522 mg of 3-thienylboronic acid, 1.24 g of caesium fluoride, 13 mg of palladium acetate and finally 31 mg of 2-dicyclohexylphosphine-2-(N,N-dimethylamino)biphenyl are added to 1 g of N-[6-chloro-1-[[2-(trimethylsilyl)ethoxy]methyl]-1H-indazol-3-yl]butanamide, described previously in Example 25, in 30 cm3 of dioxane. The mixture is then heated at about 100° C. for 2 hours. 31 mg of 2-dicyclohexylphosphine-2-(N,N-dimethylamino)biphenyl and 13 mg of palladium acetate are added and the mixture is refluxed for 17 hours. The mixture is then allowed to return to about 19° C. and then filtered through a sinter funnel, and 75 cm3 of ethyl acetate and 50 cm3 of distilled water are added. The insoluble material is filtered off on a sinter funnel. The organic phase is dried over magnesium sulphate, filtered through a sinter funnel and then evaporated under reduced pressure under the conditions described previously. The residue is purified by chromatography under an argon pressure of 50 kPa, on a column of silica gel (particle size 40-60 μm; diameter 4.5 cm), eluting with a cyclohexane/ethyl acetate mixture (90/10 by volume) and collecting 50 cm3 fractions. The fractions containing the expected product are combined and evaporated under reduced pressure (2 kPa; 50° C.). 570 mg of N-[6-(3-thiophenyl)-1-[[2-(trimethylsilyl)ethoxy]methyl]-1H-indazol-3-yl]butanamide are obtained in the form of a yellow oil.
