Process for the preparation of 2-(cyclohexylmethyl)-N-{2-[(2S)-1-methylpyrrolidin-2-yl]ethyl}-1,2,3,4-tetrahydroisoquinoline

1. A process for preparing 2-(cyclohexylmethyl)-N-{2-[(2S)-1-methylpyrrolidin-2-yl]ethyl}-1,2,3,4-tetrahydroisoquinoline-7-sulfonamide, or a pharmaceutically acceptable salt thereof, or a solvate or hydrate of a pharmaceutically acceptable salt comprising:

a) reductively aminating 1,2,3,4-tetrahydroisoquinoline, or a salt thereof, with cyclohexanecarboxaldehyde to give 2-cyclohexylmethyl-1,2,3,4-tetrahydroisoquinoline, or a salt thereof;

b) reacting 2-cyclohexylmethyl-1,2,3,4-tetrahydroisoquinoline, or a salt thereof, with excess chlorosulfonic acid to give 2-cyclohexylmethyl-1,2,3,4-tetrahydroisoquinoline-7-sulfonyl chloride HX salt, and optionally recrystallizing the 2-cyclohexylmethyl-1,2,3,4-tetrahydroisoquinoline-7-sulfonyl chloride HX salt;

c) coupling 2-cyclohexylmethyl-1,2,3,4-tetrahydroisoquinoline-7-sulfonyl chloride HX salt with (−)-2-(2-aminoethyl)-1-methylpyrrolidine to form 2-(cyclohexylmethyl)-N-{2-[(2S)-1-methylpyrrolidin-2-yl]ethyl}-1,2,3,4-tetrahydroisoquinoline-7-sulfonamide;

d) optionally reacting 2-(cyclohexylmethyl)-N-{2-[(2S)-1-methylpyrrolidin-2-yl]ethyl}-1,2,3,4-tetrahydroisoquinoline-7-sulfonamide with a stoichiometric amount or an excess of a salt-forming acid in a solvent to form a salt or a hydrate or solvate thereof; and

e) optionally recrystallizing the product of step d).

2. The process according to claim 1 , wherein the reductive amination of step a) is performed in an organic solvent in the presence of a reducing agent.

3. The process according to claim 2 , wherein the reducing agent is selected from the group consisting of sodium triacetoxyborohydride, sodium borohydride, formic acid, and hydrogen with a catalyst.

4. The process according to claim 1 wherein the reaction of step b) is performed in the presence of a co-solvent.

5. The process according to claim 4 , wherein the co-solvent is selected from the group consisting of dichloromethane, chloroform, and 1,2-dichloroethane.

6. The process according to claim 1 , wherein step c) is performed in the presence of an organic solvent.

7. The process according to claim 6 , wherein the organic solvent is selected from the group consisting of dichloromethane, chloroform, 1,2-dichloroethane, methyl t-butyl ether, and toluene.

8. The process according to claim 1 , wherein the salt formed in step d) is a pharmaceutically acceptable salt.

9. The process according to claim 1 , further comprising formulating 2-(cyclohexylmethyl)-N-{2-[(2S)-1-methylpyrrolidin-2-yl]ethyl}-1,2,3,4-tetrahydroisoquinoline-7-sulfonamide or a pharmaceutically acceptable salt thereof, or a solvate or hydrate of a pharmaceutically acceptable salt, with one or more pharmaceutically acceptable carrier agents, bulking agents, solvents, diluents and other excipients.

10. The process according to claim 1 , wherein the salt-forming acid in step d) is fumaric acid to provide 2-(cyclohexylmethyl)-N-{2-[(2S)-1-methylpyrrolidin-2-yl]ethyl}-1,2,3,4-tetrahydroisoquinoline-7-sulfonamide difumarate monohydrate.

