New nucleophile-reactive sulfonated compounds for the (radio)labelling of (bio)molecules; precursors and conjugates thereof

Abstract

Nucleophile-reactive sulfonated compounds used as precursors to (radio)labelled (bio) molecules are produced by pre-introduction of a nucleophilic compound R* through an unusual nucleophile-induced ring-opening reaction of the sultone moiety of the precursor. The precursors and compounds conformconform.torespective formulae (Ip) and (I): Also disclosed are methods for producing these precursors and compounds, as well as for conjugation of these compounds with (bio)molecules, and to the drugs obtained by this method.

1 . A compound of formula (I) or a pharmaceutically acceptable salt thereof: 
       
         
           
           
               
               
           
         
       
       in which
 the R° bi-functional group is a spacer, preferably but not exclusively chosen among the following radicals: 
 
       
         
           
           
               
               
           
         
         the R 1  monovalent hydrocarbon group is an activating group of the oxygen atom of the ester function, R 1  preferably corresponding to a succinimidyl ester, a benzotriazole ester, a paranitrophenyl ester or a protecting labile, preferably acid-labile, function or hydrogen; 
         the R 2  monovalent group corresponds to a hydrogen, a metallic cation, an alkyl, a cyclo-alkyl, an aryl, an arylalkyl, an alkylaryl, an acyl, an alkenyl, an alkynyl radical or a combination of these radicals; hydrogen being preferred; 
         the R 2′  monovalent group, corresponds to an hydrogen or an alkyl, a cyclo-alkyl, an aryl, an arylalkyl, an alkylaryl, an acyl, an alkenyl, an alkynyl radical or a combination of these radicals; hydrogen being preferred; 
         the R 3  bi-functional group corresponds to a hydrocarbon moiety, preferably to a radical -(CR 4 R 5 ), n— , wherein R 4 , R 5  represents individually hydrogen or an alkyl, a cyclo-alkyl, an aryl, an arylalkyl, an alkylaryl, an acyl, an alkenyl, an alkynyl radical or a combination of these radicals; preferably hydrogen; n is preferably but not exclusively an integer between 1 and 3; 
         R* is a nucleophilic radical preferably containing at least one (radio)nuclide, preferably but not exclusively selected from the list fluorine-18, bromine-76, iodine-123, iodine-124, iodine-131 or characterized by NIR properties. 
       
     
     
         2 . The compound according to  claim 1 , wherein said compound conforms to formula (II): 
       
         
           
           
               
               
           
         
       
     
     
         3 . The compound according to  claim 1 , wherein said compound conforms to formula (III): 
       
         
           
           
               
               
           
         
       
       wherein
 R 4 ; R 5  preferably correspond to hydrogen. 
 
     
     
         4 . A precursor of a compound according to  claim 1 , the formula of which is: 
       
         
           
           
               
               
           
         
       
       wherein
 R 0 ; R 3  are as defined above; 
 R 10  is a protective monovalent group that avoid any side reaction on the carboxylic function and that make possible the reaction of the precursor (Ip) with a R* bearing nucleophilic compound and corresponds to an alkyl, a cyclo-alkyl or possibly a hydrogen or to R 1  as above defined, in case that R 1  permits the reaction of the precursor (Ip) with a R* bearing nucleophilic compound; 
 the functional units of formula COOR 10  and 
 
       
         
           
           
               
               
           
         
         being nucleophile-reactive, the nucleophilic reactivity of these functional units being different COOR 10 's nucleophilic reactivity being preferably less than the nucleophilic reactivity of 
       
       
         
           
           
               
               
           
         
       
     
     
         5 . A precursor of a compound according to  claim 4 , the formula (IIp) of which is: 
       
         
           
           
               
               
           
         
       
       wherein
 R 10  is a monovalent group as defined above; 
 the functional units of formula COOR 10  and 
 
       
         
           
           
               
               
           
         
         being nucleophile-reactive, the nucleophilic reactivity of these functional units being different, R 10 ′s nucleophilic reactivity being preferably less than the nucleophilic reactivity of 
       
       
         
           
           
               
               
           
         
       
     
     
         6 . A method for the synthesis of the precursor of formula (Ip) according to  claim 4 , comprising:
 i) implementing a structure, containing an ester and at least a second reactive function, of formula (IV)   
       
         
           
           
               
               
           
         
       
       wherein
 X is the second reactive function suitable to act as a leaving group during a nucleophilic substitution, X being preferably selected from the group consisting of an alkoxide function, a halogen, preferably selected from chlorine, bromine, iodine, a triflate, a tosylate and a mesylate; 
 the R 10 ′ monovalent group corresponds preferably but not exclusively to an alkyl or a cyclo-alkyl, one of the ester functions OR 10 ′ or a hydrogen; 
 ii) making formula (IV) react with: 
 at least one sultone—advantageously a butane sultone, propane sultone and/or an ethane sultone—, the sultone being preferably firstly methylated by means of a deprotonating agent, preferably n-butyl- lithium, and then acylated; 
 and with a protecting reagent capable of substituting the R 10 ′ function in formula (IV) by a protecting labile (preferably acid-labile) function R 10 ″. 
 
