In a 20 mL scintillation vial was added 2-methyl-6-(piperazin-1-ylmethyl)-8-propyl-2H-benzo[b][1,4]oxazin-3(4H)-one 358E (67 mg, 0.221 mmol) and 4-fluoro-N-methylbenzamide (50.7 mg, 0.331 mmol) in DMSO (1.104 mL) and stirred at 120° C. for 4 h. DBU (0.133 mL, 0.883 mmol) was added and the reaction mixture was stirred at 120° C. for 18 h. The reaction was concentrated in vacuo to remove DBU, and then K2CO3 (61.0 mg, 0.442 mmol) was added. The mixture was heated overnight at 120° C. The reaction was subsequently filtered and the crude material was purified by prep HPLC 20-45% acetonitrile in water. The appropriate fractions were collected and concentrated in vacuo to give the title compound as a yellow solid (18 mg, 0.041 mmol, 18.67% yield). 1H NMR (DMSO-d6, 400 MHz): δ=10.89 (s, 1H), 10.73 (br. s., 1H), 8.04 (br. s., 1H), 7.75 (d, J=8.8 Hz, 1H), 7.24 (s, 1H), 7.11 (s, 1H), 6.95-7.04 (m, 2H), 6.87 (d, J=2.0 Hz, 1H), 4.66-4.72 (m, 1H), 4.64 (d, J=6.6 Hz, 2H), 3.26 (t, J=7.1 Hz, 2H), 3.03 (q, J=6.7 Hz, 2H), 2.30-2.45 (m, 3H), 1.61-1.67 (m, 2H), 1.55 (d, J=6.8 Hz, 5H), 1.40 (d, J=6.8 Hz, 3H), 0.86-0.93 ppm (m, 3H). ESI-MS: m/z 437.4 (M+H)+.
