To a suspension of 2-methyl-6-[3-(3-methyl-4-oxo-3,4-dihydro-quinazolin-2-ylmethoxy)phenoxymethyl]-benzaldehyde (120 mg, 0.28 mmol, example 102) in t-butanol (1.5 mL) is added iso-butene (0.5 mL) followed by NaClO2 (220 mg, tech grade 1.6 mmol) in water (1.5 mL) and NaH2PO4.H2O (220 mg, 1.6 mmol) in water (1.5 mL). This mixture is stirred for 1 h (during which time the solids dissolve) then diluted with ethyl acetate, washed with water and brine, dried over MgSO4 and concentrated. The residue is purified by flash chromatography (10% methanol in dichloromethane). This product was suspended in chloroform and filtered through celite. The filtrate is concentrated under reduced pressure to give the title compound as an amorphous solid. 1H NMR (300 MHz, CDCl3): δ 8.41 (d, 1H), 7.84 (m, 2H), 7.62 (m, 1H), 7.33 (m, 2H), 7.20 (m, 1H), 7.14 (t, 1H), 6.81 (m, 1H), 6.70 (m, 2H), 5.29 (s, 2H), 5.25 (s, 2H), 3.80 (s, 2H), 2.52 (s, 3H). MS (ESI) 430 (M+H)+.
