Malonic Acid → 2,2'-methylenebis(1h-benzimidazole)

Participants

Reaction Steps

To a flask were added 20 g polyphosphoric acid. After heating to 90 C under nitrogen, a mixture of 5.0 g 1,2-phenylenediamine and 2.4 g malonic acid were added. The reaction mixture was heated to 180 C for 4 hours, then cooled to 150 C and poured into 40 ml water. The mixture was basified with aqueous ammonium hydroxide. After cooling to 5 C, the product was filtered off and washed with water. The solid was reslurried in 200 ml hot acetonitrile, cooled, filtered and dried leaving 2.7 g of a gray solid.

Provenance & Evidence