Lactaldehyde

Lactaldehyde is an intermediate in the methylglyoxal metabolic pathway. Methylglyoxal is converted to -lactaldehyde by glycerol dehydrogenase (gldA). Lactaldehyde is then oxidized to lactic acid by aldehyde dehydrogenase.

Lactaldehyde exists in several forms: in open-chain form and as cyclic hemiacetal; in solution and in crystal forms; as monomer and as dimer. In crystal form, three conformers occur as hemiacetal dimers with a 1,4-dioxane ring skeleton:

In equilibrium solution, negligibly small amounts of the monomer and at least one five-membered ring dimer exist.