Preparation of {2-[1-(3-benzyl-7-chloro-4-oxo-3,4-dihydro-quinazolin-2-yl)-propylamino]-ethyl}-carbamic acid tert-butyl ester: A mixture of 3-benzyl-2-(1-bromo-propyl)-7-chloro-3H-quinazolin-4-one (3.9 g, 10 mmol) (WO 0130768), (2-amino-ethyl)-carbamic acid tert-butyl ester (2.40 g, 15 mmol) and sodium bicarbonate (1.26 g, 15 mmol) in EtOH (50 mL) was refluxed overnight. The salts were removed by filtration and the filtrate was concentrated to dryness. The residue which remained was purified by flash chromatography on silica gel (10–15% EtOH in hexane) to give the title compound (2.90 g) as a white solid: MS (ES) m/e 471.2 (M+H)+.
