Quinoline-4-carboxylic acid (4-Carboxyquinoline) is a very important structure in a synthetic medicinal chemistry.

5-Phenylvaleric acid (Benzenepentanoic acid, Phenylpentanoic acid, Phenylvaleric Acid) is a Pentanoic acid of bacterial origin, occasionally found in human biofluids.

3-Furoic acid is an organic acid regularly occurring in urine of healthy individuals.

2-Hydroxy-3-methylbutanoic acid (3-Methyl-2-hydroxybutyric acid, 2-Hydroxyisopentanoic acid, 2-Oxyisovaleric acid) is a metabolite found in the urine of patients with phenylketonuria, methylmalonic acidemia, propionic acidemia, 3-ketothiolase deficiency, isovaleric acidemia, 3-methylcrotonylglycemia, 3-hydroxy-3-methylglutaric acidemia, multiple carboxylase deficiency, glutaric aciduria, ornithine transcarbamylase deficiency, glyceroluria, tyrosinemia type I, galactosemia, and maple syrup urine disease.

2-Methylheptanoic Acid is a flavouring ingredient.

Solvent Blue 35 (Sudan Blue II, Oil Blue 35) is a member of the Sudan family of hydrophobic fat-staining dyes, predominantly used for staining triglycerides in animal tissues (frozen sections).

Thiamine pyrophosphate hydrochloride (cocarboxylase) is a thiamine (vitamin B1) derivative which is produced by the enzyme thiamine diphosphokinase. It is a coenzyme of many enzymes, most of which occur in prokaryotes and is involved in the regulation of basic metabolism.

Inosine 5′-triphosphate (ITP) is used in studies on the impact of deamination of ATP and GTP by various enzymes and chemical processes.

trans-3-Indoleacrylic acid is a metabolite of tryptophan.

3-Chloro-L-tyrosine, a specific marker of myeloperoxidase-catalyzed oxidation, is markedly elevated in low density lipoprotein isolated from human atherosclerotic intima.