3-甲基-3,4-二氢-2H-1,4-苯并噁嗪合成工艺的研究

Studies on the Synthesis of 3-Methyl-3,4-Dihydro-2H-1,4-Benzoxazine

探索以邻硝基苯酚、1-氯丙酮为原料,铂碳为催化剂,通过O-烷基化、还原、环合反应,合成3-甲基-3,4-二氢-2H-1,4-苯并噁嗪。利用四因素三水平正交实验设计研究了还原-环合反应过程中溶剂效应、反应温度、搅拌时间、反应压力对标题化合物产率的影响,确定了合成标题化合物的优化工艺条件为：以甲苯为溶剂,反应温度45-50℃,反应时间15 h,反应压力2.0 MPa,合成收率达92.5%。产物结构经红外光谱、核磁共振和元素分析进行了表征。本方法原料廉价易得,产物收率高,适用于工业化生产。

A 3-methyl-3,4-dihydro-2H-1,4-benzoxazine synthetic route was investigates which consists of O-alkylation, reduction, and ring closure reactions, and o-nitrophenol and 1-chloro-acetone were used as the reactants and with Pt/C as the catalyst. Factors affecting reaction yield such as solvent, reaction temperature, stirring time and reaction pressure were studied under orthogonal experimental design. The optimum synthetic conditions were found as： using toluene as the solvent under reaction temperature of 45-50℃, stirring time of 15 h and pressure of 2.0 MPa, the yield could reach to 92.5%. Moreover, the structures of the obtained compounds were characterized by IR, 1H-NMR, 13C-NMR and elemental analysis. This study shows that the proposed synthetic route is simple with high yields, and the raw materials are cheap and easy to obtain.