2-氧代-2,3-二氢-1H-咪唑并[1,2-a]-吡啶鎓氯化物的合成

Synthesis of 2-oxo-2,3-dihydro-1H-imidazo[1,2-a]-pyridinium chloride

以2-氨基吡啶和氯乙酰氯为原料,合成2-(2-氯乙酰氨基)吡啶,进一步环合生成2-氧代-2,3-二氢-1H-咪唑并[1,2-a]-吡啶鎓氯化物.分别考察物质的量比、反应温度、反应时间对中间体及目标产物收率的影响.通过单因素试验,确定合成2-(2-氯乙酰氨基)吡啶的较佳工艺条件为:氯仿为溶剂,反应温度0℃,反应时间4 h,n(2-氨基吡啶)∶n(氯乙酰氯)=1∶1.5;合成2-氧代-2,3-二氢-1H-咪唑并[1,2-a]-吡啶鎓氯化物的较佳工艺条件为:乙腈为溶剂,反应温度75℃,反应时间12 h.利用1H-NMR和IR对中间体及目标产物结构进行了表征.

2-（2-chloro-acetylamino） pyridine was synthesized with 2-aminopyridine and chloroacetyl chloride, and then 2-oxo-2,3-dihydro-lH-imidazo[1,2-a]-pyridinium chloride was synthesized through cycli- zation reaction. The influences of molar ratio, reaction temperature and time on the yield of intermediate and product were investigated. The synthesis processes of 2-（2-chloro-acetylamino） pyridine and 2-oxo-2,3-di- hydro-lH-imidazo[1,2-a]-pyridinium chloride were determined through the single factor experiment. The opti- mal synthesis process of 2-（2-chloro-acetylamino） pyridine was as follows： the chloroform as solvent, react- ed at 0 ~C for 4 h, the molar ratio of 2-aminopyridine to chloroacetyl chloride was 1 ： 1.5. The optimal synthe- sis process of 2-oxo-2,3-dihydro-lH-imidazo[1,2-a]-pyridinium chloride was as follows： the acetonitrile as solvent, reacted at 75 ℃ for 12 h. The product was characterized by IR and ＇H-NMR.