5-Chloro-2-methoxy-N-formylaniline (I) is reacted with 2-bromoanisole at 220 C in the presence of Na2CO3 and Cu(I)Br in Dowtherm A to give the diphenylamine (II), which is demethylated with anhydrous AlCl3 in chlorobenzene. The product (III) is cyclized with CH2Br2 in refluxing 2-butanone in the presence of K2CO3, then hydrolyzed with NaOH in boiling ethanol to give the dioxazocine (IV). The lat ter is condensed with 3-dimethylamino-2-methyl-1-chloropropane (V) in refluxing xylene in the presence of NaOH and the resulting base (VI) transtormed to EGYT-2509 by treatment with HCl in isopropanol.