A solution of (6Z)-5H-dipyrido[2,3-b:4′,3′-f]azepine-5,6(11H)-dione 6-oxime trifluoroacetate (200 mg, 0.4 mmol), 2,6-dichloro-4-(ethylthio)benzaldehyde (200 mg, 0.85 mmol) and ammonium acetate (0.60 g, 8.0 mmol) were stirred in acetic acid (3 mL) and heated in a microwave for 5 minutes at 130° C. Evaporation gave the crude product which was dissolved in acetonitrile (1.0 mL) and triisopropyl phosphate (100 μL, 0.4 mmol) and heated in a microwave for 5 minutes at 180° C. Purification by preparative LCMS gave the desired product LC/MS: 440 (M+H)+.
