Readily synthesized biphenyl-2-carbaldehyde O-acetyl oximes were exposed to UV radiation affording phenanthridines. The scope and limitations of this novel reaction were explored. For example, exposure of 2',3'-dimethoxy-[1,1'-biphenyl]-2-carbaldehyde O-acetyl oxime to UV radiation afforded 4-methoxyphenanthridine in 54% yield. This methodology was applied to the synthesis of trisphaeridine to afford the product in four linear steps in an overall yield of 6.5% from 1-bromo-2,4,5-trimethoxybenzene.

中文翻译：

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通过新型光化学介导的环化合成菲啶及其在三苯吡啶合成中的应用

容易合成的联苯-2-甲醛O-乙酰基肟暴露于紫外线辐射下，得到菲啶。探索了这种新反应的范围和局限性。例如，将 2',3'-二甲氧基-[1,1'-联苯]-2-甲醛O-乙酰肟暴露于紫外线辐射下，以 54% 的产率得到 4-甲氧基菲啶。将该方法应用于三环嘧啶的合成，以四个线性步骤从 1-溴-2,4,5-三甲氧基苯中以 6.5% 的总收率得到产物。