Diisopropyl azodicarboxylate (139 μl, 0.71 mmol) was added to a mixture of 4-(4-fluoro-2-methylindol-5-yloxy)-7-hydroxy-6-methoxyquinazoline (200 mg, 0.59 mmol), (prepared as described for the starting material in Example 7), triphenylphosphine (186 mg, 0.71 mmol) and 1-(tert-butoxycarbonyl)-4-hydroxymethylpiperidine, (also known as tert-butyl 4-(hydroxymethyl)piperidine-1-carboxylate), (152 mg, 0.71 mmol) in methylene chloride (3 ml), cooled in an ice/water bath. The mixture was allowed to warm to ambient temperature and was stirred overnight. The mixture was concentrated under reduced pressure and the residue purified by column chromatography, eluting with 1% methanol/methylene chloride and 0.1% triethylamine to give tert-butyl 4-[(4-[(4-fluoro-2-methyl-1H-indol-5-yl)oxy]-6-methoxyquinazolin-7-yloxy)methyl]piperidine-1-carboxylate (293 mg containing 13.5 mol % triphenylphospine oxide, 86%).
