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A solution of 4-(N,N-bis(2-chloroethyl)amino)-benzaldehyde (IX, n=0) [Anker, R. M., Cook, A. H., "Quinoxaline cyanines. Part IV. Some halogenated styryl derivatives", J. Chem. Soc., 1944 489-4927] (1.32 g, 5.4 mmol) in MeOH (25 mL) was added to a stirred solution of 2,3-diaminobenzonitrile (X) [Stephens, F. F., Bower, J. D., "The preparation of benzimindazoles and benzoxazoles from Schiff's bases. Part II.", J. Chem. Soc., 1950 1722-1726] (0.72 g, 5.4 mmol) in aqueous MeOH (25 mL), immediately followed by a 0.05M aqueous solution of cupric acetate (1.1 mol equiv.). The suspension was brought briefly to the boil and filtered hot. The precipitate was washed with aqueous MeOH and redissolved in conc. HCl. This acid solution was treated with an aqueous solution of Na2S (1.5 mol equiv.) and the precipitated CuS removed by filtration. The filtrate was then basified with conc. ammonia, diluted with water and repeatedly extracted with EtOAc. The combined organic extracts were dried (Na2SO4), filtered and concentrated, and the residue was chromatographed on SiO2. Elution with CH2Cl2 /EtOAc (3:1) yielded 2-[4-(N,N-bis(2-chloroethyl)amino)phenyl]-5-cyanobenzimidazole (XI, n=0) [compound 7 of Table 1] (0.80 g, 40% yield), mp (EtOAc/petroleum ether) 80° C. (dec.). 1H NMR ((CD3)2CO) δ 8.15 (d, J2',3' =9.0 Hz, 2 H, H-2',H-6'), 7.94 (d, J4,6 =1.5 Hz, 1 H, H-4), 7.69 (d, J6,7 =8.5 Hz, 1 H, H-7), 7.50 (dd, J6,7 =8.5 Hz and J4,6 =1.5 Hz, 1 H, H-6), 6.99 (d, J2',3' =9.0 Hz, 2 H, H-3',H-5'), 3.94 (br t, J=7.5 Hz, 4 H, NCH2CH2Cl), 3.83 (br t, J=7.5 Hz, 4 H, NCH2CH2Cl). 13C NMR δ 155.98, 149.75, 143.08, 140.50, 129.62, 126.31, 120.58, 120.13, 118.40, 116.15, 112.93, 105.47, 53.52, 41.43. Anal. (C18H16Cl2N4) C,H,N,Cl.
