反应详情

To a stirred solution of 1-(2-amino-pyridin-4-ylmethyl)-1H-benzo[d][1,3]oxazine-2,4-dione (1.2 g, see preparation 7b) in pyridine was added isocyanatoethyl methacrylate (0.76 ml). The reaction mixture was heated to 40° C. and stirred for 2 hours. More isocyanatoethyl methacrylate (0.1 ml) was added and stirring was continued for 2 hours. The solvent was evaporated under reduced pressure and EtOAc (10 ml) was added to the residue. On scraping a solid material formed, that was isolated by filtration and dried in vacuo, affording 2-methyl-acrylic acid 2-{3-[4-(2,4-dioxo-4H-benzo[d][1,3]oxazin-1-ylmethyl)-pyridin-2-yl]-ureido}-ethyl ester (1.78 g). Step 2: This anhydride intermediate was converted into the title compound by reaction with O-(4-cyanobenzyl)hydroxylamine hydrochloride (see preparation 10), using general procedure 1A. 13C-NMR (DMSO-d6) δ 167.5, 166.5, 154.8, 153.7, 151.4, 148.6, 146.6, 141.9, 135.8, 132.8, 132.3, 129.2, 128.1, 125.9, 118.8, 115.4, 114.9, 113.0, 111.6, 110.9, 109.4, 76.1, 63.7, 45.4, 38.0, 18.0.