Oxidative condensation−cyclization of aldehydes and aryl-2-pyridylmethylamines proceeded in the presence of a stoichiometric amount of elemental sulfur as an oxidant in the absence of catalyst. The reaction gave a variety of 1,3-diarylated imidazo[1,5-a]pyridines in good to high yields. The products showed fluorescence emission in a wavelength range of 454−524 nm. The quantum yields of 1,3-diarylated imidazopyridines were greatly improved compared to those of the parent 3-monosubstituted compounds.

中文翻译：

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荧光1,3-二芳基咪唑并[1,5- a ]吡啶的合成：以元素硫为氧化剂的芳基-2-吡啶基甲胺和醛的氧化缩合环化

醛和芳基-2-吡啶基甲胺的氧化缩合环化反应在存在化学计算量的元素硫作为氧化剂且没有催化剂的情况下进行。反应以良好至高收率得到各种1，3-二芳基咪唑并[1，5- a ]吡啶。产品显示出在454-524 nm波长范围内的荧光发射。与母体3-单取代的化合物相比，1,3-二芳基咪唑并吡啶的量子产率大大提高。