An efficient one-pot synthesis of quinazoline-2,4(1H,3H)-diones was developed. First, the reactions of anthranilic acid derivatives with potassium cyanate afforded the corresponding urea derivatives. Then, cyclization of the urea derivatives with NaOH afforded the monosodium salts of benzoylene urea. Finally, HCl treatment afforded the desired products in near-quantitative yields. This is an eco-efficient method because all the reactions were carried out in water, and the desired products were obtained simply by filtration. The aqueous filtrate was the only waste generated from the reaction. We scaled up the reaction to 1 kg starting material, thus establishing an alternative approach for the green synthesis of quinazoline-2,4(1H,3H)-diones in the chemical and pharmaceutical industries.
开发了一种高效的一锅法合成喹嗪-2,4(1H,3H)-二酮。首先,
邻氨基苯甲酸衍
生物与
氰酸钾反应生成相应的
脲衍
生物。然后,
脲衍
生物与
氢氧化钠环化,得到
苯乙烯脲的单钠盐。最后,通过
盐酸处理获得所需产物,产率接近定量。这是一种环保高效的方法,因为所有反应都是在
水中进行的,所需产物仅通过过滤获得。反应中只产生了
水相滤液作为废物。我们将反应规模扩大到1千克起始材料,从而为
化学和制药工业建立了一种绿色合成喹嗪-2,4(1H,3H)-二酮的替代方法。