Synthesis of 1,2,4-Triazolo[4,3-a]pyrimidine Derivatives by Cyclocondensation of a 2-Thioxopyrimidin-4(3H)-one with Hydrazonoyl Halides
作者:Nehal M. Elwan、Enas M. Awad、Hamdi M. Hassaneen、Anthony Linden、Heinz Heimgartner
DOI:10.1002/hlca.200390073
日期:2003.3
The reaction of 1,2-dihydro-6-(phenylamino)-2-thioxopyrimidin-4(3H)one (16) with N-arylhydrazonoyl halides 15 in CHCl3 in the presence of Et3N under reflux afforded the corresponding 1,2,4-triazolo[4,3-a]pyrimidin-5-ones of type 20 in good yields (Scheme 3). The structure of one of the derivatives, 20d, has been established by X-ray crystallography. Conceivable reaction mechanisms are discussed in
的1,2-二氢-6-(苯基氨基)反应-2- thioxopyrimidin-4(3 ħ)一(16)与Ñ -arylhydrazonoyl卤化物15在CHCl 3中的的Et存在下3氮气氛下回流,得到相应的1-类型20的,2,4-三唑并[4,3- a ]嘧啶-5-酮具有良好的收率(方案3)。一种衍生物20d的结构已经通过X射线晶体学确定。流程3和4中讨论了可能的反应机理。类型20的产物容易经历与亲电子试剂如重氮苯酰氯,氯乙酰氯,和纳米反应2的AcOH,得到6-苯基偶氮,6-氯乙酰基,和6-亚硝基衍生物21,23和25,分别为(方案5)。