Preparation of New Nitrogen-Bridged Heterocycles 72. A New Approach to 1-Acyl-3-(substituted methylthio)thieno[3',4':4,5]imidazo[1,5-a]pyridine Derivatives
作者:Akikazu Kakehi、Hiroyuki Suga、Yukihisa Okumura、Kennosuke Itoh、Kouji Kobayashi、Yoshihiro Aikawa、Kotaro Misawa
DOI:10.1248/cpb.58.1502
日期:——
corresponding thieno[3',4':4,5]imidazo[1,2-a]pyridine derivatives in low to moderate yields via the intramolecular cyclization of the resulting 1,5-dipoles followed by the aromatization of the primary cycloadducts. Interestingly, the reactions using unsymmetrical 3-amino-4-[1-(3-methylpyridinio)]thiophene-5-thiolates afforded only 8-methylthieno[3',4':4,5]imidazo[1,2-a]pyridines and the other 6-methyl derivatives
吡啶盐的碱处理,很容易从3-氨基-4-(1-吡啶基)噻吩-5-硫醇盐在室温下于氯仿中的3-氨基-4-(1-吡啶基)噻吩-5-硫醇盐的S-烷基化得到,相应的噻吩并[3', 4':4,5]咪唑并[1,2-a]吡啶衍生物,通过对所得的1,5-偶极进行分子内环化,然后进行一级环加合物的芳构化,以低至中等的产率获得。有趣的是,使用不对称的3-氨基-4- [1-(3-(3-甲基吡啶基))噻吩-5-硫醇盐的反应仅得到8-甲基噻吩并[3',4':4,5]咪唑[1,2-a]吡啶和其他6-甲基衍生物根本没有形成。此外,还讨论了吡啶鎓盐与溶剂(CHCl 3)缩合反应中副产物的分离。