O-Phenylenediamine → Methyl 4-(1H-benzo[d]imidazol-2-yl)benzoate

Participants

Reaction Steps

An aqueous solution of NaHSO3 (20.0 mL, 40% in water) was treated with a solution of methyl 4-formylbenzoate (2.20 g, 13.4 mmol) in ethanol (15.0 mL) and stirred at ambient temperature for 1 h. 1,2-benzenediamine (1.45 g, 13.4 mmol) was added and the solution was heated to reflux overnight. Upon cooling, the solution was poured into ice water and the resultant precipitate was collected by filtration, washed with water, and dried in vacuo to provide the title compound as a grey solid (140 g; 100%). NMR (400 MHz, CHLOROFORM-d) ppm 8.19 (d, J=7.8 Hz, 2H) 8.15 (d, J=7.8 Hz, 2H) 7.70 (s, 2H) 7.34 (dd, J=6.1, 3.3 Hz, 2H) 3.98 (s, 3H). MS (ES+) m/e 253 [M+H]+.

Provenance & Evidence