Microwave-Assisted Synthesis of Bis(enaminoketones): Versatile Precursors for Novel Bis(pyrazoles)<i>via</i>Regioselective 1,3-Dipolar Cycloaddition with Nitrileimines
作者:Ahmed H. M. Elwahy、Ahmed F. Darweesh、Mohamed R. Shaaban
DOI:10.1002/jhet.952
日期:2012.9
Synthesis of bis(enaminones) 6a, 6b, 6c and 7a, 7b, 7c was accomplished by the reaction of bis(acetophenones) 3a, 3b, 3c and 4a, 4b, 4c with dimethylformamide–dimethylacetal, under microwave irradiation. 1,3‐Dipolar cycloaddition of bis(enaminones) 6a and 7b, 7c with nitrileimines in refluxing benzene led to the regioselective synthesis of the novel bis(pyrazoles) 11a, 11b, 11c, 11d, 11e, 11f, 11g
双(苯乙酮)3a,3b,3c和4a,4b,4c与二甲基甲酰胺-二甲基乙缩醛在微波辐射下的反应完成了双(烯胺酮)6a,6b,6c和7a,7b,7c的合成。双(烯胺)6a和7b,7c与亚硝基亚胺在回流的苯中的1,3-偶极环加成反应导致新的双(吡唑)11a,11b,11c的区域选择性合成,11d,11e,11f,11g,11h,产率为62-89%。双(吡唑)11b,11c与水合肼缩合,以高收率得到相应的双(吡唑并[3,4- d ]哒嗪)14a,14b。