Non-concerted nucleophilic [4+1] cycloaddition of (dimethylamino)methoxycarbene to arylazonicotinates in the synthesis of pyrazolo[3,4-c]pyridines and pyrazolo[4′,3′:4,5]pyrido[2,3-d]pyrimidines
作者:Haider Behbehani、Hamada Mohamed Ibrahim、Mohamed H. Elnagdi
DOI:10.1016/j.tet.2013.05.040
日期:2013.7
nucleophilic addition of (dimethylamino)-methoxycarbene, generated from DMF-DMA, to the arylazonicotinates 3c–g. The pyridine derivatives 8 were observed to react with ammonia in refluxing acetic acid to yield novel pyrazolo[4′,3′:4,5]pyrido[2,3-d]pyrimidine derivatives 9. Other members of the pyrido[2,3-d]pyrimidine family 13 were synthesized by reactions between 2-amino-5-arylazonicotinate ethyl esters 3a
之间的新的反应的2-氨基-5- arylazonicotinonitriles 3C -克和二甲基甲酰胺二甲基乙缩醛(DMF-DMA),导致了一类新的吡唑并[3,4的形成Ç ] -吡啶衍生物8,已经研制成功。认为该过程是通过未经证实的[4 + 1]环加成途径进行的,该过程涉及从DMF-DMA生成的亲核加成(二甲氨基)-甲氧基卡宾到芳基氮烟酸酯3c – g。观察到吡啶衍生物8与氨在回流的乙酸中反应,生成新的吡唑并[4',3':4,5]吡啶[2,3- d ]嘧啶衍生物9。吡啶并的其他成员并[2,3- d ]嘧啶家族13通过反应之间合成的2-氨基-5- arylazonicotinate乙酯图3a,b和DMF-DMA,即产生脒衍生物10a中,b 经历环化以产生当在回流的乙酸中用氨处理时,相应的吡啶并[2,3- d ]嘧啶13a,b。最后,该努力的结果表明,吡啶并[2,3- d ]嘧啶13a,b也