A stirred mixture of 4-(3-aminophenoxy)-6-methoxyquinazolin-7-ol from the previous step (500 mg, 1.77 mmol) and phenyl 5-tert-butylisoxazol-3-ylcarbamate (460 mg, 1.77 mmol) in dry N,N-dimethylformamide (10 mL) was heated at 60° C. for 5 h. After cooling to room temperature the mixture was concentrated under reduced pressure. The residue was triturated with diethyl ether and filtered and dried under reduced pressure to afford 1-(5-tert-butylisoxazol-3-yl)-3-(3-(7-hydroxy-6-methoxyquinazolin-4-yloxy)phenyl)urea as a cream solid (650 mg, 82%) which did not require further purification. 1H NMR (300 MHz, DMSO-d6) δ 10.78 (brs, 1H), 9.58 (brs, 1H), 9.00 (brs, 1H), 8.48 (s, 1H), 7.55-7.57 (m, 2H), 7.40 (m, 1H), 7.24-7.26 (m, 2H), 6.97 (m, 1H), 6.48 (s, 1H), 3.99 (s, 3H), 1.28 (s, 9H); LC-MS (ESI) m/z 450 (M+H)+.
