Pyrrolocoumarin derivatives as potential photoreagents toward DNA

A number of new methyl derivatives of linear and angular pyrrolocoumarins were synthesized by direct Fischer's indole synthesis. In the same way some linear 2H,10H-pyrano2,3-b]carbazol-2-one and angular 2H,7H-pyrano3,2-c]carbazol-2-one were prepared. The synthesis was performed starting from the 4-methyl-7-aminocoumarin and methyl groups were introduced into positions which look most promising for the photoreactivity of the compounds toward DNA.