5-氯代噁唑并[4,5-b]吡啶-2-胺的简便合成

Facile synthesis of 5-chlorooxazolo[4,5-b]pyridin-2-amine

目的简便合成5-氯代噁唑并[4,5-b]吡啶-2-胺,并探索其在合成方面的应用。方法以2-氨基-6-氯吡啶-3-醇(2a)为原料,与BrCN反应得到目标产物5-氯代噁唑并[4,5-b]吡啶-2-胺(1a),并对影响1a收率的主要因素进行研究。结果确定适宜的反应条件为:反应溶剂为水,物料比为n(BrCN)∶n(2a)=1.5∶1,反应温度为70℃,反应时间为3 h。在该条件下,产物1a收率为86.5%。该工艺条件用于5-溴代噁唑并[4,5-b]吡啶-2-胺(1b)的合成,收率为81.9%。结论建立的方法具有反应路线简洁、反应时间短、反应条件温和等优点,该路线对5-氯代噁唑并[4,5-b]吡啶-2-胺的简便合成提供了一条可行的方法。

Objective In order to concisely synthesize 5-chlorooxazolo[4,5-b]pyridin-2-amine and investigate its application in synthesis.Methods The target product of 5-chlorooxazolo[4,5-b]pyridin-2-amine(1a)was synthesized from 2-amino-6-chloropyridine-3-ol(2a)and cyanogen bromide,and the main factors affecting the yield of 1a were investigated.Results The optimal reaction conditions were determined as follows:The reaction solvent was water,the mole ratio of materials n(BrCN)∶n(2a)=1.5∶1,the reaction temperature is 70℃,the reaction time is 3 h,and the yield of 1a was 86.5%.The above conditions were applied to the synthesis of 5-bromooxazolo[4,5-b]pyridin-2-amine(1b),ending with a yield of 81.9%.Conclusion The method proposed here has the advantages of simple synthetic route,short reaction time,mild reaction conditions.The method provids a practical route for the facile synthesis of 5-chlorooxazolo[4,5-b]pyridin-2-amine.