Direct Red 80 is a tetra azo dye. It can be used to detect amyloid and can magnify the usual birefringence of collagen fibers in tissue sections.

trans-2-Undecenoic acid ((E)-2-Undecenoic acid) is an α,β-unsaturated carboxylic acid and is characterized by acid dimers.

2-Hydroxy-2-methylbutyric acid is an unusual metabolite found in the urine of patients with 2-hydroxyglutaric aciduria and maple syrup urine disease.