Solid form of 4-[[(6-chloropyridin-3-yl)methyl](2,2-difluoroethyl)amino]furan-2(5H)-one

1. A process for preparing a solid form of 4-[[6-chloropyridin-3-yl)methyl](2,2-difluoroethyl)amino]furan-2(5H)-one having a melting point of 65° C. to 75° C. comprising:

(a) dissolving 4-[[(6-chloropyridin-3-yl)methyl](2,2-difluoroethyl)amino]furan-2(5H)-one in a solvent or solvent mixture at a temperature of at least 30° C. to form a crystallization solution, and

(b) cooling the solution.

2. A process according to claim 1 where the cooling takes place in a step-wise manner.

3. A process according to claim 1 in which the solvent or solvent mixture is selected from the group consisting of isopropanol, toluene, methyl-THF, diethyl carbonate, chlorobenzene, n-butyl acetate and isobutyl acetate, n-butanol, ethanol, ethyl malonate, methyl t-butyl ether, and mixtures of toluene and butanol, of toluene and n-butyl acetate, of ethyl malonate and methyl t-butyl ether, and of butyl acetate and methyl t-butyl ether.

4. A process according to claim 1 wherein the solid form of 4-[[(6-chloro-pyridin-3-yl)methyl](2,2-difluoroethyl)amino]furan-2(5H)-one has a melting point in the range of 72° C. to 74° C.

5. The process according to claim 1 wherein the solid form of 4-[[(6-chloro-pyridin-3-yl)methyl](2,2-difluoroethyl)amino]furan-2(5H)-one is characterized by an X-ray powder diffractogram at 25° C. having the 2Θ (2 theta) values below:

2Θ=16.8°

2Θ=17.8°

2Θ=20.2°

2Θ=21.7°

2Θ=23.6°

2Θ=23.9°

2Θ=24.7°

2Θ=25.3°.

6. A process according to claim 1 wherein 4-[[(6-chloropyridin-3-yl)methyl](2,2-difluoroethyl)amino]furan-2(5H)-one is dissolved in step (a) at a temperature of at least 50° C.

7. A process according to claim 3 wherein the crystallization solution is stirred at about 40° C.

8. A process according to claim 7 wherein the crystallization solution is stirred at about 40° C. for 2 to 20 hours.

9. A process according to claim 7 wherein the crystallization solution is stirred at about 40° C. for 4 to 20 hours.

10. A process according to claim 7 wherein the crystallization solution is stirred at about 40° C. for 4 to 16 hours.

11. A process according to claim 1 wherein seed crystals are added to the crystallization solution.

12. A process according to claim 11 wherein seed crystals are added after stirring.

13. A solid form of 4-[[(6-chloropyridin-3-yl)methyl](2,2-difluoroethyl)amino]furan-2(5H)-one produced by a process according to claim 1 .