Abstract: The invention concerns a process for the manufacture of tert-butyl (E)-(6-[2-4-(4-fluorophenyl)-6-isopropyl-2-[methyl(methylsulfonyl)amino]pyrimidin-5-yl]vinyl)-(4R, 6S)-2,2-dimethyl(1,3-dioxan-4-yl) acetate, the novel starting material used in said process and the use of the process in the manufacture of a pharmaceutical.