Synthesis of 4 H ‐pyrazolo‐ and 4 H ‐pyrrolophenothiazin‐4‐one derivatives

5‐Methyl‐ and 6‐methyl‐2‐phenyl‐2 H ‐indazole‐4,7‐diones were condensed with 2‐aminobenzenethiol or 6‐substituted‐3‐aminopyridine‐2(1 H )thiones 4 to produce a new type of 5‐methyl‐2‐phenyl‐4 H ‐pyrazolophenothiazin‐4‐ones or 8‐substituted‐7‐aza‐5‐methyl‐2‐phenyl‐4 H ‐pyrazolophenothiazin‐4‐one derivatives. From 6‐bromo‐2,5‐dimethyl‐1,3‐diphenyl‐2 H ‐isoindole‐4,7‐dione and 4 8‐substituted‐7‐aza‐2,5‐dimethyl‐1,3‐diphenyl‐4 H ‐pyrrolophenothiazin‐4‐one derivatives were also prepared.