The biruet can develop the color with the cupric sulfate in the alkaline solution, we call that the biruet reaction.Malonyl urea has acidity, so we call it barbituric acid.

• 巴比妥酸本身无镇静催眠作用，当它的五位亚甲基上的两个氢被烃基取代后才呈现镇静催眠的生理活性，是一类对中枢神经系统起抑制作用的化合物。