Chemical process
The present invention relates to a process for the preparation of umeclidinium bromide, and to processes for preparing intermediates used in the preparation of umeclidinium bromide.
1. A process for the preparation of a compound of formula (V)
wherein R 1 is C 1-6 alkyl, aryl or benzyl and Y is a leaving group, which process comprises:
a) reacting a compound of formula (VI)
with a compound of formula (VII)
wherein X is a leaving group, in the presence of a suitable base; and
b) converting the product of step (a) to the compound of formula (V) with a suitable reagent.
2. A process according to claim 1 , wherein R 1 is ethyl.
3. A process according to claim 1 , wherein X is Cl or Br.
4. A process according to claim 1 , wherein the reagent in step (b) is selected from the group consisting of thionyl chloride, sulfonyl halides, such as sulfonyl chlorides, sulfonyl anhydrides and phosphorus halides.
5. A process according to claim 4 , wherein the reagent in step (b) is selected from the group consisting of thionyl chloride, p-toluenesulfonyl chloride, methanesulfonyl chloride, methanesulfonic anhydride, p-toluenesulfonic anhydride, trifluoromethanesulfonic anhydride, phosphoryl chloride, phosphorus tribromide and phosphorus pentachloride.
6. A process according to claim 5 , wherein the reagent is thionyl chloride.
7. A process according to claim 1 , wherein steps (a) and (b) are carried out in a suitable solvent.
8. A process according to claim 7 , wherein the solvent is toluene.
9. A process according to claim 1 , wherein the base is DBU.