Haworth projection

The Haworth is a named after the chemist Walter Norman Haworth representation for ring-shaped five - and six-membered molecules, such as glucose and fructose, in its cyclic form.

The molecule is drawn as a flat hexagon, pentagon respectively, although it is in the conformations of which are non-planar; in the case of six-membered rings usually predominantly in chair conformation. An included ring oxygen atom takes for rings with five atoms, the position in that corner, which points away from, so the pentagon to the opposite edge ( bond) is facing forward. In a six-membered ring oxygen is replaced by the back right corner. The carbon atoms follow in their numbering clockwise, but the first carbon atom does not have to necessarily get the # 1 position. Substituents (and occasionally hydrogen atoms) are vertically above or below the marked ring atoms. Substituents pointing in the Fischer projection to the right, stand in the Haworth projection down ( and vice versa), which allows the classification of a molecule by the Fischer nomenclature.

Note: FLEA - what is left at Fischer, is above in Haworth