Diethyl Malonate → HCID 18981215, compound

Participants

Reaction Steps

In a 1 liter round-bottom flask equipped with an overhead stirrer and reflux condenser was placed N-(2-hydroxyethyl)-N'-(4-nitrophenyl)urea (40.0 grams, 0.178 mol), diethyl malonate (71.2 grams, 0.445 mol), and ethanol (560 mL). Sodium ethoxide in ethanol (21 wt %, 69.2 grams, 0.214 mol) was added and the reaction mixture was heated to reflux for 6 hours. The reaction mixture was cooled and the ethanol was removed under vacuum. Methylene chloride (500 mL) and water (500 mL) were added. The layers were separated and the aqueous layer was further washed with a second portion of methylene chloride to extract a by-product, 4-nitroaniline which was discarded. The aqueous layer was acidified with 6N HCl (50 mL) and an oily phase precipitated. The oil layer was separated and stirred with 70 mL of benzene. After several minutes the oil turned into a chunky, aggregated solid. The benzene was decanted off and the chunky solid was broken up and triturated with hot benzene. The solution was cooled and suction filtered to isolate the solid, which was oven-dried yielding N-(2-hydroxyethyl)barbituric acid (29.4 grams). Additional product (6.2 grams) crystallized out of the water layer upon standing overnight. The additional product was collected by suction filtration and dried.

Provenance & Evidence