3.25 ml phosphorus oxychloride are added dropwise to 6.50 g 6-(1,4-dioxa-spiro[4.5]dec-8-yloxy)-7-methoxy-3H-quinazolin-4-one in 65 ml acetonitrile under an argon atmosphere. Then the reaction mixture is heated to 40° C., combined dropwise with 5.00 ml triethylamine and refluxed for 2 h. After cooling to ambient temperature 1.40 ml triethylamine and 2.60 ml 3-chloro-2-fluoro-aniline, dissolved in 5 ml acetonitrile, are added and the reaction mixture is stirred overnight at 40° C. Then a further 0.70 ml of 3-chloro-2-fluoro-aniline dissolved in 2 ml acetonitrile are added dropwise and the reaction mixture is stirred for a further 10 h. After cooling to ambient temperature the precipitate formed is suction filtered, taken up in 1 N hydrochloric acid, combined with 6 N isopropanolic hydrochloric acid and stirred at ambient temperature until the ketal cleaving is complete. The precipitate formed is suction filtered and combined with methylene chloride and 1 N sodium hydroxide solution. The aqueous phase is separated off and extracted with methylene chloride, the combined extracts are evaporated down and the flask residue is brought to crystallisation with diisopropylether.
