Oxalic Acid → (E)-4-Isopropylstyryl-1-(2-pyridyl)-1H-benzimidazole oxalate

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Reaction Steps

Free base of the titled compound was prepared from N-(2-pyridyl)-o-phenylenediamine and 4-isopropylcinnamoyl chloride (Perkin, W. H. J. Chem. Soc., 1877, 31, 388) according to the preparation of (E)-1-(2-pyridyl)-2-styryl-1H-benzimidazole (Example 1, method A). The free base and oxalic acid were dissolved into ethyl acetate. Concentration and recrystallization from ethyl acetate/n-hexane yielded the titled compound. MW: 429.48; mp: 136.0-137.0° C.; 1H-NMR (DMSO) δ: 8.80-8.77 (1H, m), 8.19 (1H, td, J=7.9, 1.8 Hz), 7.86 (1H, d, J=16.1 Hz), 7.77-7.72 (2H, m), 7.67-7.61 (1H, m), 7.53 (2H, d, J=8.1 Hz), 7.47-7.43 (1H, m), 7.36-7.24 (2H, m), 7.27 (2H, d, J=8.4 Hz), 7.12 (1H, d, J=16.1 Hz), 2.52-2.49 (1H, m), 1.20 (6H, d, J=6.6 Hz).

Provenance & Evidence