Synthesis of benzothiazinophenothiazine derivatives and their antimicrobial screening

Abstract

The synthesis of benzothiazinophenothiazine derivatives from simple heterocyclic compounds was thoroughly investigated. The intermediate, 6-chloro-5H-benzo[a]phenothiazin-5- one was afforded by the condensation of 2-aminothiophenol with 2,3-dichloro-1, 4-naphthoquinone in an alkaline medium. Further condensation of the intermediate with 2,4-diamino-6- hydroxypyrimidine-5-thiol obtained by alkaline hydrolysis of 2,4-diamino-6-hydroxy-5- thiacyanatopyrimidine gave 7-amino-9-hydroxy-6-8,diazabenzo[a][1,4]benzothiazino[3,2- c]phenothiazine. However, facile acid-catalyzed synthesis of four other benzothiazinophenothiazine ring systems was accomplished with improved yield and lesser reaction time. The Structural confirmation was done using UV-Visible spectroscopy, FT-IR, 1H and 13C-NMR and elemental analysis. The synthesized compounds were screened against some micro-organisms and the results showed that the complex derivatives were significantly active against the microorganisms.