Potassium tert-butoxide (998 mg, 8.99 mmol), 2-dicyclohexylphosphino-2,4,6-triisopropyl-biphenyl (X-Phos) (79 mg, 0.18 mmol) and tris-(dibenzylideneacetone)-dipalladium [Pd2(dba)3] (36 mg, 0.036 mmol) were added, under nitrogen, to a mixture of 7-chloro-4-(pyrrolidin-1-yl)quinazoline (A) (840 mg, 3.59 mmol) and tert-butyl piperazine-1-carboxylate (1.0 g, 5.39 mmol) in toluene (49 ml). The reaction mixture was then heated for 15 h at 100° C. The reaction mixture was cooled to room temperature, and water (25 ml) and ethyl acetate (25 ml) were added. The aqueous phase was extracted with ethyl acetate (2×25 ml), and the combined organic phases were washed with saturated sodium chloride solution (20 ml). The organic phase was then dried (MgSO4) and concentrated in vacuo. The crude product was purified by column chromatography (silica gel) using ethyl acetate/-dichloromethane/ammonia solution (25% aq.) (50:10:0.5) and ethyl acetate/dichloro-methane/methyl tert-butyl ether/ammonia solution (25% aq.) (50:10:10:0.7).
