Imatinib production process

1. A process for preparing imatinib or a salt thereof, the process comprising reacting 4-(4-methyl-piperazin-1-ylmethyl)-benzoic acid with N-(5-amino-2-methylphenyl)-4-(3pyridyl)-2-pyrimidine-amine in the presence of a carboxylic acid coupling reagent, to produce imatinib, and optionally converting the imatinib into a salt, wherein the carboxylic acid coupling reagent is a carbodiimide, 2-(5-norborene-2,3-dicarboximido)-1,1,3,3-tetramethyluronium tetrafluoroborate, 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride, 2-[(ethylcarbonimidoyl)amino-N,N,N-trimethyl-ethaneaminium iodide, or N′-(ethylcarbonimidoyl)-N,N-dimethyl-1,2-ethaneamine or the hydrochloride salt thereof.

2. The process of claim 1 , wherein the carboxylic acid coupling reagent is a carbodiimide.

3. The process of claim 2 , wherein the carbodiimide is N-(3-dimethylaminopropyl)-N-ethyl-carbodiimide (EDC) or the hydrochloride salt thereof (EDC HCl).

4. The process of claim 1 , wherein the carboxylic acid coupling reagent is 2-(5-norborene-2,3-dicarboximido)-1,1,3,3-tetramethyluronium tetrafluoroborate, 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride, 2-[(ethylcarbonimidoyl)amino-N,N,N-trimethyl-ethaneaminium iodide, or N′-(ethylcarbonimidoyl)-N,N-dimethyl-1,2ethaneamine or the hydrochloride salt thereof.

5. The process of claim 1 , wherein the coupling reaction is carried out in an aqueous solvent mixture.

6. The process of claim 1 , comprising:

admixing N-(5-amino-2-methylphenyl-4-(3-pyridyl)-2-pyrimidine-amine with 4-(4-methyl-piperazine-1-ylmethyl)-benzoic acid in a solvent mixture comprising water and a first organic solvent;

adding the carboxylic acid coupling reagent and allowing the coupling reaction to proceed to substantial completion to produce imatinib or a salt thereof;

adding a second organic solvent and a base;

extracting the product with an extraction solvent and evaporating at least a portion of the solvent mixture;

adding a third solvent and cooling to precipitate the product; and

isolating the product.

7. The process of claim 6 , further comprising:

purifying the isolated product; and

optionally converting imatinib into the mesylate salt.

8. The process of claim 6 , wherein the first organic solvent is tetrahydrofuran (THF), 2-methyltetrahydrofuran, acetonitrile, N,N-dimethylformamide (DMF), dimethylacetamide (DMA), dimethylsulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), or a mixture thereof.

9. The process of claim 8 , wherein the first organic solvent is THF.

10. The process of claim 9 , wherein the THF:water ratio in the solvent mixture is about 1:1.5 (v/v).

11. The process of claim 6 , wherein the second organic solvent is methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, dichloromethane, chloroform, or a mixture thereof.

12. The process of claim 11 , wherein the second organic solvent is a mixture of ethanol and dichloromethane.

13. The process of claim 6 , wherein the base is ammonia, sodium hydroxide, lithium hydroxide, potassium hydroxide, or a combination thereof.

14. The process of claim 13 , wherein the base is sodium hydroxide.

15. The process of claim 6 , wherein extraction solvent is methanol, ethanol, 1-propanol, 2-propanol, ethyl acetate, dichloromethane, chloroform, toluene, or a mixture thereof.

16. The process of claim 15 , wherein the extraction solvent is a mixture of ethanol and dichloromethane.

17. The process of claim 16 , wherein the ethanol:dichloromethane ratio in the extraction solvent is 1:4 (v/v).

18. The process of claim 6 , wherein the third solvent is methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, or a mixture thereof.

19. The process of claim 18 , wherein the third solvent is ethanol.

20. The process of claim 7 , wherein the isolated product is purified by a crystallization process comprising:

dissolving the isolated product in a first crystallization solvent;

evaporating at least a portion of the first crystallization solvent;

adding a second crystallization solvent to produce a crystallization solvent system and cooling to precipitate imatinib as a purified precipitate; and

isolating the purified precipitate.

21. The process of claim 20 , wherein the crystallization solvent system comprises methanol, ethanol, 1-propanol, 2-propanol, dichloromethane, chloroform or a mixture thereof.

22. The process of claim 21 , wherein the crystallization solvent system is a mixture of dichloromethane and ethanol.

23. The process of claim 7 , comprising reacting imatinib base with methanesulfonic acid to produce imatinib mesylate.