Use of a composition of an ionic nature as a substitution reagent, a composition constituting a fluorination reagent and a method using same

Abstract

The invention relates to processes for aromatic nucleophilic substitution by contacting a substrate of formula (III) Ar-Ξ  (III) where Ar is an aromatic group where the nucleus carrying the group Ξ is electron-poor, either because it contains at least one heteroatom in its ring or because the sum of the Hammett constants, σ p , of its substituents, apart from said Ξ, is at least 0.2, and Ξ is a leaving group, with a composition containing at least one ionic compound whose cation is of general formula G: (R 10 )(R 9 )N—[C(R 8 )═C(R 6 )] ν —C(R 5 )═N + (R 1 )(R 2 )  (G) wherein: ν is an integer from 0 to 4, inclusive; R 1 , R 2 , R 5 , R 6 and R 8 , which are identical or different, are a hydrogen or a hydrocarbon group; and R 9 and R 10 , which are identical or different, are a hydrocarbon group; or one or two of the substituents R 1 , R 2 , R 5 , R 8 , R 9 , and R 10 are connected to other remaining substituent(s) to form one or two or more rings.

1 . A process for carrying out a nucleophilic substitution on an aromatic substrate, comprising the step of:
 contacting a substrate of general formula (III):
   Ar-Ξ  (III) 
 wherein Ar is an aromatic group where the nucleus carrying the group Ξ is electron-poor, either because it contains at least one heteroatom in its ring or because the sum of the Hammett constants, σ p , of its substituents, apart from said Ξ, is at least 0.2, and, 
 wherein Ξ is a leaving group, 
   with a composition comprising at least one ionic compound whose cation is of general formula G:
   (R 10 )(R 9 )N—[C(R 8 )═C(R 6 )] ν —C(R 5 )═N + (R 1 )(R 2 )  (G) 
 wherein: 
 ν is an integer from 0 to 4, inclusive; 
 R 1 , R 2 , R 5 , R 6  and R 8 , which are identical or different, are a hydrogen or a hydrocarbon group; and 
 R 9  and R 10 , which are identical or different, are a hydrocarbon group; 
 or one or two of the substituents R 1 , R 2 , R 5 , R 8 , R 9 , and R 10  are connected to other remaining substituent(s) to form one or two or more rings. 
   
   
   
       2 . The process of  claim 1 , wherein R 1 , R 2 , R 5 , R 6  and R 8  are each a hydrogen or an alkyl group having not more than 4 carbon atoms. 
   
   
       3 . The process of  claim 1 , wherein R 9  and R 10  are each an alkyl group having not more than 4 carbon atoms. 
   
   
       4 . The process of  claim 1 , wherein the cation is of general formula G′: 
     
       
         
         
             
             
         
       
     
     wherein:
 R1 and R6, which are identical or different, are a hydrocarbon group, and, 
 R5′ represents a hydrogen, a hydrocarbon group or a group of formula: 
 
     
       
         
         
             
             
         
       
       where R 9  and R 10 , which are identical or different, are a hydrocarbon group. 
     
   
   
       5 . The process of  claim 1 , wherein the cation has the formula: 
     
       
         
         
             
             
         
       
       wherein R 9  and R 10  are alkyl groups having not more than 4 carbon atoms. 
     
   
   
       6 . The process of  claim 1 , wherein the cation has the formula: 
     
       
         
         
             
             
         
       
       wherein R 1 , R 5 , and R 6  are each independently hydrogen or alkyl groups having not more than 4 carbon atoms. 
     
   
   
       7 . The process of  claim 6 , wherein R 5  is a hydrogen and R 1  and R 6  are alkyl groups having not more than 4 carbon atoms. 
   
   
       8 . The process of  claim 7 , wherein R 1  is a methyl group. 
   
   
       9 . The process of  claim 7 , wherein R 6  is a methyl group and R 1  is an ethyl or a butyl group. 
   
   
       10 . The process of  claim 1 , wherein Ar comprises at least one leaving group other than Ξ. 
   
