Methods of obtaining 2-methoxyestradiol of high purity

Abstract

2-methoxyestradiol having greater than 98% purity is obtained by synthetic or purification methods. This highly pure 2-methoxy estradiol, lacking estrogenic components, is particularly suitable for clinical use in humans. The purification methods of the invention involve the use of liquid-solid chromatography (LSC) to separate 2-ME2 from other compounds. The chromatographic media is preferably silica. The solvent system comprises a non-polar solvent, such as chloroform, and a polar solvent, such as methanol.

What is claimed is:  
     
         1 . A composition comprising 2-methoxyestradiol having a purity greater than 99.5%.  
     
     
         2 . The composition of  claim 1 , containing less than 0.03% estradiol and less than 0.02% estrone.  
     
     
         3 . The composition of  claim 2 , containing less than 0.01% estradiol and less than 0.01% estrone.  
     
     
         4 . The composition of  claim 2 , further containing less than 0.02% 2-hydroxyestradiol.  
     
     
         5 . The composition of  claim 2 , further containing less than 0.02% 4-hydroxyestradiol.  
     
     
         6 . The composition of  claim 2 , further containing less than 0.02% 4-methoxyestradiol.  
     
     
         7 . The composition of  claim 1 , containing 0.01% or less estradiol, 0.02% or less 2-hydroxyestradiol, 0.01% or less 4-hydroxyestradiol, 0.01% or less 4-methoxyestradiol, and 0.01% or less estrone.  
     
     
         8 . A composition comprising 2-methoxyestradiol having a purity greater than 98.0% and containing less than 0.03% estradiol and less than 0.02% estrone.  
     
     
         9 . The composition of  claim 8 , containing less than 0.01% estradiol and less than 0.01% estrone.  
     
     
         10 . The composition of  claim 8 , containing 0.01% or less estradiol, 0.02% or less 2-hydroxyestradiol, 0.01% or less 4-hydroxyestradiol, 0.01% or less 4-methoxyestradiol, and 0.01% or less estrone.  
     
     
         11 . The composition of  claim 8 , wherein the 2-methoxyestradiol has a purity greater than 99.0%.  
     
     
         12 . The composition of  claim 11 , containing less than 0.01% estradiol and less than 0.01% estrone.  
     
     
         13 . The composition of  claim 11 , containing 0.01% or less estradiol, 0.02% or less 2-hydroxyestradiol, 0.01% or less 4-hydroxyestradiol, 0.01% or less 4-methoxyestradiol, and 0.01% or less estrone.  
     
     
         14 . A method for purifying 2-methoxyestradiol to a produce a 2-methoxyestradiol having a purity greater than 98% and containing les's than 0.03% estradiol and less than 0.02% estrone comprising: 
 adding a solution comprising 2-methoxyestradiol to a chromatography medium; and    eluting the 2-methoxyestradiol off of the medium with a solvent system comprising a polar solvent and a non-polar solvent.    
     
     
         15 . The method of  claim 14 , wherein the medium is silica and wherein the 2-methoxyestradiol is eluted using a step gradient of 99:1 CHCl 3 :MeOH to 98:2 CHCl:MeOH.  
     
     
         16 . A method for producing 2-methoxyestradiol having a purity greater than 98% and containing less than 0.03% estradiol and less than 0.02% estrone comprising: 
 protecting the 3- and 17-hydroxyl groups of estradiol;    reacting the protected estradiol with bromine and acetic acid to produce a 2-brominated derivative of estradiol;    reacting the 2-brominated derivative of estradiol with sodium methoxide in the presence of a copper catalyst;    removing the protecting groups on the 3- and 17-hydroxyl groups to produce 2-methoxyestradiol; and    purifying the 2-methoxyestradiol using liquid chromatography on an adsorption/partition medium with a solvent system comprising a polar and a nonpolar solvent.    
     
     
         17 . A method for producing 2-methoxyestradiol having a purity greater than 98% and containing less than 0.03% estradiol and less than 0.02% estrone comprising: 
 ring-brominating estradiol by reacting estradiol with bromine in the presence of acetic add to produce a ring-brominated intermediate;    reacting the ring-brominated intermediate with sodium methoxide in the present of a copper catalyst to produce 2-methoxyestradiol; and    purifying the 2-methoxyestradiol using liquid chromatography on an adsorption/partition medium with a solvent system comprising a polar and a nonpolar solvent.    
     
