Preparation of New Nitrogen-Bridged Heterocycles. 42. Synthesis and the Reaction of Pyridinium<i>N</i>-Ylides Using Bifunctional Ethyl Thiocyanatoacetates
作者:Akikazu Kakehi、Suketaka Ito、Yasunobu Hashimoto
DOI:10.1246/bcsj.69.1769
日期:1996.6
cycloadditions of some pyridinium (unsymmetrically substituted cyanomethylide)s with dimethyl acetylenedicarboxylate (DMAD) in various solvents afforded only dimethyl 3-cyanoindolizine-1,2-dicarboxylate, except a few examples. On the other hand, the treatment of pyridinium (thiocyanatoaceto)- or (2-thiocyanatopropiono)amidates with a strong base, such as potassium t-butoxide, gave new bicyclic mesoionic compounds
各种吡啶鎓(单取代的甲基化物)在硫氰酸乙酯或 2-硫氰酸根合丙酸乙酯中顺利地攻击氰基,以低到中等的产率得到相应的吡啶鎓(取代的氰基甲基化物),而吡啶鎓(未取代的酰胺化物)与在相同的试剂中酯羰基以可观的产率得到吡啶鎓(硫氰酸根合乙酰基)-或(2-硫氰酸根合丙基)酰胺。除了几个例子外,一些吡啶鎓(不对称取代的氰基甲基化物)与乙炔二甲酸二甲酯 (DMAD) 在各种溶剂中的 1,3-偶极环加成仅得到 3-氰基吲哚腙-1,2-二甲酸二甲酯。另一方面,用强碱(如叔丁醇钾)处理吡啶鎓(硫氰基乙酰基)-或(2-硫氰基丙酸基)酰胺,得到了新的双环介离子化合物 N-[2-(1,3,4-噻二唑并[3,2-a]吡啶并)]乙酰胺衍生物,收率适中。N-[1-(2-thiocyanatopyridinio)]aceta的中间体...