Synthesis
General procedure for the synthesis of 6-methoxy-7-(benzyloxy)quinazolin-4(3H)-one from 6-methoxy-7-hydroxyquinazolin-4-one: Compound 122 (247 g, 875.6 mmol) was dissolved in trifluoroacetic acid (800 mL), followed by a one-time addition of methanesulfonic acid (127 mL). The reaction mixture was heated to reflux and maintained for 3 hours. Upon completion of the reaction, the mixture was cooled to room temperature and concentrated. To the concentrated mixture, 2.5 N of aqueous sodium hydroxide was added and the pH of the solution was adjusted to 7, at which point precipitation was observed to be generated. The resulting solid was pulverized and subjected to vigorous stirring for 1 hour followed by filtration operation. The solid product was collected and dried under high vacuum to give the final compound 123 (148 g, yield = 88%) presenting as a brown solid.
References
[1] Tetrahedron Letters, 2005, vol. 46, # 43, p. 7381 - 7384
[2] Patent: US2014/235634, 2014, A1. Location in patent: Paragraph 0390; 0395
[3] Patent: WO2004/94410, 2004, A1. Location in patent: Page 122
[4] Patent: WO2004/113324, 2004, A1. Location in patent: Page 52
[5] Patent: WO2005/13998, 2005, A1. Location in patent: Page/Page column 60
