O-Phenylenediamine → 2-(5-Methylpyridin-2-yl)benzimidazole

Participants

Reaction Steps

6.2 g. of o-phenylenediamine, 7.1 g. of 5-methylpicolinic acid and 40 g. of polyphosphoric acid were stirred under nitrogen gas current at 160° C. to 180° C. for 4 hours. To the reaction mixture were added 400 ml. of water and then a concentrated aqueous solution of sodium carbonate to neutrality. The resulting crystals were filtered off, dried and recrystallized from acetonitrile or ethyl acetate to obtain 9.4 g. of colorless needles of the product (86% of theory), M.P. 229.0°-229.5° C.

Provenance & Evidence