3-Methyl-2-oxobutanoate
2-oxo-3-methylbutanoate
2-oxoisovalerate
2-oxoisopentanoate
3-Methyl-2-oxobutyric acid
alpha-Ketovaline
2-Ketovaline
2-Keto-3-methylbutyric acid

C5H8O3

It's an a-keto acid (molecule formed after the deamination of an amino acid - in this case valine)

Synthesis of alanine, isoleucine, valine and leucine (3D)
Catabolism of methionine, threonine, valine and leucine (3D)
Pantothenate and CoA biosynthesis (Kyoto University)