Department of Chemistry, Louisiana State University , Baton Rouge, Louisiana 70803, United States.
J Org Chem. 2017 Sep 15;82(18):9744-9750. doi: 10.1021/acs.joc.7b01940. Epub 2017 Sep 7.
A new synthetic method to build aryl-fused 4,4-difluoro-4-bora-3a,4a-diaza-s-indacenes (BODIPYs) is reported. The intramolecular cyclization step was completed in a short time (1-2 h) and in high yields (>90%), due to the intrinsic rigid structural conformation of the precursor BODIPY and the high reactivity of its 1,7-bromo groups. The [a]phenanthrene-fused BODIPYs 4a-c were characterized by NMR spectroscopy, HRMS, DFT calculations, and, in the case of 4a, by X-ray crystallography. Spectroscopic studies show that 4a-c strongly absorb and emit in the NIR spectral region, in the range 642-701 nm. In addition, BODIPYs 4b and 4c exhibit no toxicity in the light or dark in HEp2 cells and accumulate intracellularly in a time-dependent manner, mainly in the cell endoplasmic reticulum. These results suggest the potential use of [a]phenanthrene-fused BODIPYs as NIR bioimaging probes.
报道了一种新的合成方法，用于构建芳基稠合的 4,4-二氟-4-硼-3a,4a-二氮杂-s-茚并（BODIPY）。由于前体 BODIPY 的固有刚性结构构象和其 1,7-溴基团的高反应性，分子内环化步骤在短时间（1-2 小时）内以高产率（>90%）完成。[a]菲稠合的 BODIPYs 4a-c 通过 NMR 光谱、高分辨率质谱、DFT 计算以及 4a 的 X 射线晶体学进行了表征。光谱研究表明，4a-c 在 NIR 光谱区域（642-701nm）具有强烈的吸收和发射。此外，BODIPYs 4b 和 4c 在 HEp2 细胞中无论是在光照还是黑暗条件下均无毒性，并且以时间依赖性方式在细胞内积累，主要在细胞内质网中。这些结果表明[a]菲稠合的 BODIPY 可作为 NIR 生物成像探针使用。
