O-Phenylenediamine → Benzimidazol-2-one

Participants

Reaction Conditions

Reaction Steps

216 Parts of o-phenylenediamine and 193.6 parts of N,N'-dimethyl urea are heated in 1000 parts of o-dichlorobenzene for 2 hours to 172° C. Methylanine evolves at 130° C. The suspension is stirred for a further 4 hours at 172° C, then cooled to room temperature and filtered by suction. The filter cake is washed with 800 parts by volume of ethanol and suspended in 1000 parts of water. This suspension is filtered by suction, washed with 100 parts of water and the filter cake is dried at 100° C, giving 250.8 parts (93.6% of theory) of benzimidazolone. The melting point of the product is between 312° and 315° C.

Provenance & Evidence