Appearance: Off-white crystalline power Off-white crystalline power Purity: 99.0% min Melting point: 250~254℃ Loss of drying: 0.5% max Ash: 0.3% max Barbituric acid or malonylurea or 4-hydroxyuracyl is an organic compound based on a pyrimidine heterocyclic skeleton. It is an odorless powder soluble in hot water. Barbituric acid is the parent compound of a large class of barbiturates that have central nervous system depressant properties although barbituric acid itself is not pharmacologically active. The compound was discovered by the German chemist Adolf von Baeyer in 1864 by combining urea and malonic acid in a condensation reaction. Malonic acid has since been replaced by diethyl malonate.