Trihydroxybutanals

The aldotetroses are the four stereoisomers of 2 3 4 trihydroxybutanal Fischer pro jections are constructed by orienting the molecule m an eclipsed conformation with the aldehyde group at the top The four carbon atoms define the mam chain of the Fischer projection and are arranged vertically Horizontal bonds are directed outward vertical bonds back... 

Diastereomers include all stereoisomers that are not related as an object and its mirror image. Consider the four structures in Fig. 2.3. These structures represent fee four stereoisomers of 2,3,4-trihydroxybutanal. The configurations of C-2 and C-3 are indicated. Each stereogenic center is designated J or 5 by application of the sequence rule. Each of the four structures is stereoisomeric wife respect to any of fee others. The 2R R and 25,35 isomers are enantiomeric, as are fee 2R, iS and 25,3J pair. The 21 ,35 isomer is diastereomeric wife fee 25,35 and 2R,3R isomers because they are stereoisomers but not enantiomers. Any given structure can have only one enantiomer. All other stereoisomers of feat molecule are diastereomeric. The relative configuration of diastereomeric molecules is fiequently specified using fee terms syn and anti. The molecules are represented as extended chains. Diastereomers wife substituents on the same side of the extended chain are syn stereoisomers, whereas those wife substituents on opposite sides are anti stereoisomers. 

When there is more than one stereocentre (chiral carhon) present in a molecule, it is possible to have more than two stereoisomers. It is then necessary to designate all these stereoisomers using the (i ) and (5) system. In 2,3,4-trihydroxybutanal, there are two chiral carbons. The chiral centres are at C-2 and C-3. Using the (R) and (5) system, one can designate these isomers as follows. 

If we look at structures A and C or B and D, we have stereoisomers, but not enantiomers. These are called diastereomers. Diastereomers have different physical properties (e.g. melting point). Other pairs of diastereomers among the stereoisomers of 2,3,4-trihydroxybutanal are A and D, and B and C. 

Buiunefriol and Derivatives Butanetriol, Methyl Glycerol or Trihydroxybutane,... 

Hydroxytetrahydrofuran has been obtained during the preparation of 1,2,4-trihydroxybutane,3 by hydrolysis of 4-chloro-methyl-l,3-dioxane2 and by acid catalyzed dehydration of 1,2,4-trihydroxybutane.4 The present procedure is similar to that described by Reppe.4... 

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