     
     
         7 . A method for obtaining a compound, the method comprisina the following stages:
 a) providing or synthesizing a precursor (Ip) according to  claim 4 ;   b) opening the sultone of said precursor (Ip) with a R* bearing nucleophilic radical leading to the formation of a sulphonate, preferably being carried out either in a polar protic typically as alcohols solvent or in the presence of a polar aprotic solvent which more preferably contains some water in an amount—given in an increasing order of preference and in % w/w—of less than or equal to 15; 10; 8; 6; 5; comprised between 1-4; 2-4; said solvent being a polar aprotic solvent or a protic solvent; said polar aprotic solvent being preferably selected from the group consisting of CH 3 CN, DMF, DMSO, THF, toluene, mixture CH 3 CN/DMF and. DMSO/water, said protic solvent used being preferably selected from the group consisting of water, MeOH, EtOH, i-PrOH, t-BuOH, Amyl alcohol or a mixture of them;   c) deprotecting the protected labile ester function;   d) activating the carboxylic function obtained as mentioned on stage c) by grafting of a R 1  monovalent group;   e) recovering the sulphonated nucleophilic-reactive compound obtained in stage d).   
     
     
         8 . The method according to  claim 7 , wherein the R* bearing reagent is adsorbed onto a elutable support and is afterwards eluted into a reactor wherein it reacts with the precursor (Ip), said elution being done by means of an eluent solution comprising at least one polar aprotic solvent and at least one phase transfer agent and/or a protic solvent and at least one transfer agent. 
     
     
         9 . The method according to  claim 8 , having at least one of the following features:
 (i) the polar aprotic solvent of the eluent solution is selected from the group consisting of CH 3 CN, DMF, DMSO, THF, toluene, mixture CH 3 CN/DMF or DMSO/water, preferably in an amount given in an increasing order of preference and in % w/w of less than or equal to 15; 10; 8; 6; 5; comprised between 1-4;2-4;   (ii) the protic solvent of the eluent solution is selected from the group consisting of water, MeOH, EtOH, i-PrOH, t-BuOH, Amyl alcohol and a mixtures thereof;   (iii)the phase transfer agent is selected among a quaternary amine, e.g. N(C 4 H 9 ) + B, or a compound of general formula Kriptand/MxBy, wherein Kriptand is a molecule suitable for a stable coordination of the metal M and wherein M is an alkaline metal, alkaline earth metal and in both cases B is a counter ion, for example, carbonate, bicarbonate, or oxalate, more preferably but not exclusively, said phase transfer agent is selected from the group consisting of: K222/Na 2 CO 3 ; K222/K 2 CO 3 ; K222/Cs 2 CO 3 ; K222/Rb 3 CO 3 ; TBAHCO 3 ; K222/K 2 C 2 C 4 ; K222/NaHCO 3 ; K222/KHCO 3 ; K222/RbHCO 3 ; K222/CaHCO 3 , where K222 corresponds to the kriptand 4,7,13,16,21,24-Hexaoxa-1,10-diazabicyclo [8.8.8]hexacosane and mixtures thereof; and,   (iv) the reaction between the R* bearing reagent and the precursor (Ip) is done in less than 15 minutes, at a temperature greater or equal to the room temperature, comprised between in an increasing order of preference: 30 and 150° C; 40 and 120° C.; 50 and 110° C.; 60 and 100° C; 80 and 100° C.   
     
     
         10 . A conjugate obtained from:
 at least one compound according to  claim 1 ;   and at least one molecule bearing at least one nucleophilic group.   
     
     
         11 . Drug or diagnosis product comprising at least one compound according to  claim 1 . 
     
     
         12 . Use of the compound according to  claim 1 , for labelling biomolecules with a radionuclide. 
     
     
         13 . Use of the compounds according to  claim 1 , for labelling biomolecules with a NIR agent. 
     
     
         14 . Use of the compounds according to  claim 1 , for imparting water-solubility to biomolecules bearing at least one nucleophilic group.