Methods for Preparing Internally Constrained Peptides and Peptidomimetics

Abstract

The present invention relates to a method for preparing a peptide having a stable, internally constrained alpha-helical, beta-sheet/beta-turn, 3 10 -helical, or pi-helical region and a method of stabilizing an alpha-helical, beta-sheet/beta-turn, 3 10 -helical, or pi-helical region within a peptide structure. The resulting peptides and methods of using them are also disclosed.

1 . A method of preparing a compound of Formula II: 
       
         
           
           
               
               
           
         
       
       wherein
 R is hydrogen, an amino acid side chain, an alkyl group, or an aryl group; 
 R 1  is an amino acid side chain, an alkyl group, or an aryl group; 
 R 2  is an amino acid, peptide, OR, CH 2 NH 2 , an alkyl group, an aryl group, or a group of Formula: 
 
       
         
           
           
               
               
           
         
         
           wherein R 7  is an amino acid, peptide, OR, CH 2 NH 2 , an alkyl group, or an aryl group; 
         
            is a single or double carbon-carbon bond;   is a single bond and 
         is cis or trans when   is a double bond; n is 1 or 2; and m is any number, said method comprising: 
         providing a compound of Formula III or a salt thereof: 
       
       
         
           
           
               
               
           
         
       
       wherein R 4  is a carboxyl protecting group and reacting said compound of Formula III or a salt thereof with a peptide coupling reagent of Formula III′: 
       
         
           
           
               
               
           
         
       
       under conditions effective to produce a compound of Formula II. 
     
     
         2 . The method according to  claim 1 , wherein said providing a compound of Formula III or salt thereof comprises:
 providing a compound of Formula IV:   
       
         
           
           
               
               
           
         
       
       and
 reacting said compound of Formula IV under conditions effective to produce a compound of Formula III or salt thereof. 
 
     
     
         3 . The method according to  claim 2 , wherein said providing a compound of Formula IV comprises:
 providing a compound of Formula V:   
       
         
           
           
               
               
           
         
       
       wherein R 3  is a carboxyl protecting group that is different from R 4  and R 5  is an amine protecting group and
 reacting said compound of Formula V under conditions effective to produce a compound of Formula IV. 
 
     
     
         4 . The method according to  claim 3 , wherein said providing a compound of Formula V comprises:
 providing a compound of Formula VI:   
       
         
           
           
               
               
           
         
         providing a compound of Formula VI′: 
       
       
         
           
           
               
               
           
         
         reacting said compound of Formula VI with said compound of Formula VI′ under conditions effective to produce a compound of Formula V. 
       
     
     
         5 . The method according to  claim 4 , wherein said providing a compound of Formula VI comprises:
 providing a compound of Formula VII:   
       
         
           
           
               
               
           
         
       
       wherein LG is a leaving group and
 reacting said compound of Formula VII with an amino acid protected at a carboxyl end of the amino acid under conditions effective to produce a compound of Formula VI. 
 
     
     
         6 . The method according to  claim 5 , wherein said providing a compound of Formula VII comprises:
 providing a compound of Formula VIII:   
       
         
           
           
               
               
           
         
       
       and
 reacting said compound of Formula VIII with a carboxyl protecting agent under conditions effective to produce a compound of Formula VII. 
 
     
     
         7 . The method according to  claim 1 , wherein said reacting is carried out on a solid support. 
     
     
         8 . A compound prepared according to the method of  claim 1 . 
     
     
         9 . A compound prepared according to the method of  claim 6 . 
     
     
         10 . A peptide having one or more stable, internally-constrained alpha-helical, beta-sheet/beta-turn, 3 10 -helical, or pi-helical regions. 
     
     
         11 . The peptide according to  claim 10 , wherein the one or more stable, internally-constrained regions comprises the following motif: 
       
         
           
           
               
               
           
         
       
       wherein   is a single or double bond,   is a single bond and is cis or trans when   is a double bond; n is 1 or 2; and m is any number. 
     
     
         12 . The peptide according to  claim 11 , wherein the one or more stable, internally-constrained regions comprises the following motif: 
       
         
           
           
               
               
           
         
       
     
     
         13 . The peptide according to  claim 11 , wherein the one or more stable, internally-constrained regions comprises the following motif: 
       
         
           
           
               
               
           
         
       
     
     
         14 . The peptide according to  claim 10 , wherein the one or more stable, internally-constrained regions comprises the following motif: 
       
         
           
           
               
               
           
         
       
     
     
         15 . The peptide according to  claim 10 , wherein said one or more regions comprises a pi helix. 
     
     
         16 . The peptide according to  claim 10 , wherein said one or more regions comprises a beta sheet/beta turn. 
     
     
         17 . The peptide according to  claim 10 , wherein said one or more regions comprises a 3 10  helix. 
     
     
         18 . The peptide according to  claim 10 , wherein said one or more regions comprises an alpha-helix. 
     
     
         19 . The peptide according to  claim 18 , wherein the peptide comprises the formula: 
       
         
           
           
               
               
           
         
         wherein 
         R is hydrogen, an amino acid side chain, an alkyl group, or an aryl group; 
         R 1  is an amino acid side chain, an alkyl group, or an aryl group; 
         R 2  is an amino acid, peptide, OR, CH 2 NH 2 , an alkyl group, or an aryl group; 
         R 6  is (a) a chain of one or more amino acids; or
 (b) a side chain of formula: 
 
       
       
         
           
           
               
               
           
         
       
     
     
         20 . The peptide according to  claim 18 , wherein the peptide comprises the formula: 
       
         
           
           
               
               
           
         
       
     
     
         21 . The peptide according to  claim 18 , wherein the peptide comprises the formula: