7,8-Dihydroxy-6-methyl-2-(4-methylphenyl)-4-oxopyrimido[2,1-b][1,3]benzothiazole-3-carbonitrile 、 7,8-dihydroxy-9-methyl-4-oxo-2-(p-tolyl)-4H-benzo[4,5]thiazolo[3,2-a]pyrimidine-3-carbonitrile 、
乙酸酐 在
吡啶 、
4-二甲氨基吡啶 作用下,
反应 5.0h,
生成 3-cyano-7,8-diacetyloxy-6-methyl-4H-2-(4-methyl)phenylpyrimido[2,1-b]benzothiazol-4-one 、 3-cyano-7,8-diacetyloxy-9-methyl-4H-2-(4-methyl)phenyl-pyrimido[2,1-b]benzothiazol-4-one