Sodium triacetoxyborohydride (0.087 g) was added portionwise to a stirred mixture of 4-(6-chloro-2,3-methylenedioxyanilino)-7-isopropoxy-5-piperidin-4-yloxyquinazoline (0.125 g), aqueous formaldehyde (13N, 0.042 ml), acetic acid (0.019 ml), methylene chloride (5 ml) and methanol (2 ml) and the resultant mixture was heated to reflux for 3 minutes. The mixture was evaporated and the residue was partitioned between ethyl acetate and 1N aqueous sodium hydroxide solution. The organic layer was washed with brine, dried over magnesium sulphate and evaporated to give the title compound (0.11 g); NMR Spectrum: (CDCl3) 1.42 (d, 6H), 1.95-2.1 (m, 2H), 2.15-2.25 (m, 2H), 2.3 (s, 3H), 2.3-2.4 (m, 2H), 2.7-2.8 (m, 2H), 4.6 (m, 1H), 4.72 (m, 1H), 6.05 (s, 2H), 6.5 (d, 1H), 6.75 (d, 1H), 6.82 (d, 1H), 6.99 (d, 1H), 8.52 (s, 1H), 9.3 (s, 1H); Mass Spectrum: M+H+ 471 and 473.
