Hippuric acid
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| Hippuric acid[1] | |
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| Chemical name | Benzoylaminoacetic acid |
| Other names | Hippuric acid N-Benzoylglycine Benzoyl glycocoll Benzoyl amidoacetic acid |
| Chemical formula | C9H9NO3 |
| Molecular mass | 179.17 g/mol |
| CAS number | [495-69-2] |
| Density | ? g/cm3 |
| Melting point | 187-188 °C |
| Boiling point | 240 °C (decomp.) |
| SMILES | O=C(O)CNC(C1=CC=CC=C1)=O |
| Disclaimer and references | |
Hippuric acid (Gr. hippos, horse, ouron, urine) is an organic acid found in the urine of horses and other herbivores. High concentrations of hippuric acid can also indicate a 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 in 1829 showed 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.[2] It is also formed by heating benzoic anhydride with glycine, [3] 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 hydrolysed by hot caustic alkalis to benzoic acid and glycine. Nitrous acid converts it into benzoyl glycolic acid, C6H5C(=O)OCH2CO2H. Its ethyl ester reacts with hydrazine to form hippuryl hydrazine, C6H5CONHCH2CONHNH2, which was used by Theodor Curtius for the preparation of azoimide.
[edit] References
- ^ Merck Index, 11th Edition, 4636.
- ^ Ann. 87, p. 325
- ^ Theodor Curtius, Ber., 1884, 17, p. 1662
- This article incorporates text from the Encyclopædia Britannica Eleventh Edition, a publication now in the public domain.
