924271-34-1

Step 2: The product of Step 1 [(2E)-3-(4-bromo-3-methoxyphenyl)acrylic acid] (12.5 g, 48.6 mmol) was used as a raw material, azeotropized with benzene and suspended in benzene (94 mL). Triethylamine (TEA, 9.49 mL, 68.1 mmol) and diphenylphosphoryl azide (10.48 mL, 48.6 mmol) were added sequentially and the reaction mixture was stirred for 1 hour at room temperature. After completion of the reaction, the mixture was filtered through a silica gel pad and eluted with about 1 L of toluene (PhMe). After evaporation to remove volatiles, the residue was resuspended in diphenylmethane (94 mL). The mixture was heated to reflux, maintaining an internal temperature of 250 °C, and reacted for 3 hours. The reaction mixture was cooled to room temperature, stirred overnight and subsequently filtered. The solid was washed with hexane (100 mL) to give the brown solid product 7-bromo-6-methoxyisoquinolin-1(2H)-one (7.4 g).LRMS ESI + (M + H)+ 254.1.

[1] Patent: WO2008/51475, 2008, A2. Location in patent: Page/Page column 36
[2] Patent: EP2268285, 2018, B1. Location in patent: Paragraph 0150; 0151