CHEMICAL METHOD

Claims

1. Method for preparing a compound of formula (I) where X is a halogen; wherein said method includes carrying out a reaction of a compound of formula (II) with a halogenating reagent in a suitable reaction medium containing an organic carbonate to obtain a compound of formula (I).

2. The method according to claim 1, wherein X is chlorine or bromine.

3. The method according to claim 1 or 2, wherein X is bromine.

4. The method according to claim 1, wherein the halogenating reagent is selected from the group consisting of bromine, chlorine, iodine, N-bromosuccinimide, N-chlorosuccinimide, N-iodosuccinimide, pyridinium bromide tribromide, copper(II) bromide, sulfuryl chloride and trichloroisocyanuric acid.

5. The method according to claim 3, wherein the halogenating reagent is selected from the group consisting of bromine, N-bromosuccinimide, pyridinium bromide tribromide and copper(II) bromide.

6. The method according to claim 3 or 5, wherein the halogenating reagent is bromine.

7. The method according to any one of claims 1 to 6, wherein the compound of formula (II) is obtained by reacting the compound of formula (III) with an oxidizing reagent in a suitable reaction medium containing an organic carbonate.

8. The method according to claim 7, wherein the oxidizing reagent is sodium hypochlorite.

9. The method according to claim 8, wherein the reaction medium additionally contains sulfuric acid.

10. The method according to any one of claims 1 to 9, wherein the organic carbonate is selected from the group consisting of dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, butylene carbonate and glycerol carbonate.

11. The method according to any one of claims 1-10, wherein the organic carbonate is selected from the group consisting of dimethyl carbonate and diethyl carbonate.

12. The method according to any one of claims 1-11, wherein the intermediate compounds of formula (II) and / or (III) are not isolated.

13. The method according to any one of claims 7 to 12, wherein the compound of formula (III) is obtained by: (i) carrying out the reaction of the compound of formula (IV) with formic acid to obtain a compound of formula (V) (ii) hydrolyzing the compound of formula (V) to a compound of formula (III).

14. The method according to claim 13, wherein the hydrolysis step is carried out using sodium hydroxide.

15. The method according to any one of claims 1 to 14, wherein the method further comprises converting a compound of formula (I) into a compound of formula (VI) where G is selected from the group consisting of hydrogen, C2-C6 alkenyl, C2-C6 alkynyl, C1-C3 alkoxy-C1-C3 alkyl-, -C(O)-R 1 , -C(O)-X a -R 1 and -S(O)2-R 1; X а represents oxygen or sulfur; R 1 selected from the group consisting of C1-C6 alkyl, C2-C6 alkenyl, phenyl and 4-fluorophenyl.