A Straightforward Synthesis of 2-(1-Vinyl-1H-pyrrol-2-yl)-1H-benzimidazoles from 1-Vinyl-1H-pyrrole-2-carbaldehydes and o-Phenylenediamine
作者:Boris Trofimov、Andrei Ivanov、Elena Skital’tseva、Alexander Vasil’tsov、Igor Ushakov、Konstantin Petrushenko、Al’bina Mikhaleva
DOI:10.1055/s-0029-1216996
日期:2009.11
Hitherto inaccessible 1-vinylpyrrole-benzimidazole ensembles have been synthesized by the condensation of 1-vinyl-1H-pyrrole-2-carbaldehydes with o-phenylenediamine either directly or via the intermediate Schiff bases of the 1-vinyl-1H-pyrrole-2-carbaldehydes (1% TFA, DMSO, air atmosphere, 60-70 ËC, 1 h) in yields up to 89%, the intermediate Schiff bases of exclusively E configuration being isolated in 91-98% yield (1% TFA, DMSO, r.t., 30 min). The synthesized 2-(1-vinyl-1H-pyrrol-2-yl)-1H-benzimidazoles are intensely fluorescent, covering the practically important blue region (λmax 343-417 nm, Stokes shift 31-91 nm).
1-vinyl-1H-pyrrole-2-carbaldehydes 与邻苯二胺直接或通过 1-vinyl-1H-pyrrole-2-carbaldehydes 的中间希夫碱(1% TFA、DMSO, air atmosphere, 60-70 ËC, 1 h),收率高达 89%,分离出的专属于 E 构型的中间席夫碱收率为 91-98% (1% TFA, DMSO, r.t.,30 分钟)。合成的 2-(1-乙烯基-1H-吡咯-2-基)-1H-苯并咪唑具有强烈的荧光,覆盖了实际上重要的蓝色区域(δ "max 343-417 nm,Stokes shift 31-91 nm)。