3-(6-(4-(1-aminocyclobutyl)phenyl)-2-oxo-7-phenyl-2,3-dihydro-1H-pyrido[2,3-b][1,4]oxazin-1-yl)propanenitrile 、 tert-butyl(1-(4-(1-(cyanomethyl)-3-methyl-2-oxo-7-phenyl-2,3-dihydro-1H-pyrido[2,3-b][1,4]oxazin-6-yl)phenyl)cyclobutyl)carbamate 以to afford the title compound (20 mg)的产率得到2-(6-(4-(1-aminocyclobutyl)phenyl)-3-methyl-2-oxo-7-phenyl-2,3-dihydro-1H-pyrido[2,3-b][1,4]oxazin-1-yl)acetonitrile