Functionalization and Antimicrobial Evaluation of New Linear Azo-Phenothiazine Derivatives

Phenothiazine and its derivatives are very important compounds that have many biological and industrial applications. Azo-compounds on the other hand have also been identified to possess good dyeing and biological properties as well. This work is focused on the synthesis of new linear phenothiazine azo-dye compounds via diazotization reaction as well as the determination of their biological activity against some microogrganisms. The above was achieved by the condensation reaction of 3- nitoaniline and phenol in presence of potassium hydroxide and DMF (solvent) to furnished 3-nitrodiphenylamine. Sulphonation of this compound in presence of molecular iodine gave 4-nitro-[10H]-phenothiazine. The conversion of nitro group in 4-nitro-[10H]-phenothiazine to an amino group was achieved by treating it with dilute hydrochloric acid and iron (III) chloride. The amino compound formed, (4-amino-[10H]-phenothiazine) was thereafter converted to an unstable diazonium ion in the presence of sodium nitrite and concentrated hydrochloric. The ion formed above was immediately coupled with the following compounds; 3-nitroaniline, 4-nitroaniline and phenol respectively to furnish four new azophenothiazine compounds namely; 4-azo-(4-amino-2-nitroanilino)-[10H]-phenothiazine, 4-azo-(2-amino-5-nitroanilino)-[10H]- phenothiazine and 4-azo-(4-hydroxyphenyl)-[10H]-phenothiazine with good percentage yields. The synthesized compounds were tested for activity against some microorganisms and they showed some level of inhibition.