     
         18 . A method for producing 2-methoxyestradiol having a purity greater than 98% and containing less than 0.03% estradiol and less than 0.02% estrone comprising: 
 protecting the 3- and 17-hydroxyl groups of estradiol;    reacting the protected estradiol with nitric acid and acetic acid to produce a 2-nitro derivative of estradiol;    reducing the 2-nitro derivative of estradiol to produce the corresponding 2-amino derivative of estradiol;    reacting the 2-amino derivative of estradiol under Sandmeyer conditions to produce a 3-,17-hydroxyl protected 2-methoxyestradiol; and    removing the protecting groups on the 3- and 17-hydroxyl groups to produce 2-methoxyestradiol.    
     
     
         19 . A method for producing 2-methoxyestradiol having a purity greater than 98% and containing less than 0.03% estradiol and less than 0.02% estrone comprising: 
 protecting the 3-hydroxyl group of estrone;    reacting the protected estrone with nitric acid and acetic acid to produce a 2-nitro derivative of estrone;    reducing the 2-nitro derivative of estrone to produce the corresponding 2-amino derivative of estrone;    reacting the 2-amino derivative of estrone under Sandmeyer conditions to produce a 3-hydroxyl protected 2-methoxyestrone;    removing the protecting group on the 3-hydroxyl group to produce 2-methoxyestrone; and    reducing the 17-keto group of 2-methoxyestrone to produce 2-methoxyestradiol.    
     
     
         20 . A method for producing 2-methoxyestradiol having a purity greater than 98% and containing less than 0.03% estradiol and less than 0.02% estrone comprising: 
 brominating estradiol in the presence of acetic acid to produce a mixture of ring-brominated estradiols;    isolating 2-bromoestradiol from the mixture of estradiols; and    reacting the 2-bromoestradiol with sodium methoxide in the presence of a copper catalyst to produce 2-methoxyestradiol.    
     
     
         21 . 2-methoxyestradiol having a purity greater than 98% and containing less than 0.03% estradiol and less than 0.02% estrone produced by the process comprising: 
 protecting the 3- and 17-hydroxyl groups of estradiol;    reacting the protected estradiol with bromine and acetic add to produce a 2-brominated derivative of estradiol;    reacting the 2-brominated derivative of estradiol with sodium methoxide in the presence of a copper catalyst;    removing the protecting groups on the 3- and 17-hydroxyl groups to produce 2-methoxyestradiol; and    purifying the 2-methoxyestradiol using liquid chromatography on an adsorption/partition medium with a solvent system comprising a polar and a nonpolar solvent.    
     
     
         22 . 2-methoxyestradiol having a purity greater than 98% and containing less than 0.03% estradiol and less than 0.02% estrone produced by the process comprising: 
 ring-brominating estradiol by reacting estradiol with bromine in the presence of acetic add to produce a ring-brominated intermediate;    reacting the ring-brominated intermediate with sodium methoxide in the present of a copper catalyst to produce 2-methoxyestradiol; and    purifying the 2-methoxyestradiol using liquid chromatography on an adsorption/partition medium with a solvent system comprising a polar and a nonpolar solvent.    
     
     
         23 . 2-methoxyestradiol having a purity greater than 98% and containing less than 0.03% estradiol and less than 0.02% estrone produced by the process comprising: 
 protecting the 3- and 17-hydroxyl groups of estradiol;    reacting the protected estradiol with nitric add and acetic add to produce a 2-nitro derivative of estradiol;    reducing the 2-nitro derivative of estradiol to produce the corresponding 2-amino derivative of estradiol;    reacting the 2-amino derivative of estradiol under Sandmeyer conditions to produce a 3-,17-hydroxyl protected 2-methoxyestradiol; and    removing the protecting groups on the 3- and 17-hydroxyl groups to produce 2-methoxyestradiol.    
     
     
         24 . 2-methoxyestradiol having a purity greater than 98% and containing less than 0.03% estradiol and less than 0.02% estrone produced by the process comprising: 
 protecting the 3-hydroxyl group of estrone;    reacting the protected estrone with nitric acid and acetic acid to produce a 2-nitro derivative of estrone;    reducing the 2-nitro derivative of estrone to produce the corresponding 2-amino derivative of estrone;    reacting the 2-amino derivative of estrone under Sandmeyer conditions to produce a 3-hydroxyl protected 2-methoxyestrone;    removing the protecting group on the 3-hydroxyl group to produce 2-methoxyestrone; and    reducing the 17-keto group of 2-methoxyestrone to produce 2-methoxyestradiol.    
     
     
         25 . 2-methoxyestradiol having a purity greater than 98% and containing less than 0.03% estradiol and less than 0.02% estrone produced by the process comprising: 
 brominating estradiol in the presence of acetic acid to produce a mixture of ring-brominated estradiols;    isolating 2-bromoestradiol from the mixture of estradiols; and    reacting the 2-bromoestradiol with sodium methoxide in the presence of a copper catalyst to produce 2-methoxyestradiol.