Syntheses Of Benzothiazinophenothiazine Derivatives And Evaluation Of Their Antimicrobial Activities

ABSTRACT

The syntheses of benzothiazinophenothiazine derivatives from simple heterocyclic compounds as

precursors is described. Condensation of 2-aminothiophenol with 2,3-dichloro-1,4-naphthoquinone in

an alkaline medium furnished a good yield of the intermediate, 6-chloro-5H-benzo[a]phenothiazin-5-

one. 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 the

benzothiazinophenothiazine ring system. On the other hand, using a facile acid-catalyzed method, the

synthesis of some benzothiazinophenothiazine ring systems were achieved with improved yield and

lesser reaction time. Structures of the compounds were characterized using UV/Visible

spectrophotometry, fourier transform infra red, 1HNMR and 13CNMR spectroscopies and elemental

analysis. The antimicrobial properties of the synthesized compounds were determined against

Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli,

Klebsiella pneumoniae, Candida albican and Aspergillus niger using agar diffusion technique.

Results showed that the complex derivatives were significantly active against the microorganisms.