Methods for synthesizing and purifying aminoalkyl tetracycline compounds

Abstract

Methods for the synthesis and purification of 9-amino alkyl tetracycline compounds are described.

1 . A method of synthesizing an aminoalkyl tetracycline compound, comprising: contacting a tetracycline compound with a N-hydroxymethyl-phthalimide in the presence of a water scavenger and an acid under appropriate conditions, such that an aminomethyl tetracycline intermediate compound is formed. 
     
     
         2 . The method of  claim 1 , wherein the tetracycline compound is minocycline. 
     
     
         3 . The method of  claim 1 , wherein the N-hydroxymethyl phthalimide is of the formula: 
       
         
           
           
               
               
           
         
         wherein R 1  and R 2  are each hydrogen, alkyl, halogen, alkenyl, alkynyl, aryl, cyano, amino, amidino, alkoxy, and acyl. 
       
     
     
         4 . The method of  claim 1 , wherein said appropriate conditions a reaction temperature of about 20-25 C. 
     
     
         5 . The method of  claim 1 , wherein said water scavenger is an acid chloride or an acid anhydride. 
     
     
         6 . The method of  claim 5 , wherein said acid anhydride is methylsulfonic anhydride. 
     
     
         7 . The method of  claim 1 , wherein said acid is triflic acid or methane sulfonic acid. 
     
     
         8 . The method of  claim 1 , wherein said aminomethyl tetracycline intermediate is no more than 10% tris-alkylated. 
     
     
         9 . The method of  claim 1 , wherein said aminomethyl tetracycline intermediate is further dissolved in acetone. 
     
     
         10 . The method of  claim 1 , further comprising treating the aminomethyl tetracycline intermediate with methylamine under second appropriate conditions. 
     
     
         11 . The method of  claim 9 , wherein said second appropriate conditions comprise a alkyl alcohol and an alkyl ether. 
     
     
         12 . The method of  claim 11 , wherein said second appropriate conditions comprise an inert atmosphere. 
     
     
         13 . The method of  claim 10 , wherein after treating the aminomethyl tetracycline intermediate with methylamine under second appropriate conditions, a second aminomethyl tetracycline intermediate is formed. 
     
     
         14 - 15 . (canceled) 
     
     
         16 . A method for the synthesis of an aminoalkyl tetracycline compound, comprising:
 contacting a tetracycline compound with a N-hydroxymethyl-phthalimide in the presence of a water scavenger and an acid under appropriate conditions to form an aminomethyl tetracycline intermediate compound;   treating said aminomethyl tetracycline intermediate compound with methylamine under second appropriate conditions to form a second aminomethyl tetracycline intermediate;   treating said second aminomethyl tetracycline intermediate under appropriate hydrogenation conditions, such that an aminomethyltetracycline compound is formed.   
     
     
         17 - 29 . (canceled) 
     
     
         30 . A method of purifying alkylaminomethyl minocycline compounds, comprising:
 injecting an aqueous low pH solution of said compound into an HPLC in a polar organic solvent gradient, and   combining the product fractions, such that the alkylaminomethyl minocycline compound is purified.   
     
     
         31 - 44 . (canceled) 
     
     
         45 . A method of removing hydrophobic impurities and oxidative degradents from an alkylaminomethyl minocycline compound, comprising dissolving said minocycline compounds in an aqueous solution of a pH of 4.0-4.5, washing said aqueous solution with a non-polar organic solvent, and discarding said non-polar organic solvent and retaining said aqueous solution, such that hydrophobic impurities and oxidative degradents are removed from said alkylaminomethyl minocycline compound. 
     
     
         46 . (canceled) 
     
     
         47 . A method of removing β epimer and by products from an alkylaminomethyl minocycline compound, comprising dissolving said minocycline compounds in an aqueous solution of a pH of 7.5-8.5, washing said aqueous solution with a non-polar organic solvent, and discarding said aqueous solution and retaining said non-polar organic solution, such that β epimer and by products are removed from said alkylaminomethyl minocycline compound. 
     
     
         48 - 53 . (canceled) 
     
     
         54 . A pharmaceutical composition comprising a tetracycline compound synthesized or purified by the method of  claim 1  and a pharmaceutically acceptable carrier. 
     
     
         55 . A method for treating a tetracycline responsive state in a subject, comprising administering to said subject an effective amount of an aminoalkyl tetracycline compound synthesized or purified by the method of  claim 1 , such the tetracycline responsive state is treated. 
     
     
         56 . A method for treating a tetracycline responsive state in a subject, comprising administering to said subject an effective amount of an alkylaminomethyl minocycline compound synthesized or purified by the method of  claim 30 , such the tetracycline responsive state is treated.