Abstract:
The synthesis of a new derivative of a non-linear azaphenothiazine of industrial importance, 6-(4-bromophenyl)-10-methyl-11-azabenzo[a]phenothiazin-5-one is reported. This was obtained via transition metal catalyzed cross coupling reaction. Alkaline hydrolysis of 2-amino-6-methyl thiozole [4,5b] pyridine in 20% sodium hydroxide solution and neutralization with acetic acid yielded 2-amino-6-methylpyridine-3-thiol. Base catalyzed (anhydrous Sodium carbonate) condensation of 2,3-dichoro-1,4-naphthoquinone and 2-amino-6-methylpyridine-3-thiol gave 6-chloro-10-methyl-11-azabezo[a]phenothiazin-5-one which coupled with 4-bromophenyl boronic acid in the presence of a transition metal catalyst system to furnish the new phenothiazine derivative above. The ease of oxidation of these new heterocyclic compounds to the corresponding sulphoxide using hydrogen peroxide, suggest their applicability as antioxidants in lubricant and fuel. The stability of the iminoquinoid system is attributed to ionic resonance effect.
