To a stirred mixture of 4-(2,4-dioxo-4H-benzo[d][1,3]oxazin-1-ylmethyl)-benzonitrile (Preparation 7D, 319 mg) and O-(4-chloro-benzyl)-hydroxylamine hydrochloride (preparation 9, 267 mg) in DMF (10 ml) was added N-ethyldiisopropylamine (0.4 ml). The reaction mixture was heated to 100° C. and stirred for 17 hours. The mixture was cooled to room temperature and water was added. The pale brown precipitated material was isolated by filtration and re-crystallised from ethanol and gave the title compound as a white solid material. 13C-NMR (DMSO-d6) δ 148.2, 145.9, 135.1, 132.8, 132.5, 132.3, 130.6, 128.2, 128.0, 127.7, 118.8, 114.8, 113.2, 111.4, 109.5, 75.9, 45.4.
