Fischer reaction of 1-acetyl-3-oxo-2,3-dihydroindole and 1-(p-toluenesuflonyloxy)-3-oxo-2,3-dihydroindole

1-(p-Toluenesulfonyloxy)-3-oxo-2,3-hihydroindole reacted with phenylhydrazine in acetic acid affording 5-(p-toluenesulfonyloxy)indolo[3,2-b]indole. By contrast 1-acetyl-3-oxo-2,3-dihydroindole in the same experimental conditions afforded 12-aminoindolo[1,2-c]quinazoline