Patent ID: 8703945

Claim:
A process for the preparation of a compound of formula (7): wherein R 1 represents an isopropyl group; R 2 represents a 4-fluorophenyl group; R 3 represents a methyl group; and R 4 represents a SO 2 R 5 group where R 5 is a methyl group, comprising the steps of: a) hydroxylating a compound of formula (1): wherein Y represents a halo group; P 1 represents hydrogen or a protecting group selected from the group consisting of benzyl, benzoyl, methyl, silyl, and tetrahydropyranyl; and W represents —OP 2 , in which P 2 represents a protecting group selected from the group consisting of benzyl, benzoyl, methyl, silyl, and tetrahydropyranyl, to give a compound of formula (2): b) oxidising the compound of formula (2) to give a compound of formula (3): c) coupling the compound of formula (3) with a compound of formula (4): wherein R 1 represents an isopropyl group; R 2 represents a 4-fluorophenyl group; R 3 represents a methyl group; R 4 represents SO 2 R 5 group where R 5 is a methyl group; and R 6 represents P(═O)R 7 R 8 in which R 7 and R 8 each independently is a C 1-6 alkyl, C 6-12 aryl, C 1-6 alkoxy, or C 6-12 aryloxy group, to give a compound of formula (5): wherein R 3 represents a methyl group; and R 4 represents a SO 2 R 5 group where R 5 is methyl group; d) removing the P 2 protecting group and oxidising the compound of formula (5) to give a compound of formula (6): and e) subjecting the compound of formula (6) to ring-opening and removing any P 1 protecting group, to give a compound of formula (7).