In this study, two fast and efficient protocols for green synthesis of 3-substituted quinazolinones were perfomed. A synthesis of 2-methyl-3-substituted quinazolinones was performed in natural deep eutectic solvents, while 3-aryl quinazolinones were obtained by using microwave assisted synthesis. Benzoxazinone, which was used as an intermediate in the synthesis of 2-methyl-3-substituted quinazolinones, was prepared conventionally from anthranilic acid and acetic anhydride. In order to find the most appropriate synthetic path, twenty natural deep eutectic solvents were applied as a solvent in these syntheses. Choline chloride:urea (1 : 2) was found to be the most efficient solvent and was further used in the synthesis of 2-methyl quinazolinone derivatives (2–12). 3-Aryl quinazolinones (13–17), on the other hand, were synthesized in one-pot microwave-assisted reaction of anthranilic acid, different amines and trimethyl orthoformate. All compounds were synthesized in good to excellent yields, characterized by LC-MS/MS spectrometry and 1H- and 13C-NMR spectroscopy.
本研究采用两种快速高效的方法绿色合成 3-取代喹唑啉酮。在天然深共晶溶剂中合成了 2-甲基-3-取代喹唑啉酮,而通过微波辅助合成获得了 3-芳基喹唑啉酮。合成 2-甲基-3-取代喹唑啉酮的中间体苯并噁嗪酮是用蚁酸和乙酸酐通过传统方法制备的。为了找到最合适的合成途径,在这些合成中使用了 20 种天然深共晶溶剂作为溶剂。结果发现氯化胆碱:脲(1:2)是最有效的溶剂,并被进一步用于合成 2-甲基喹唑啉酮衍生物 (2-12)。另一方面,3-芳基喹唑啉酮(13-17)是在蚁酸、不同的胺和原甲酸三甲酯的微波辅助反应中一锅合成的。所有化合物均以良好至极佳的收率合成,并通过 LC-MS/MS 光谱法以及 1H 和 13C-NMR 光谱法进行了表征。