Process for the preparation of 6-α,9-α-difluoro-17-α-((2-furanylcarbonyl)oxy)-11-β-hydroxy-16-α-methy1-3-oxo-androsta-1,4-diene-17-β- -carbothioic acid S-fluoromethyl

1. A process for preparing a compound of formula (I)

which comprises converting a compound of formula (II)

to a compound of formula (I) via a compound of formula (III), or a salt thereof,

without isolating any intermediates, and wherein the process is performed in methyethylketone or pentan-2-one or mixtures thereof.

2. A process according to claim 1 , wherein the process is performed in methyethylketone as solvent.

3. A process according to claim 1 wherein the compound of formula (II) is converted to the compound of formula (III) by reaction with a deprotecting agent which is an amine base, thiol or alcohol.

4. A process according to claim 3 wherein the amine base is a primary or secondary amine.

5. A process according to claim 4 wherein the amine base is N-methylpiperazine.

6. A process according to claim 1 , wherein the compound of formula (II) is converted to a compound of formula (I) via an organic amine thiolate salt of the compound of formula (III).

7. A process according to claim 6 wherein the organic amine thiolate salt is a trialkylamine salt wherein the trialkylamine group is represented by R 1 R 2 R 3 N wherein each of R 1 , R 2 and R 3 independently represents a C 3-6 straight or branched alkyl group.

8. A process according to claim 7 wherein the organic amine thiolate salt is the tripropylamine or the tributylamine salt.

9. A process according to claim 1 wherein the compound of formula (III) is converted to a compound of formula (I) by reaction with a fluoromethylating agent.

10. A process according to claim 9 wherein the fluoromethylating agent is bromofluoromethane.

11. A process according to claim 10 wherein bromofluoromethane is employed as a solution in methyethylketone.

12. A process according to claim 10 wherein the reaction mixture is treated with a chemical quenching agent to remove excess bromofluoromethane after reaction is complete.

13. A process according to claim 10 wherein after reaction the reaction mixture is extracted into methylisobutylketone by a process comprising dilution with methylisobutylketone.

14. A process according to claim 13 wherein after extraction into methylisobutylketone the solution is worked up and washed with one or more aqueous components.

15. A process according to claim 14 wherein the aqueous components comprise an aqueous acid and an aqueous base and water.

16. A process according to claim 13 , wherein the methylisobutylketone solution is distilled to remove excess bromofluoromethane and water.

17. A process for preparation of a compound of formula (I) according to claim 1 , wherein the compound of formula (II) is prepared by a process which comprises reacting a compound of formula (IV)

or a salt thereof

with an activated 2-furoic acid derivative, wherein said activated 2-furoic acid derivative is a halide or mixed anhydride formed from 2-fuoic acid, and said process is performed without isolating any intermediates.

18. A process according to claim 17 wherein the reaction is performed in pentan-2-one, methyethylketone or mixtures thereof as solvent.

19. A process according to claim 18 wherein the reaction is performed in methyethylketone as solvent.

20. A process according to claim 17 , wherein the activated 2-furoic acid derivative is 2-furoyl chloride.

21. A process according to claim 17 , wherein 4-dimethylaminopyridine is additionally employed.

22. A process according to claim 17 , wherein the compound of formula (IV) is used as an organic amine thiolate salt.

23. A process according to claim 22 wherein the organic amine thiolate salt is a trialkylamine salt wherein the trialkylamine group is represented by R 1 R 2 R 3 N wherein each of R 1 , R 2 and R 3 independently represents a C 3-6 straight or branched alkyl group.

24. A process according to claim 23 wherein the organic amine thiolate salt is the tripropylamine or the tributylamine salt.