Ketonic parent sugars (polyhydroxyketones H–[CHOH]n–C(=O)[CHOH]m–H with three or more carbon atoms) and their intramolecularhemiacetals. The oxo group is usually at C-2. E.g. d-fructose:
Sources: PAC, 1995, 67, 1307. (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1346 [Terms] [Paper] White Book, 2nd ed., p. 129 [Terms] [Book]
