2.97 g (11.2 mmol) of methyl 2-[1-amino-1-(4-fluorophenyl)methylene]-4-methyl-3-oxopentanoate were introduced into 2.45 g (22.4 mmol) of N-methylmethanesulphonamide (MMSA) and 4.19 g (55.9 mmol) of tert-butanol together with 4.51 g (36.6 mmol) of N-cyano-N-methylmethanesulphonamide (CMMSA). 2.22 g (22.4 mmol) of sodium tert-butoxide were added to this suspension at room temperature in portions. An orange-coloured suspension was obtained. It was heated to 50° C. and stirred at 50° C. for 19.9 h. The suspension was poured onto 20 g of ice water, and the precipitate was filtered off and washed with water (2×5 ml). After drying in a high vacuum, 2.91 g of methyl 4-(4-fluorophenyl)-6-isopropyl-2-(N-methanesulphonyl-N-methylamino)pyrimidine-5-carboxylate were obtained in the form of a pale beige solid having a concentration of 76.4% (HPLC), which corresponds to a yield of 52.1%.