11. The process according to claim 10 , further comprising formulating 2-(cyclohexylmethyl)-N-{2-[(2S)-1-methylpyrrolidin-2-yl]ethyl}-1,2,3,4-tetrahydroisoquinoline-7-sulfonamide difumarate monohydrate with one or more pharmaceutically acceptable carrier agents, bulking agents, solvents, diluents and other excipients.

12. The process according to claim 1 , comprising

a) reductively aminating 1,2,3,4-tetrahydroisoquinoline, or a salt thereof, with cyclohexanecarboxaldehyde in the presence of a reducing agent and in an organic solvent to give 2-cyclohexylmethyl-1,2,3,4-tetrahydroisoquinoline, or a salt thereof;

b) reacting 2-cyclohexylmethyl-1,2,3,4-tetrahydroisoquinoline, or a salt thereof, with excess chlorosulfonic acid optionally in the presence of a co-solvent to give 2-cyclohexylmethyl-1,2,3,4-tetrahydroisoquinoline-7-sulfonyl chloride HX salt, and optionally recrystallizing the 2-cyclohexylmethyl-1,2,3,4-tetrahydroisoquinoline-7-sulfonyl chloride HX salt;

c) coupling 2-cyclohexylmethyl-1,2,3,4-tetrahydroisoquinoline-7-sulfonyl chloride HX salt with (−)-2-(2-aminoethyl)-1-methylpyrrolidine in an organic solvent to form 2-(cyclohexylmethyl)-N-{2-[(2S)-1-methylpyrrolidin-2-yl]ethyl}-1,2,3,4-tetrahydroisoquinoline-7-sulfonamide;

d) optionally reacting 2-(cyclohexylmethyl)-N-{2-[(2S)-1-methylpyrrolidin-2-yl]ethyl}-1,2,3,4-tetrahydroisoquinoline-7-sulfonamide with a stoichiometric amount or an excess of a salt-forming acid in a solvent to form a pharmaceutically acceptable salt or a hydrate or solvate thereof; and

e) optionally recrystallizing the product of step d).

13. The process according to claim 12 , further comprising formulating 2-(cyclohexylmethyl)-N-{2-[(2S)-1-methylpyrrolidin-2-yl]ethyl}-1,2,3,4-tetrahydroisoquinoline-7-sulfonamide or a pharmaceutically acceptable salt thereof, or a solvate or hydrate of a pharmaceutically acceptable salt, with one or more pharmaceutically acceptable carrier agents, bulking agents, solvents, diluents and other excipients.

14. The process according to claim 12 , wherein the salt-forming acid in step d) is fumaric acid to provide 2-(cyclohexylmethyl)-N-{2-[(2S)-1-methylpyrrolidin-2-yl]ethyl}-1,2,3,4-tetrahydroisoquinoline-7-sulfonamide difumarate monohydrate.

15. The process according to claim 14 , further comprising formulating 2-(cyclohexylmethyl)-N-{2-[(2S)-1-methylpyrrolidin-2-yl]ethyl}-1,2,3,4-tetrahydroisoquinoline-7-sulfonamide difumarate monohydrate with one or more pharmaceutically acceptable carrier agents, bulking agents, solvents, diluents and other excipients.

16. A process for preparing 2-(cyclohexylmethyl)-N-{2-[(2S)-1-methylpyrrolidin-2-yl]ethyl}-1,2,3,4-tetrahydroisoquinoline-7-sulfonamide comprising the step of reacting 2-cyclohexylmethyl-1,2,3,4-tetrahydroisoquinoline with excess chlorosulfonic acid.

17. The process according to claim 16 wherein the reaction is performed in the presence of a co-solvent.

18. A process for preparing 2-(cyclohexylmethyl)-N-{2-[(2S)-1-methylpyrrolidin-2-yl]ethyl}-1,2,3,4-tetrahydroisoquinoline-7-sulfonamide by coupling 2-cyclohexylmethyl-1,2,3,4-tetrahydroisoquinoline-7-sulfonyl chloride HX salt with (−)-2-(2-aminoethyl)-1-methylpyrrolidine.