Process for making salts of N-hydroxy-3-[4-[[[2-(2-methyl-1H-indol-3-yl)ethyl]amino]methyl]phenyl]-2E-2-propenamide

1. A method of preparing the lactate monohydrate salt of N-hydroxy-3-[4-[[[2-(2-methyl-1H-indol-3-yl)ethyl]amino]methyl]phenyl]-2E-2-propenamide comprising the steps of:

(a) suspending N-hydroxy-3-[4-[[[2-(2-methyl-1H-indol-3-yl)ethyl]amino]methyl]phenyl]-2E-2-propenamide free base monohydrate in acetone;

(b) adding lactic acid dropwise with stirring at ambient temperature, wherein the lactic acid is present in an equimolar amount;

(c) stirring the reaction mixture for a time sufficient to cause precipitation of the lactate monohydrate salt; and

(d) cooling the reaction mixture.

2. The method of claim 1 further comprising the steps of:

(e) isolating the precipitated lactate monohydrate salt of N-hydroxy-3-[4-[[[2-indol-3-yl)ethyl]amino]methyl]phenyl]-2E-2-propenamide;

(f) washing the salt with cold acetone; and

(g) drying the salt.

3. A method of preparing the anhydrous lactate salt of N-hydroxy-3-[4-[[[2-(2-methyl-1H-indol-3-yl)ethyl]amino]methyl]phenyl]-2E-2-propenamide comprising the steps of:

(a) providing a solution of lactic acid;

(b) suspending N-hydroxy-3-[4-[[[2-(2-methyl-1H-indol-3-yl)ethyl]amino]methyl]phenyl]-2E-2-propenamide free base in water;

(c) heating the suspension to an appropriate temperature;

(d) adding the solution of lactic acid to form a solution;

(e) seeding the solution with a suspension of the anhydrous lactate salt of N-hydroxy-3-[4-[[[2-(2-methyl-1H-indol-3-yl)ethyl]amino]methyl]phenyl]-2E-2-propenamide;

(f) stirring the solution for a time;

(g) heating the solution to a second appropriate temperature;

(h) stirring the solution for a time;

(i) cooling the solution; and

(j) stirring the solution for a time sufficient to precipitate the anhydrous lactate salt of N-hydroxy-3-[4-[[[2-(2-methyl-1H-indol-3-yl)ethyl]amino]methyl]phenyl]-2E-2-propenamide.

4. The method of claim 3 further comprising the steps of:

(k) isolating the precipitated anhydrous lactate salt of N-hydroxy-3-[4-[[[2-(2-methyl-1H-indol-3-yl)ethyl]amino]methyl]phenyl]-2E-2-propenamide;

(l) washing the salt with water; and

(m) drying the salt.

5. A method of preparing the anhydrous lactate salt of N-hydroxy-3-[4-[[[2-(2-methyl-1H-indol-3-yl)ethyl]amino]methyl]phenyl]-2E-2-propenamide comprising the steps of:

(a) providing a solution of lactic acid;

(b) suspending N-hydroxy-3-[4-[[[2-(2-methyl-1H-indol-3-yl)ethyl]amino]methyl]phenyl]-2E-2-propenamide free base in a 1:1 mixture of ethanol and water;

(c) heating the suspension to an appropriate temperature;

(d) adding the solution of lactic acid to form a solution;

(e) cooling the solution;

(f) seeding the solution with anhydrous lactate salt of N-hydroxy-3-[4-[[[2-(2-methyl-1H-indol-3-yl)ethyl]amino]methyl]phenyl]-2E-2-propenamide;

(g) stirring the solution for a time;

(h) cooling the solution; and

(i) stirring the solution for a time sufficient to precipitate the anhydrous lactate salt of N-hydroxy-3-[4-[[[2-(2-methyl-1H-indol-3-yl)ethyl]amino]methyl]phenyl]-2E-2-propenamide.

6. The method of claim 5 further comprising the steps of:

(j) isolating the precipitated anhydrous lactate salt of N-hydroxy-3-[4-[[[2-(2-methyl-1H-indol-3-yl)ethyl]amino]methyl]phenyl]-2E-2-propenamide;

(k) washing the salt with water; and

(l) drying the salt.