Preparation process

1. Process for preparing 5-chloro-N-({(5S)-2-oxo-3-[4-(3-oxo-4-morpholinyl)phenyl]-1,3-oxazolidin-5-yl}methyl)-2-thiophenecarboxamide, comprising reacting 4-{4-[(5S)-5-(aminomethyl)-2-oxo-1,3-oxazolidin-3-yl]phenyl}morpholin-3-one hydrochloride with 5-chlorothiophene-2-carbonyl chloride, wherein the reaction is carried out in a solvent selected from the group of ether, alcohol, ketone and water or in a mixture thereof with use of an inorganic base.

2. Process according to claim 1 , wherein the solvent is a ketone or a mixture of ketone and water.

3. Process according to claim 1 , wherein the inorganic base is sodium hydroxide, sodium carbonate or sodium bicarbonate.

4. Process according to claim 1 , wherein the solvent is an acetone/water mixture and the base is sodium carbonate.

5. Process according to claim 1 , comprising initially charging an aqueous sodium carbonate solution, adding the reactants at a temperature between 10 and 15° C., and then stirring the reaction mixture at 50° C.

6. Process according to claim 1 , comprising recrystallizing the obtained crude product 5-chloro-N-({(5S)-2-oxo-3-[4-(3-oxo-4-morpholinyl)phenyl]-1,3-oxazolidin-5-yl}methyl)-2-thiophenecarboxamide from acetic acid in a subsequent step.

7. Process according to claim 1 , comprising preparing 4-{4-[(5S)-5-(aminomethyl)-2-oxo-1,3-oxazolidin-3-yl]phenyl}morpholine-3-one hydrochloride by eliminating the phthalimide protective group from 2-({(5S)-2-oxo-3-[4-(3-oxo-4-morpholinyl)phenyl]-1,3-oxazolidin-5-yl}methyl)-1H-isoindole-1,3(2H)dione with methylamine in ethanol as solvent, and isolating 4-{4-[(5S)-5-(aminomethyl)-2-oxo-1,3-oxazolidin-3-yl]phenyl}morpholine-3-one as solid hydrochloride.

8. Process according to claim 7 , comprising adding aqueous hydrochloric acid to the reaction mixture at a temperature between 50 and 60° C. until the pH is between 2 and 3 after reacting 2-({(5S)-2-oxo-3-[4-(3-oxo-4-morpholinyl)phenyl]-1,3-oxazolidin-5-yl}methyl)-1H-isoindole-1,3(2H)dione with methylamine.

9. Process according to either of claims 7 or 8 , comprising preparing 2-({(5S)-2-oxo-3-[4-(3-oxo-4-morpholinyl)phenyl]-1,3-oxazolidin-5-yl}methyl)-1H-isoindole-1,3(2H)dione by cyclization of 2-((2R)-2-hydroxy-3-{[4-(3-oxo-4-morpholinyl)-phenyl]amino}propyl)-1H-isoindole-1,3(2H)dione with a phosgene equivalent, wherein the reaction is carried out in toluene as solvent.

10. Process according to claim 9 , comprising isolating 2-({(5S)-2-oxo-3-[4-(3-oxo-4-morpholinyl)phenyl]-1,3-oxazolidin-5-yl}methyl)-1H-isoindole-1,3(2H)dione by filtration.

11. Process according to claim 9 , comprising preparing 2-((2R)-2-hydroxy-3-{[4-(3-oxo-4-morpholinyl)phenyl]amino}propyl)-1H-isoindole-1,3(2H)dione by reacting 2-[(2S)-2-oxiranylmethyl]-1H-isoindole-1,3(2H)-dione with 4-(4-aminophenyl)-3-morpholinone in aqueous ethanol as solvent, wherein the ethanol/water ratio is 1:2.

12. Process according to claim 11 , comprising adding seed crystals of the reaction product 2-((2R)-2-hydroxy-3-{[4-(3-oxo-4-morpholinyl)phenyl]amino}propyl)-1H-isoindole-1,3(2H)dione to the reaction mixture after the reaction has lasted from one to two hours.

13. Process according to claim 12 , comprising heating the reaction mixture under reflux twice towards the end of the reaction time and on each occasion subsequently cooling said reaction mixture again to a reaction temperature of between 55 and 65° C.

14. The process of claim 9 , wherein the phosgene equivalent is N,N-carbonyldiimidazole.