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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 and used by chemists, particularly in organic chemistry and biochemistry .
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 further from the observer. Atom 5 and the other atoms are the furthest. The groups below the plane of the ring in Haworth projections correspond to those on the right-hand side of a Fischer projection. This rule does ...
2, 3 = Haworth projections. 4 = Mills projection. Every two anomers are designated alpha (α) or beta (β), according to the configurational relationship between the anomeric centre and the anomeric reference atom , hence they are relative stereodescriptors . [ 2 ]
Haworth Projection of β-D-glucopyranose Hermann Emil Fischer won the Nobel Prize in Chemistry (1902) for his work in determining the structure of the D - aldohexoses . [ 1 ] However, the linear, free-aldehyde structures that Fischer proposed represent a very minor percentage of the forms that hexose sugars adopt in solution.
The Fischer projection is a systematic way of drawing the skeletal formula of an acyclic monosaccharide so that the handedness of each chiral carbon is well specified. Each stereoisomer of a simple open-chain monosaccharide can be identified by the positions (right or left) in the Fischer diagram of the chiral hydroxyls (the hydroxyls attached ...
Fischer projection: Skeletal formula: Ball-and-stick model: While the optical rotation of glyceraldehyde is (+) for R and (−) for S, this is not true for all ...
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Otherwise, if the carbonyl position is 2 or 3, the sugar is a derivative of a ketone, and is called a ketohexose, a special case of ketose; specifically, an n-ketohexose. [1] [2] However, the 3-ketohexoses have not been observed in nature, and are difficult to synthesize; [5] so the term "ketohexose" usually means 2-ketohexose.