Synthesis of triethylenetetramines

1. A process for preparing triethylenetetramines or triethylenetetramine salts, comprising hydrolyzing in the presence of an acid a compound selected from the group consisting of 2-[3-(2-amino-ethyl)-2-phenyl-imidazolidin-1-yl]-ethylamine, and benzylidene-(2-{3-[2-(benzylidene-amino)-ethyl]-2-phenyl-imidazolidin-1-yl}-ethyl)-amine.

2. The process of claim 1 , wherein said 2-[3-(2-amino-ethyl)-2-phenyl-imidazolidin-1-yl]-ethylamine is prepared by reducing (3-cyanomethyl-2-phenyl-imidazolidin-1-yl)-acetonitrile.

3. The process of claim 1 , wherein said 2-[3-(2-amino-ethyl)-2-phenyl-imidazolidin-1-yl]-ethylamine is prepared by

(a) reacting [2-(cyanomethyl-amino)-ethylamino]-acetonitrile with benzaldehyde to prepare (3-cyanomethyl-2-phenyl-imidazolidin-1-yl)-acetonitrile; and

(b) reducing said (3-cyanomethyl-2-phenyl-imidazolidin-1-yl)-acetonitrile.

4. The process of claim 3 , comprising purifying said (3-cyanomethyl-2-pheny-1-imidazolidin-1-yl)-acetonitrile.

5. The process of claim 1 , wherein said 2-[3-(2-amino-ethyl)-2-phenyl-imidazolidin-1-yl]-ethylamine is prepared by

(a) alkylating ethylenediamine by reacting ethylenediamine with

i. formaldehyde, a cyanide salt, and an acid; or

ii. a haloacetonitrile and a base;

to prepare [2-(cyanomethyl-amino)-ethylamino]-acetonitrile;

(b) reacting [2-(cyanomethyl-amino)-ethylamino]-acetonitrile with benzaldehyde to prepare (3-cyanomethyl-2-phenyl-imidazolidin-1-yl)-acetonitrile; and

(c) reducing said (3-cyanomethyl-2-phenyl-imidazolidin-1-yl)-acetonitrile.

6. The process of claim 1 , wherein said benzylidene-(2-{3-[2-(benzylidene-amino)-ethyl]-2-phenyl-imidazolidin-1-yl}-ethyl)-amine is prepared by reacting triethylenetetramine with benzaldehyde.

7. The process of claim 6 , further comprising purifying said benzylidene-(2-{3-[2-(benzylidene-amino)-ethyl]-2-phenyl-imidazolidin-1-yl}-ethyl)-amine.

8. The process of claim 1 , wherein said benzylidene-(2-{3-[2-(benzylidene-amino)-ethyl]-2-phenyl-imidazolidin-1-yl}-ethyl)-amine is prepared by reacting 2-[3-(2-amino-ethyl)-2-phenyl-imidazolidin-1-yl]-ethylamine with benzaldehyde.

9. The process of claim 1 , wherein said benzylidene-(2-{3-[2-(benzylidene-amino)-ethyl]-2-phenyl-imidazolidin-1-yl}-ethyl)-amine is prepared by

(a) reducing (3-cyanomethyl-2-phenyl-imidazolidin-1-yl)-acetonitrile to form 2-[3-(2-amino-ethyl)-2-phenyl-imidazolidin-1-yl]-ethylamine; and

(b) reacting said 2-[3-(2-amino-ethyl)-2-phenyl-imidazolidin-1-yl]-ethylamine with benzaldehyde.

10. The process of claims 2 , 3 , 5 , or 9 , wherein the reduction is conducted by reaction with LiAlH 3 OMe.

11. The process of claim 1 , wherein said benzylidene-(2-{3-[2-(benzylidene-amino)-ethyl]-2-phenyl-imidazolidin-1-yl}-ethyl)-amine is prepared by

(a) reacting [2-(cyanomethyl-amino)-ethylamino]-acetonitrile with benzaldehyde to produce (3-cyanomethyl-2-phenyl-imidazolidin-1-yl)-acetonitrile;

(b) reducing said (3-cyanomethyl-2-phenyl-imidazolidin-1-yl)-acetonitrile to form 2-[3-(2-amino-ethyl)-2-phenyl-imidazolidin-1-yl]-ethylamine; and

(c) reacting said 2-[3-(2-amino-ethyl)-2-phenyl-imidazolidin-1-yl]-ethylamine with benzaldehyde.

