The reaction products of 2 H ‐isoindole‐4,7‐dione derivatives with 2‐aminobenzenethiol

From 2,3,4‐Trisubstituted oxazolium‐5‐oxides and 2‐methyl‐, 2‐phenyl‐ or 2‐bromo‐1,4‐benzoquinone 1,2,3,5‐tetrasubstituted 2 H ‐isoindole‐4,7‐dione derivatives were prepared. These compounds were condensed with 2‐aminobenzenethiol to produce 1,2,3‐trisubstituted or 1,2,3,5‐tetrasubstituted 4 H ‐pyrrolo[3,4‐ a ]phenothiazin‐4‐one derivatives. In the case of 1,2,3‐trisubstituted 5‐methyl‐2 H ‐isoindole‐4,7‐dione 1,2,3,5‐tetrasubstituted 7‐(2‐mercaptophenyl)imino‐2 H ‐isoindole‐4‐one was obtained instead of the expected phenothiazinones.