Fructose 6-phosphate (also known as the Neuberg ester) is fructose sugar phosphorylated on carbon 6 (i.e., is a fructosephosphate). The ß-D-form of this compound is very common in cells. The vast majority of glucose and fructose entering a cell will become converted to this at some point. The name Neuberg ester comes from the German biochemist Carl Neuberg.