12. The process of claim 11 , comprising purifying said (3-cyanomethyl-2-phenyl-imidazolidin-1-yl)-acetonitrile.

13. The process of claim 1 , wherein said benzylidene-(2-{3-[2-(benzylidene-amino)-ethyl]-2-phenyl-imidazolidin-1-yl}-ethyl)-amine is prepared by

(a) alkylating ethylenediamine by reacting ethylenediamine with

i. formaldehyde, a cyanide salt, and an acid; or

ii. a haloacetonitrile and a base;

to prepare [2-(cyanomethyl-amino)-ethylamino]-acetonitrile;

(b) reacting said [2-(cyanomethyl-amino)-ethylamino]-acetonitrile with benzaldehyde to prepare (3-cyanomethyl-2-phenyl-imidazolidin-1-yl)-acetonitrile;

(c) reducing said (3-cyanomethyl-2-phenyl-imidazolidin-1-yl)-acetonitrile to form 2-[3-(2-amino-ethyl)-2-phenyl-imidazolidin-1-yl]-ethylamine; and

(d) reacting said 2-[3-(2-amino-ethyl)-2-phenyl-imidazolidin-1-yl]-ethylamine with benzaldehyde.

14. The process of claim 1 , wherein said acid is selected from the group consisting of hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, acetic acid, propanoic acid, hydroxyacetic acid, pyruvic acid, oxalic acid, malonic acid, methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-sulfonic acid, cyclamic acid, tartaric acid, succinic acid, malic acid, lactic acid, citric acid, maleic acid, salicyclic acid, p-aminosalicyclic acid, pamoic acid, and fumaric acid.

15. The process of claim 14 , wherein said acid is succinic acid, and wherein said hydrolysis produces triethylenetetramine disuccinate.

16. The process of claim 14 , wherein said acid is hydrochloric acid, and wherein said hydrolysis produces triethylenetetramine tetrahydrochloride.

17. A process for preparing triethylenetetramine or a salt thereof, comprising hydrolyzing in the presence of an acid a compound selected from the group consisting of compounds of formula (I) and formula (III):

wherein R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 may be the same or different, and are hydrogen, an alkyl group of one to twelve carbon atoms, an aryl group, or an aromatic alkyl group.

18. The process of claim 17 , wherein said compound of formula (I) is prepared by reducing a compound of formula (IV)

19. The process of claim 17 , wherein said compound of formula (I) is prepared by

(a) reacting [2-(cyanomethyl-amino)-ethylamino]-acetonitrile with an imidazolidine-forming amine protecting group reagent to prepare a compound of formula (IV)

and

(b) reducing said compound of formula (IV).

20. The process of claim 17 , wherein said compound of formula (I) is prepared by:

(a) alkylating ethylenediamine by reacting ethylenediamine with

i. formaldehyde, a cyanide salt, and an acid; or

ii. a haloacetonitrile and a base;

to prepare [2-(cyanomethyl-amino)-ethylamino]-acetonitrile;

(b) reacting said [2-(cyanomethyl-amino)-ethylamino]-acetonitrile with an imidazolidine-forming amine protecting group reagent to prepare a compound of formula (IV)

and

(c) reducing said compound of formula (IV).

21. The process of claim 17 , wherein said compound of formula (III) is prepared by reacting triethylenetetramine or a salt thereof with an imidazolidine-forming amine protecting group reagent.

22. The process of claim 17 , wherein said compound of formula (III) is prepared by reacting a compound of formula (I) with an imidazolidine-forming amine protecting group reagent.

23. The process of claim 17 , wherein said compound of formula (III) is prepared by

(a) reducing a compound of formula (IV)

to form a compound of formula (I); and

(b) reacting said compound of formula (I) with an imidazolidine-forming amine protecting group reagent.

24. The process of claim 17 , wherein said compound of formula (III) is prepared by

(a) reacting [2-(cyanomethyl-amino)-ethylamino]-acetonitrile with an imidazolidine-forming amine protecting group to form a compound of formula (IV)

(b) reducing said compound of formula (IV) to form a compound of formula (I); and

(c) reacting said compound of formula (I) with an imidazolidine-forming amine protecting group reagent.

25. The process of claim 17 , wherein said compound of formula (III) is prepared by

(a) alkylating ethylenediamine by reacting ethylenediamine with

i. formaldehyde, a cyanide salt, and an acid; or

ii. haloacetonitrile and a base

to prepare [2-(cyanomethyl-amino)-ethylamino]-acetonitrile;

(b) reacting said [2-(cyanomethyl-amino)-ethylamino]-acetonitrile with an imidazolidine-forming amine protecting group to form a compound of formula (IV)

(c) reducing said compound of formula (IV) to form a compound of formula (I); and

(d) reacting said compound of formula (I) with an imidazolidine-forming amine protecting group reagent.

26. The process of claim 17 , wherein said acid is selected from the group consisting of hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, acetic acid, propanoic acid, hydroxyacetic acid, pyruvic acid, oxalic acid, malonic acid, methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-sulfonic acid, cyclamic acid, tartaric acid, succinic acid, malic acid, lactic acid, citric acid, maleic acid, salicyclic acid, p-aminosalicyclic acid, pamoic acid, and fumaric acid.