馬尿酸

解説尿中に排泄される安息香酸の解毒産物。Nα-ベンゾイルグリシンNα-benzoylglycineともいう。最初、ウマの尿中に発見されたのでこの名でよばれるが、ヒトの尿中にも少量排泄(はいせつ)される。N -ベンゾイルグリシンともいう。化学式 C6H5CONHCH2COOH 。草食動物の尿中に見出される物質で，馬尿から初めて取出されたのでこの名がある。針状晶で，分解点 187℃。グリシンから容易に合成される。肝臓で安息香酸の解毒作用により生成し，尿中に排泄される。ブリタニカ国際大百科事典 小項目事典 ブリタニカ

用途有機合成原料、馬尿酸の定量用。

使用N-Benzoylglycine also known as Hippuric Acid is the glycine conjugate of benzoic acid commonly found in ruminant urine. It is synthesized in the liver and its production is greatly increased following consuption of benzoic acid. In itself it does not have a direct biological function, however p-hydroxy-hippurica acid can be used as an inhibitor of Ca2+ ATPase.

製造方法Preparation of Hippuric acid from Glycine. Principle: The hydroxy and amino functions can be easily benzoylated using Benzoyl chloride in aqueous alkaline conditions. This reaction is known as Schotten-Baumann reaction. Reaction: Procedure: Dissolve 0.5 g of glycine in 5 ml of 10% NaOH solution in a 25 ml conical flask. Add 0.9 ml of benzoyl chloride in five portions to the solution. Stopper the flask and shake vigorously after each addition until all the benzoyl chloride is reacted. Transfer the solution to a beaker and add few grams of ice and add conc. HCl slowly with stirring until the solution is acidic to litmus paper. Filter the crystalline precipitate of the product on a Buchner funnel, wash with cold water and drain well. Place the solid in a conical flask with 10 ml CCl4 and boil gently for 10 min. Allow the mixture to cool slightly, filter under gentle suction and wash with 10-20 ml CCl4. Record the practical yield and re-crystallize it. Re-crystallization: Dissolve the crude product from boiling water (5 ml), with addition of decolorizing charcoal if necessary, filter the hot solution and cool the filtrate. The crystals of the product separate out. Filter, dry and record the melting point and TLC [using Butanal : acetic acid: water (4 : 1 : 1) as solvent or CHCl3:methanol (9 : 1) or toluene].