1,3-Difurfurylurea

Abstract

A mixture of 19.4 g (0.2 mole) of furfurylamine (see p. 60), b.p. 83°/85 mm, and 50 ml of 20% aqueous sodium hydroxide solution was prepared in a 250-ml four-necked round-bottomed flask fitted with mercury-sealed stirrer, reflux condenser, dropping funnel, and thermometer (see Notes). The mixture was kept at 0° and stirred continuously while a solution of 11–12 g (0.11–0.12 mole) of phosgene in 100 ml of dry benzene was added from the dropping funnel over a period of 60–90 minutes. When the addition was complete, the cooling bath was removed and the mixture was stirred at room temperature for 2.5–3 hours. The precipitated crystals of 1,3-difurfurylurea were filtered off, washed on the filter with 20 ml of water, and dried in the air. Recrystallization from 200 ml of boiling benzene gave 20.5–21.0 g (93.2–95.4%) of pure substance, m.p. 126–128°.