In
chemistry, a Haworth projection is a common way of writing a
structural formula to represent the
cyclic structure of
monosaccharides with a simple three-dimensional perspective. Haworth projection approximate the shapes of the actual molecules better for
furanoses -which are in reality nearly planar- than for
pyranoses which exist in solution in the chair conformation.
Organic chemistry
Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.Clayden, ...
and especially
biochemistry
Biochemistry or biological chemistry is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided into three fields: structural biology, enzymology and ...
are the areas of chemistry that use the Haworth projection the most.
The Haworth projection was named after the British chemist Sir
Norman Haworth
Sir Walter Norman Haworth FRS (19 March 1883 – 19 March 1950) was a British chemist best known for his groundbreaking work on ascorbic acid ( vitamin C) while working at the University of Birmingham. He received the 1937 Nobel Prize in Chem ...
.
A Haworth projection has the following characteristics:
*
Carbon
Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon mak ...
is the implicit type of atom. In the example on the right, the atoms numbered from 1 to 6 are all carbon atoms. Carbon 1 is known as the
anomeric carbon.
*
Hydrogen
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...
atoms on carbon are implicit. In the example, atoms 1 to 6 have extra hydrogen atoms not depicted.
* A thicker line indicates atoms that are closer to the observer. In the example on the right, atoms 2 and 3 (and their corresponding OH groups) are the closest to the observer. Atoms 1 and 4 are farther from the observer. Atom 5 and the other atoms are the farthest.
*The groups below the plane of the ring in Haworth projections correspond to those on the right-hand side of a
Fischer projection
In chemistry, the Fischer projection, devised by Emil Fischer in 1891, is a two-dimensional representation of a three-dimensional organic molecule by projection. Fischer projections were originally proposed for the depiction of carbohydrates ...
. This rule does not apply to the groups on the two ring carbons bonded to the endocyclic oxygen atom.
See also
*
Skeletal formula
The skeletal formula, or line-angle formula or shorthand formula, of an organic compound is a type of molecular structural formula that serves as a shorthand representation of a molecule's bonding and some details of its molecular geometry. A ...
*
Natta projection
In chemistry, the Natta projection (named for Italian chemist Giulio Natta) is a way to depict molecules with complete stereochemistry in two dimensions in a skeletal formula. In a hydrocarbon molecule with all carbon atoms making up the backb ...
*
Newman projection
A Newman projection is a drawing that helps visualize the 3-dimensional structure of a molecule. This projection most commonly sights down a carbon-carbon bond, making it a very useful way to visualize the stereochemistry of alkanes. A Newman pro ...
References
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Carbohydrate chemistry
Carbohydrates
Stereochemistry