2,4-Dimethylthiazole-5-carboxylic acid as the starting substrate, acylated with substituted benzoxzinonyl amine to synthesize sixteen novel N-(7-fluoro-2,4-substituted-3-oxo-3,4-dihydro-2H-benzo[b][1,4]oxazin-6-yl)- 2,4-dimethylthiazole-5-carboxamides(3). Their structures were confirmed by IR, ^1H NMR, LC/MS. Preliminary bioassay showed that these novel compounds have different degree fungicidal activities, for example, compounds 3f, 3e and 3g possess 80, 95.5 and 100% fungicidal control at the concentration of 500 mg/L against Erysiphe gra...