2,4-Dichloro-6-methoxyquinazoline

Synthesis

Method F1: Synthesis of 2,4-dichloro-6-methoxyquinazoline (xa) To a mixture of 6-methoxyquinazoline-2,4(1H,3H)-dione (9.63 g, 50.2 mmol) and phosphorus trichloride (POCl3, 150 mL) was added N,N-dimethylaniline (0.5 mL). The reaction mixture was stirred at 120 °C for 2 hours. Upon completion of the reaction, the excess POCl3 was removed by distillation under reduced pressure. the residue was slowly poured into ice water and the pH was adjusted to about 7 by slowly adding saturated sodium bicarbonate (NaHCO3) solution at 0 °C, where a precipitate was formed. The precipitate was collected and dried under vacuum to give 2,4-dichloro-6-methoxyquinazoline (11.2 g, 98% yield) as a brown solid. LCMS m/z = 229.1, 231.0 [M + 1] (Method B) (retention time = 1.87 min). 1H-NMR (400 MHz, DMSO-d6): δ 7.89 (d, J = 9.2 Hz, 1H), 7.71 (dd, J = 8.8, 2.4 Hz, 1H), 7.38 (d, J = 1.6 Hz, 1H), 3.91 (s, 3H).

References

[1] Patent: US2015/307477, 2015, A1. Location in patent: Paragraph 1497
[2] Patent: JP6121658, 2017, B2. Location in patent: Paragraph 1096; 1099
[3] Patent: US2010/68197, 2010, A1. Location in patent: Page/Page column 17
[4] Bioorganic and Medicinal Chemistry, 2003, vol. 11, # 11, p. 2439 - 2444
[5] Bioorganic and Medicinal Chemistry, 2015, vol. 23, # 24, p. 7717 - 7727