咪唑并[1,2-a]吡啶化合物的简便合成

Convenient Method for Synthesis of Imidazo[1,2-a]pyridines

以2-氨基-3-羟基吡啶为原料,经过一锅两步反应合成了12个咪唑并[1,2-a]吡啶类化合物。2-氨基-3-羟基吡啶与N,N-二甲基甲酰胺二甲基缩醛进行反应,几乎定量得到（E）-N＇-（3-羟基吡啶-2-基）-N,N-二甲基甲脒中间体,然后在Na HCO3作用下,于一锅中和活泼亲电化合物（溴乙酸乙酯、溴乙腈和2-溴代苯乙酮）发生合成咪唑环的反应及羟基上的取代反应,以50.3%~85.2%的总收率得到目标产物。该一锅两步方法具有原料易得、反应时间短、操作简便、收率高等优点。

Twelve imidazo[1,2-a]pyridines were prepared from 2-amino-3-hydroxypyridine via a two-step one-pot process. Firstly,2-amino-3-hydroxypyridine reacted with N,N-dimethylformamide dimethyl acetal to afford the intermediate（ E）-N＇-（ 3-hydroxy-pyridin-2-yl）-N,N-dimethylformamidines almost quantitatively,and then followed by the cyclization reaction and the substitution reaction of hydroxyl group with the active electrophiles（ ethyl bromoacetate,bromoacetonitrile and 2-bromoacetophenone） catalyzed by Na HCO3 in one-pot furnishing the target compounds with a yield ranged from 50. 3% to 85. 2%. The synthesis method has the advantages of readily available starting materials,short reaction time,easy workup and high yield.