O-Phenylenediamine → 6-(1H-benzo[d]imidazol-2-yl)pyridin-2-amine

Participants

Reaction Steps

A suspension of 6-aminopyridine-2-carboxylic acid (112 mg), or 2-aminopyridine-4-carboxylic acid (112 mg, 0.82 mmol), or 5-aminopyridine-3-carboxylic acid (112 mg, 0.82 mmol) with 1,2-diaminobenzene (177 mg, 1.64 mmol) was heated in 4 mL of PPA (180 degree) for 2 h. The reaction mixture was each poured into 50 mL ice-water and neutralized with 2 N NaOH (chilled) during vigorous stirring. The resulting precipitate was filtered and washed with 20 mL warm water to afford 105 mg of desired 6-(1H-benzo[d]imidazol-2-yl)pyridin-2-amine (MS, M++H=211.1).

Provenance & Evidence