Hippuric acid
2207358
220709116
2008-06-21T05:00:56Z
76.87.81.54
/* Uses in medicine */
{{Chembox new
| ImageFile = Hippuric acid.png
| ImageSize =
| IUPACName = Benzoylaminoacetic acid
| OtherNames = Hippuric acid, N-benzoylglycine, benzoyl glycocoll, benzoyl amidoacetic acid
| Section1 = {{Chembox Identifiers
| CASNo = 495-69-2
| PubChem =
| SMILES = O=C(O)CNC(C1=CC=CC=C1)=O
}}
| Section2 = {{Chembox Properties
| Formula = C<sub>9</sub>H<sub>9</sub>NO<sub>3</sub>
| MolarMass = 179.17 g/mol
| Appearance =
| Density =
| MeltingPt = 187 - 188 °C
| BoilingPt = 240 °C (dec.)
| Solubility =
}}
| Section3 = {{Chembox Hazards
| MainHazards =
| FlashPt =
| Autoignition =
}}
}}
'''Hippuric acid''' ([[Greek language|Gr.]] ''hippos'', horse, ''ouron'', urine) is an [[organic acid]] found in the [[urine]] of [[horse]]s and other herbivores. High concentrations of hippuric acid can also indicate a [[Toluene (toxicology)|toluene intoxication]].
When many aromatic compounds such as [[benzoic acid]] and [[toluene]] are taken internally, they are converted to hippuric acid by reaction with the [[amino acid]] [[glycine]]. [[Justus von Liebig]] showed in [[1829]] that hippuric acid differed from benzoic acid, and in 1839 determined its constitution, while in 1873 [[Victor Dessaignes]] synthesized it by the action of [[benzoyl chloride]] on the zinc salt of glycine.<ref>{{cite journal
| title = Ueber die Regeneration der Hippursäure
| author = Dessaignes V.
| journal = Annalen der Chemie und Pharmacie
| volume = 87
| issue = 3
| pages = 325–327
| year = 1853
| url =
| doi = 10.1002/jlac.18530870311}}</ref> It is also formed by heating [[benzoic anhydride]] with glycine, <ref>{{cite journal
| title = Synthese von Hippursäure und Hippursäureäthern
| author = [[Theodor Curtius|Curtius T.]]
| journal = Berichte der deutschen chemischen Gesellschaft
| volume = 17
| issue = 2
| pages = 1662–1663
| year = 1884
| url =
| doi = 10.1002/cber.18840170225}}</ref> and by heating [[benzamide]] with [[monochloroacetic acid]].
Hippuric acid crystallizes in [[rhombic]] prisms which are readily soluble in hot water, melt at 187 °C and decompose at about 240 °C. It is readily [[hydrolyse]]d by hot caustic [[alkali]]s to [[benzoic acid]] and glycine. [[Nitrous acid]] converts it into [[benzoyl glycolic acid]], C<sub>6</sub>H<sub>5</sub>C(=O)OCH<sub>2</sub>CO<sub>2</sub>H. Its ethyl [[ester]] reacts with [[hydrazine]] to form hippuryl hydrazine, C<sub>6</sub>H<sub>5</sub>CONHCH<sub>2</sub>CONHNH<sub>2</sub>, which was used by [[Theodor Curtius]] for the preparation of [[azoimide]].
== Uses in medicine ==
Para-amino-hippuric acid (PAH), a derivative of Hippuric Acid, is a compound useful in medical tests involving the kidney. PAH is completely filtered from [[Blood plasma|plasma]] at the [[glomerulus]] and not reabsorbed by the tubules, in a manner identical to [[inulin]]. PAH is different from inulin in that the fraction of PAH that bypasses the glomerulus and enters the nephron's tubular cells (via the [[Peritubular capillaries]]) is completely secreted. [[Clearance (medicine)|Renal Clearance]] of PAH is thus useful in calculation of renal plasma flow (RPF), which empirically is (1-[[Hematocrit]]) times [[renal blood flow]]. Of note, the clearance of PAH is reflective only of RPF to portions of the kidney that deal with urine formation, and thus underestimates actual RPF by about 10%. <ref>Costanzo, Linda. Physiology, 4th Edition. Philadelphia: Lippincott Williams and Wilkins, 2007. Page 156-160.</ref>
==References==
<references/>
*{{1911}}
==External links==
[http://msds.chem.ox.ac.uk/HI/hippuric_acid.html Safety data] from the chemistry department at Oxford University.
[[Category:Carboxylic acids]]
[[Category:Amides]]
[[de:Hippursäure]]
[[es:Ácido hipúrico]]
[[fr:Acide hippurique]]
[[it:Acido ippurico]]
[[hu:Hippursav]]
[[ja:馬尿酸]]
[[pl:Kwas hipurowy]]
[[ru:Гиппуровая кислота]]