Barber, H. J. published the artcileTechnical preparation of dimidium bromide: a new phenanthridine synthesis, Application of Dimidium bromide, the publication is Journal of the Society of Chemical Industry, London, Transactions and Communications (1950), 82-96, database is CAplus.
The Morgan-Walls POCl3 (I) cyclization of 4,4′-dinitro-2-benzamidobiphenyl (II) to 3,8-dinitro-6-phenylphenanthridine (C.A. numbering) (III) (cf. C.A. 42, 682a) involves the readily isolated intermediate 4,4′-dinitro-2-(α-chlorobenzylideneamino)biphenyl (IV), which cyclizes readily only in the presence of inorganic halide catalysts (V). A simpler method for the preparation of III is the V-catalyzed reaction of 4,4′-dinitro-2-aminobiphenyl (VI) and PhCCl3. 3,8-Diamino-6-butoxy-6-phenyl-5-methyl-5,6-dihydrophenanthridine (VII) is valuable for the preparation of III salts. IV, prepared in 83% yield by adding 127 g. PCl5 in 800 ml. PhCl to a stirred suspension of 148 g. II in 800 ml. PhCl at 125°, refluxing 15 min., distilling off I, and cooling, m. 157-8°; refluxing in PhNO2 (VIII) with V until HCl evolution ceased gave III. The most effective V was I; results with a number of other V are reported. The concentration of V had little effect on the yields as long as it was above 0.02 mol.; the optimum temperature was 210°. III was converted to 3,8-dinitro-6-phenyl-5-methylphenanthridinium methosulfate (IX), m. 258-60°, in 88% yield by treating a VIII solution with Me2SO4 at 180° for 45 min.; another 10% was recovered from the crystallization mother liquors as 3,8-dinitro-6-phenyl-6-hydroxy-5-methyl-5,6-dihydrophenanthridine (X) by addition of 2 N NH4OH. BzCl (368 ml.) was added during 10 min. to 777 g. VI in 3 l. VIII at 200°, the mixture held at 185-90° for 30 min., cooled to 130-40° by boiling under reduced pressure, 654 g. PCl5 in 2 l. VIII at 120° added during 10 min., the mixture distilled to a solution temperature of 210°, 20 ml. SnCl4 added, the mixture cooled to 190° after 2 hrs., 600 ml. Me2SO4 added, and the solution was poured after 45 min. at 180° into 4 l. cold H2O, the VIII removed by steam distillation, and the residue treated with NaCl solution to precipitate 80% 3,8-dinitro-6-phenyl-5-methylphenanthridinium chloride. VI (259 g.), 1.5 l. VIII, and 500 ml. C6H6 were distilled to a solution temperature of 210°, cooled to 185°, 120 ml. BzCl added during 20 min., the mixture refluxed 15 min., cooled to 205°, 122 ml. I added, the mixture refluxed 2 hrs., the I distilled, 284 ml. Me2SO4 added to the residue at 190°, the temperature held at 175° for 45 min., the mixture poured into hot H2O, the VIII steam-distilled, the residue diluted to 8 l., filtered, and the filtrate cooled to give 75% IX; the mother liquor with NH4OH gave 20% X. IV was converted to 71% 2-(α-ethoxybenzylideneamino) analog, yellow crystals from EtOAc, m. 161-2°, with Na in alc. The HCl salt (XI) of N,N’-bis(4,4′-dinitro-2-biphenylyl)benzamidine (XII), prepared in 100% yield by heating 25.9 g. VI, 8 ml. PhCCl3, and 1.2 ml. SnCl4 in 120 ml. VIII for 90 min. at 170°, m. 247-50° (decomposition) (slow heating) or 365-70° (rapid heating); XII, prepared by crystallizing XI from C5H5N, m. 180-90° (with loss of solvent of crystallization), then at 248-50°. III, m. 273-4°, was prepared by adding 0.005 mol. V in 5 ml. VIII to 12.9 g. VI in 45 ml. VIII, adding 8 ml. PhCCl3, refluxing 90 min., and cooling. 6-Phenylphenanthridine (XIII), m. 105-6°, and its 8-, m. 238-9°, and 2-nitro derivative, m. 239°, were similarly prepared in 46, 78, and 90% yields, resp. VII was prepared by adding 36 ml. SnCl4 in 480 ml. PhCCl3 during 40 min. to 777 g. VI in 3.5 l. boiling VIII, refluxing 1 hr., distilling off 540 ml. distillate, adding 570 ml. Me2SO4 to the residue at 190°, holding at 180° for 45 min., steam-distilling to remove the VIII, diluting the residue to 17 l., adding 2 N NaOH until the red pseudobase just began to fail to redissolve, filtering hot, adding at 80° to a boiling stirred suspension of 1413 g. reduced Fe in 9 l. H2O, refluxing with stirring for 45 min., filtering, diluting to 29 l., adding 1.2 l. concentrated NH4OH, reboiling, cooling, filtering, stirring with 2.8 l. BuOH, and adding enough 30% NaOH to make the aqueous layer 1.5 N; after 5 min., filtering and washing with H2O, BuOH, and Et2O gave 67% VII. VII was also prepared in 99.5% yield by reducing IX with reduced Fe and treating the product with BuOH and NaOH as above. The complex of XII with PhCl, methylated with Me2SO4 in VIII, gave 29% of the N-Me derivative, m. 344-5°; cyclization of this with PhCCl3 and SnCl4 in VIII gave III and 4,4′-dinitro-2-(N-methylbenzamido)biphenyl, m. 235-6°. VII (825 g.), 224 ml. 82.5% HBr, and 5.16 l. H2O refluxed 30 min., 2.06 l. distilled off, and the residue boiled 5 min. with 16.5 g. charcoal and filtered gave 88.7% 3,8-diamino-6-phenyl-5-methylphenanthridinium bromide (“dimidium bromide”), m. 248° (decomposition). The chloride was prepared in 78% yield by refluxing 10 g. VII, 1.43 g. NH4Cl, and 15 ml. H2O 15 min., filtering, evaporating to 20 ml., cooling, and adding 295 ml. Me2CO.
Journal of the Society of Chemical Industry, London, Transactions and Communications published new progress about 518-67-2. 518-67-2 belongs to bromides-buliding-blocks, auxiliary class Other Aromatic Heterocyclic,Salt,Amine,Benzene, name is Dimidium bromide, and the molecular formula is C20H18BrN3, Application of Dimidium bromide.
Referemce:
https://en.wikipedia.org/wiki/Bromide,
bromide – Wiktionary