SUBJECTS hippuric acid

Ikeda M, Ohtsuji H. 1969. Hippuric acid, phenol, and tricholoacetic acid levels in the urine of Japanese subjects with no known exposure to organic solvents. Br J Ind Med 26 162-164. 

After oral administration of 7- C-2,6- H-benzoic acid in healthy human subject (4.2 mg/kg), the drug was found to be quantitatively biotransformed to hippuric acid and excreted in urine within 4 hours [43]. 

Figure 5. Time course of enrichment of N-7 of uric acid compared with the range of enrichment values of urinary hippuric acid. (Open circles represent data on control subjects R.H. and F.L.)...

Figure 9. Time courses of enrichment of various nitrogenous products of urine in subject O.G. (H = hippuric acid, N = ammonia, A - amide-N of glutamine, 7 = N-7 of uric acid, 3/9 = of...

So, when p-methoxybenzaldehyde is allowed to react with hippuric acid (N-benzoylglycine), not only does aldol condensation occur but the product of that condensation is also subject to cyclization to an azlactone. Reduction and hydrolysis of the azlactone (oxazolone) produces an amino acid and benzoic acid, and, since a methoxy group is present in this particular synthesis, its cleavage is required and thus reduction here was effected with red phosphorus and HI. These reactions are shown in Scheme 12.43. 

A simple case of the general transpeptidation reaction was the trans-amidation resulting in the formation of hippuric anilide from aniline and hippuric amide in the presence of papain. Since this reaction proceeded much faster than the enzymatic synthesis of hippuric anilide from hippuric acid and aniline, it seems reasonable to infer that exchange, in the former reaction, took place between the aniline and ammonia. Waley and Watson subjected L-lysyl-L-tyrosyl-L-lysine and L-lysyl-L-tyrosyl-L-leucine to treatment with chymotrypsin and trypsin at pH 7.8. In the hydrolysis mixture of either of these substrates they were able to identify lysyllysine which could have arisen only by rearrangement of the amino acids in peptide bond. The peptide may have reacted with the lysine liberated by hydrolysis ... 

Small doses of benzoic acid were administered periodically to two controls (R.H. and F.L.) and three gouty subjects (S.G., R.Jo. and O.G.), in order to sample body glycine [28]. Hippurate was isolated from urine collected during the next few hours. The... 

Aromatic acids other than hippuric and 4-hydroxyphenylacetic acid and a few of exogenous (dietary) origin are generally observed in urine from normal subjects at very low levels, if at all, since those acids that occur in normal... 

---