Process for preparing tegaserod

• US 20060178519A1
• Filed: 12/22/2005
• Published: 08/10/2006
• Est. Priority Date: 12/23/2004
• Status: Abandoned Application

• Current Assignee: Dr. Reddy's Lab., Inc. (Dr. Reddy's Laboratories Ltd.), Dr. Reddy's Laboratories Ltd.
• Original Assignee: Dr. Reddy's Lab., Inc. (Dr. Reddy's Laboratories Ltd.), Dr. Reddy's Laboratories Ltd.
• Inventors: Singamsetty, Radhakrishna, Reddy, Goverdhan Banda, Brahmeswararao Mandava, Venkata Naga, Gudipati, Srinivasulu, Sundaram, Venkataraman
• Application Number:
  US11/315,859
• Publication Number:
  US 20060178519A1
• Time in Patent Office: Days
• US Class Current: 548/505
• CPC Class Codes: C07D 209/14 Radicals substituted by nitrogen atoms, not forming part of a nitro radical

Abstract

A process for preparing tegaserod.

Claims

1. A process for preparing tegaserod, comprising reacting S-methylthiosemicarbazide hydroiodide with n-pentylamine to form N-pentyl-N-aminoguanidine hydroiodide, in an ester solvent.

2. The process of claim 1, wherein an ester solvent comprises one or more of ethyl acetate, tertiary-butyl acetate, and propyl acetate.

3. The process of claim 1, wherein an ester solvent comprises ethyl acetate.

4. The process of claim 1, wherein a mole ratio of S-methylthiosemicarbazide hydroiodide to n-pentylamine is about 1:

1.02 to 1;

1.5, respectively.

5. The process of claim 1, wherein S-methylthiosemicarbazide hydroiodide is added to n-pentylamine in multiple divided portions.

6. The process of claim 1, wherein N-pentyl-N-aminoguanidine hydroiodide is condensed with 5-methoxy-1H-indole-3-carboxaldehyde in an acidic medium, to form tegaserod.

7. The process of claim 6, wherein N-pentyl-N-aminoguanidine hydroiodide is formed in an ester solvent, and condensed without isolation.

8. The process of claim 6, wherein an acidic medium has a pH about 0.1 to about 5.

9. The process of claim 6, wherein an acidic medium has a pH about 0.5 to about 2.

10. The process of claim 6, wherein formed tegaserod is separated by adjusting pH of a medium to an alkaline value.

11. The process of claim 6, wherein formed tegaserod is separated by adjusting pH of a medium to about 10 to about 14.

12. The process of claim 6, wherein formed tegaserod is separated by adjusting pH of a medium to about 12 to about 13.

13. The process of claim 6, wherein tegaserod is separated and purified by slurrying or crystallization.

14. The process of claim 6, wherein tegaserod is converted to a salt.

15. A process for preparing tegaserod, comprising:

reacting S-methylthiosemicarbazide hydroiodide with n-pentylamine to form N-pentyl-N-aminoguanidine hydroiodide, in an ester solvent; and

condensing N-pentyl-N-aminoguanidine hydroiodide with 5-methoxy-1H-indole-3-carboxaldehyde in an acidic medium, to form tegaserod.

16. The process of claim 15, wherein N-pentyl-N-aminoguanidine hydroiodide is not isolated from an ester solvent, before condensing.

17. The process of claim 15, wherein an ester solvent comprises ethyl acetate.

18. The process of claim 15, wherein a mole ratio of S-methylthiosemicarbazide hydroiodide to n-pentylamine is about 1:

1.02 to 1;

1.5, respectively.

19. The process of claim 15, wherein S-methylthiosemicarbazide hydroiodide is added to n-pentylamine in multiple divided portions.

20. The process of claim 15, wherein an acidic medium has a pH about 0.5 to about 2.