 They are usually named after the positions on each molecule that form the bond between them.Included in the group are 8,5'-DiFA (DC) (or decarboxylated form) and 8,8'-DiFA (THF) (or tetrahydrofuran form), which are not true diferulic acids, but probably have a similar biological function.The 8,5'-DiFA (DC) lost CO2 during its formation, the 8,8'-DiFA (THF) gained H2O during its formation.