3,7,10-trimethyl-(1H,3H,7H,10H)-pyrimido[5-4-g]pteridine-2,4,6,8-tetrone

丁二酸二乙酯

邻羟基苯甲腈

ethyl 4-oxo-4H-[1]benzopyrano[4,3-c]isothiazole-3-carboxylate

diethyl 3-(o-hydroxyphenyl)4,5-dihydroisothiazole-4,5-dicarboxylate