To a 20 mL screw cap vial was added 6-bromo-2-methyl-2H-benzo[b][1,4]oxazin-3(4H)-one 19 (100 mg, 0.5 mmol), 3-carboxy phenylboronic acid (91 mg, 0.55 mmol), Pd(PPh3)4 (17 mg, 0.015 mmol), and aqueous Na2CO3 (2M, 0.62 mL, 1.25 mmol) in DMF (4 mL). The reaction was heated at 80° C. overnight then cooled and filtered. The filtrate was purified by preparative HPLC-MS (15-60% MeCN in water). The appropriate fractions were combined and concentrated in vacuo to give a white solid: 1H NMR (DMSO-d6, 400 MHz): δ=13.11 (br. s., 1H), 10.72 (s, 1H), 8.09 (t, J=1.6 Hz, 1H), 7.91 (dt, J=7.6, 1.4 Hz, 1H), 7.80-7.85 (m, 1H), 7.54-7.62 (m, 1H), 7.27 (dd, J=8.3, 2.3 Hz, 1H), 7.20 (d, J=2.0 Hz, 1H), 7.07 (d, J=8.3 Hz, 1H), 4.69-4.77 (m, 1H), 1.45 ppm (d, J=6.8 Hz, 3H). ESI-MS: m/z 284.2 (M+H)+.
