The cyclization of 2-aminobenzophenone (I) with 3-amino-2-chloropyridine (II) by means of NaOH in methylene chloride-water gives 6-phenyl-11H-[2,3-b][1,4]benzodiazepine (III), which is then condensed with (3-chloropropyl)dimethylamine by means of NaH in hot DMF, followed by a treatment with fumaric acid in isopropanol.