1H-Benzimidazole-5-carbonitrile,2-(2-aminoethyl)-(9CI) synthesis

Yield:237429-65-1 46% (0.65 g)

Reaction Conditions:

with sodium hydroxide in hydrogenchloride;methanol;

Steps:

9.a 5-Phenyl-2-[2'-(2"-(2-acetamidoethyl)benzimidazol-5"-yl)]benzimidazol-5'-yl]benzimidazole (12).

a. 5-Cyano-2-(2-aminoethyl)benzimidazole. A solution of 3,4 diaminobenzonitrile (1g, 7.52 mmol) and β-alanine (1.0 g, 11.3 mmol) in HCl (8 ml, 6N) was refluxed for 24 hrs. At this time the diamine was barely detectable by TLC. After neutralization with 2N NaOH, the compound was directly loaded on the column. Elution with (75-100%) ethyl acetate/n-hexanes and further with (1-25%) methanol/ethyl acetate gave 46% (0.65 g) of pure yellow compound; mp 105-106° C.; IR (KBr) 3438, 2855, 2734, 2212, 1625, 1569, 1483, 1457, 1385, 1222, 1153; ¹ H NMR (CD₃ 0D) 6 3.09-3.13 (m,4H), 7.49-7.66 (m,2H), 7.91 (d,1H,J=1.46); ¹³ C NMR (CD₃ OD) δ 33.13,40.99, 106.27, 116.57, 121.04, 121.19, 127.08, 140.40, 142.59, 158.82; HRMS (EI) calculated for C₁₀ H₁₀ N₄ m/z 186.0905 found 186.0906.

References:

US6063801,2000,A