The condensation products of 2,3,6-trisubstituted-1,4-naphthoquinones with 2-aminothiophenol

The 2,6-disubstituted-, 3,6-disubstituted-5H-benzo[a]phenothiazin-5-one derivatives and 7-substituted-benzo[a] [1,4]benzothiazino[3,2-a]phenothiazine derivatives were prepared by the condensation of 2,3,6-trisubstituted-1,4-naphthoquinones with 2-aminothiophenol. The resulting compounds were subjected to reduction, dehalogenation and condensation with aniline. Some of the condensation intermediates were isolated and the reaction mechanism was also investigated.