A solution of 7-bromo-2-ethyl-4H-benzo[1,4]thiazin-3-one (2 g, 7.3 mmol), 3-nitrophenyl boronic acid (1.22 g, 7.3 mmol), potassium carbonate (3 g, 22 mmol), and tetrakis(triphenylphosphine)palladium(0) (0.84 g, 0.72 mmol) in dimethoxyethane (100 ml), ethanol (25 ml), and water (25 ml) was heated to reflux for 6 hours. After cooling to room temperature, the mixture was diluted with water and extracted with EtOAc (3×40 mL). The combined organic extracts were washed with water, then brine, dried (MgSO4) and evaporated. The residue was recrystallized from ethanol to afford the title compound as tan crystals (0.17 g, 7.3%): mp 180° C.; MS (EI) m/z 314 (M+).
