4-Chloro-7-ethoxy-6-methoxyquinazoline → 1-(5-Tert-butylisoxazol-3-yl)-3-[3-(7-ethoxy-6-methoxyquinazolin-4-yloxy)phenyl]urea

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Reaction Steps

A mixture of 1-(5-tert-butylisoxazol-3-yl)-3-(3-hydroxyphenyl)urea from Example 1A (0.2 g 0.73 mmol), 4-chloro-7-ethoxy-6-methoxyquinazoline from the previous step (0.18 g, 0.75 mmol), and potassium tert-butoxide (0.252 g, 2.25 mmol) in THF was stirred at room temperature overnight, and then was heated at 60° C. for 5 hours. The reaction was still found to be incomplete and additional 1-(5-tert-butylisoxazol-3-yl)-3-(3-hydroxyphenyl)urea (0.07 g, 0.025 mmol) was added. The mixture was heated further at 60° C. overnight. The reaction was quenched with water and extracted with EtOAc. Extracts were dried over MgSO4 and concentrated under reduced pressure. It was purified by silica gel chromatography with EtOAc/hexane as eluant to afford 1-(5-tert-butylisoxazol-3-yl)-3-[3-(7-ethoxy-6-methoxyquinazolin-4-yloxy)phenyl]urea as a solid (0.078 g). 1H NMR (300 MHz, CDCl3) δ 9.12 (br and s, 2H), 8.61 (s, 1H), 7.64 (s, 1H), 7.54 (s, 1H), 7.31 (m, 3H), 7.0 (d, 1H), 6.05 (s, 1H), 4.29 (q, 2H), 4.05 (s, 3H), 1.58 (t, 3H), 1.30 (s, 9H); LC-MS (ESI) m/z 478 (M+H)+.

Provenance & Evidence