Cyclized-DNAs 5+2 cycloaddition

Bailly and coworkers were interested in synthesizing structures containing a carbazole nucleus with a fused imide ring and examining their effects on DNA, human topoisomerases, and P388 leukemia cells [104]. Thus, the Diels-Alder reaction between the 3-vinylindole species 292 and DMAD (221) was used as the key synthetic step to provide the cycloaddition product 293. This cycloadduct was in turn oxidized to the carbazole moiety 294, bearing a diester functionality that could then be cyclized with an appropriate amine 295 to produce the A-substituted imide ring in the final product 296 (Scheme 62). 

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