization of fluorinated monomers for the surface modification of the obtained materials. Finally, properties and relevant applications (such as coatings and adhesives, optical fibers and flexible displays, polymer Exchange Membrane for Fuel Cell, microfluidic devices, high performance elastomers, and replica moldings) of these fluorinated photopolymerized materials will illustrate this review.

Fluorinated Oligomers and Polymers in Photopolymerization.

The preparation of N-methylpyrazoles is usually accomplished through reaction of a suitable 1,3-diketone with methylhydrazine in ethanol as the solvent. This strategy, however, leads to the formation of regioisomeric mixtures of N-methylpyrazoles, which sometimes are difficult to separate. We have determined that the use of fluorinated alcohols such as 2,2,2-trifluoroethanol (TFE) and 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as solvents dramatically increases the regioselectivity in the pyrazole formation, and we have used this modification in a straightforward synthesis of fluorinated analogs of Tebufenpyrad with acaricide activity.

Improved regioselectivity in pyrazole formation through the use of fluorinated alcohols as solvents: synthesis and biological activity of fluorinated tebufenpyrad analogs.

The sulfinatodehalogenation reaction represents one of the most important methodologies to incorporate fluorine into organic molecules. Using inexpensive sulfur-containing reactants such as Na2S2O4 under mild conditions, per- and polyfluoroalkyl halides (RFX, X = Br, I, CCl3) can be transformed smoothly into the corresponding sulfinate salts. This method is also used for the perfluoroalkylation of alkenes, dienes, alkynes and aromatics. Notably, after 1998, the sulfinatodehalogenation of perfluoroalkyl chlorides (RFCl) has been realized by using dimethylsulfoxide (DMSO) as a solvent instead of CH3CN/H2O in the Na2S2O4/NaHCO3 initiation system. Perfluoroalkyl chlorides, ethyl chlorofluoroacetates and chlorodifluoroacetates, and even nonfluorinated compounds, such as ethyl chloro- or dichloroacetates and chloroform, were either converted into the corresponding sulfinate salts or alkylated alkenes, alkynes and aromatics (including porphyrins). The sulfinatodehalogenation reaction has remarkable advantages. With the increasing demands to utilize the unique properties of fluorine and fluorinated functional groups in medicinal, agricultural and material sciences, we believe that there will continue to be useful developments in sulfinatodehalogenation chemistry and it will be applied more widely in the future.

Progress in fluoroalkylation of organic compounds via sulfinatodehalogenation initiation system

The data on the synthesis, structure and chemical transformations of 2-(het)arylhydrazono-1,3-dicarbonyl compounds is surveyed. The synthetic potential and possible applications of the title compounds are analyzed.

https://iopscience.iop.org/article/10.1070/RC2010v079n01ABEH004048/pdf

2-(Het)arylhydrazono-1,3-dicarbonyl compounds in organic synthesis

Synthesis and the reactions of trifluoromethylated 1,2,3-triketones 2-(het)arylhydrazones and 4,7-dihydroazolo[5,1-c]triazines

The review focuses on the methods of synthesis of 2-(1-alkoxyalkylidene)-1,3-dicarbonyl compounds and their chemical transformations. The reactivity of such compounds toward various mono- and dinucleophilic reagents is considered. The potential of these compounds for synthesis of different acyclic, carbo- and heterocyclic molecules is demonstrated. Special attention is paid to the practical use of 2-(1-alkoxyalkylidene)-1,3-dicarbonyl compounds and their derivatives, which are of interest in medicine and for design of new materials. The bibliography includes 226 references.

The use of 2-(1-alkoxyalkylidene)-1,3-dicarbonyl compounds in organic synthesis

Fluorinated 3-oxo esters react with aldehydes and 3-amino-1,2,4-triazoles and 5-aminotetrazoles to give, respectively, 7-alkyl(aryl)-6-alkoxycarbonyl-5-fluoroalkyl-1,2,4-triazolo[1,5-a]pyrimidines and -tetra-zolo[1,5-a]pyrimidines. The same heterocyclic products can be obtained by reaction of 2-benzylidene-2-fluoroacyl esters with the corresponding aminoazoles.

V. I. Saloutin

Papers

2-(Het)arylhydrazono-1,3-dicarbonyl compounds in organic synthesis

Synthesis and the reactions of trifluoromethylated 1,2,3-triketones 2-(het)arylhydrazones and 4,7-dihydroazolo[5,1-c]triazines

The use of 2-(1-alkoxyalkylidene)-1,3-dicarbonyl compounds in organic synthesis

Synthesis of 7-Alkyl(aryl)-6-alkoxycarbonyl-5-fluoroalkyl-1,2,4-tri(tetr)azolo[1,5-a]pyrimidines

Synthesis of fluorinated 2(3)-arylhydrazones of 1,2,3-tri(1,2,3,4-tetra)carbonyl compounds and their heterocyclization reactions