Synthesis of 3‐substituted 7‐(3,3‐dimethyl‐1‐triazeno)‐10‐methylphenothiazines as potential antitumor agents

Abstract

AbstractA series of 3‐substituted (chloro, bromo, fluoro or methyl) 7‐(3,3‐dimethyl‐1‐triazeno)‐10‐methylphenothiazines were synthesized as potential antitumor agents. Treatment of p‐substituted anilines with ammonium thiocyanate in the presence of bromine gave 6‐substituted 2‐aminobenzthiazoles which, after methylation with methyl iodide were hydrolyzed in 50% potassium hydroxide to give 5‐substituted 2‐methylaminothiophenols in moderate yield. Condensation of methylaminothiophenols with 3,4‐dichloronitrobenzene in ethanol under an atomsphere of nitrogen gave adducts which were cyclized in dimethylformamide under the catalysis of copper and cuprous iodide to give 3‐substituted 7‐nitro‐10‐methylphenothiazines. The nitro group was reduced to the amino function with stannous chloride. Diazotization of the amines followed by coupling with dimethylamine gave the corresponding triazenes.