   
       11 . The process of  claim 1 , wherein the sum of the σ p  (Hammett constants) of the substituents Ar, apart from Ξ, is not more than 1. 
   
   
       12 . The process of  claim 1 , wherein Ar is such that the aromatic nucleus carrying Ξ is a 6-membered nucleus whose electron-withdrawing groups are groups which withdraw electrons by inductive and not mesomeric effect. 
   
   
       13 . The process of  claim 1 , wherein Ar is such that the aromatic nucleus carrying Ξ is a 6-membered nucleus whose electron-withdrawing groups are halogens. 
   
   
       14 . The process of  claim 1 , wherein Ar is such that the aromatic nucleus carrying Ξ is a 6-membered nucleus of which the electron-withdrawing group or at least one electron-withdrawing group is positioned meta to Ξ. 
   
   
       15 . The process of  claim 1 , wherein Ξ is a pseudohalogen, a chlorine or a bromine. 
   
   
       16 . The process of  claims 1 , wherein the at least one ionic compound comprises a fluoride ion as the anion. 
   
   
       17 . The process of  claim 1 , wherein the composition comprises as a co-anion an anion selected from halides and mixtures thereof. 
   
   
       18 . The process of  claim 1 , further comprising an anionic nucleophile for which the pKa of the associated acid is not more than 5. 
   
   
       19 . The process of  claim 1 , wherein the composition comprises fluoride ions. 
   
   
       20 . The process of  claim 1  wherein the sum of the bromide ions and the chloride ions is at least equal to ½ the amount of cation of formula G (expressed as equivalents). 
   
   
       21 . The process of  claim 1 , further comprising water, wherein the ratio, by mass, between the water and the salt whose cation corresponds to the formula G is not more than 200 ppm. 
   
   
       22 . The process of  claim 1 , wherein the composition comprises, apart from the substrate, in a liquid phase for successive or simultaneous addition:
 a) a ionic compound of which the cation is of general formula G, as defined in  claim 1 ;   b) a co-anion;   c) a nucleophilic substituent, optionally in salt form;   d) further components;   wherein, when (d) comprises an optional polar solvent, the latter is present in an amount such that the ratio by mass between the sum of the polar solvents and the sum of the salts of said compound of formula G, [S.P.]/(a+b), is not more than 1, and in that the sum of (a)+(b)+(c)+(d) represents 100% of said liquid phase.   
   
   
       23 . The process of  claim 22 , excluding substrate, having a ratio by mass between component (d) and components (a)+(b)+(c) being not more than 1. 
   
   
       24 . The process of  claim 22 , having, when the nucleophile is ionic, a molar ratio between component (c) and component (a) greater than 0.01. 
   
   
       25 . The process of  claim 22 , having, when the nucleophile is ionic, at least part of the co-anion formed from said nucleophile. 
   
   
       26 . The process of  claim 22 , having, when the nucleophile is ionic, a molar ratio (or equivalents ratio when the components are polyfunctional) between component (c) and component (a) greater than 0.5. 
   
   
       27 . The process of  claim 22 , further comprises a solid phase. 
   
   
       28 . The process of  claim 27 , wherein said solid phase comprises at least one salt formed from a mineral cation and the anion corresponding to said nucleophile or from the leaving group of said nucleophilic substitution. 
   
   
       29 . The process of  claim 22 , having said nucleophilic substituent present in the liquid phase in the form of a salt with a mineral cation and a molar ratio (or equivalents ratio) between said dissolved mineral cation and component (a) of at least 1/100. 
   
   
       30 . The process of  claim 22 , wherein the nucleophilic substituent is a fluoride ion. 
   
   
       31 . The process of  claim 1 , wherein the cation of general formula G is butylmethyllimidazolium. 
   
   
       32 . The process of  claim 1 , wherein the cation of general formula G is ethylmethylimidazolium. 
   
   
       33 . The process of  claim 1 , wherein the substrate is para-chloronitrobenzene. 
   
   
       34 . The process of  claim 1 , wherein the substrate is trichloronitrobenzene.