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Erythrose is a tetrose saccharide with the chemical formula C 4 H 8 O 4.It has one aldehyde group, and is thus part of the aldose family. The natural isomer is D-erythrose; it is a diastereomer of D-threose.
Two older prefixes still commonly used to distinguish diastereomers are threo and erythro. In the case of saccharides, when drawn in the Fischer projection the erythro isomer has two identical substituents on the same side and the threo isomer has them on opposite sides. [ 7 ]
Very often, cis–trans stereoisomers contain double bonds or ring structures. In both cases the rotation of bonds is restricted or prevented. [4] When the substituent groups are oriented in the same direction, the diastereomer is referred to as cis, whereas when the substituents are oriented in opposing directions, the diastereomer is referred to as trans.
Ribulose is a ketopentose — a monosaccharide containing five carbon atoms, and including a ketone functional group.It has chemical formula C 5 H 10 O 5.Two enantiomers are possible, d-ribulose (d-erythro-pentulose) and l-ribulose (l-erythro-pentulose).
Several isomers exist with the formula H−(C=O)−(CH 2)−(CHOH) 3 −H, but in deoxyribose all the hydroxyl groups are on the same side in the Fischer projection.The term "2-deoxyribose" may refer to either of two enantiomers: the biologically important d-2-deoxyribose and to the rarely encountered mirror image l-2-deoxyribose.
Four isomers of methylphenidate are possible, since the molecule has two chiral centers. One pair of threo isomers and one pair of erythro are distinguished, from which primarily d-threo-methylphenidate exhibits the pharmacologically desired effects. [119] [146] The erythro diastereomers are pressor amines, a property not shared with the threo ...
Discounting isomers that are equivalent under rotations, there are nine isomers that differ by this criterion, and behave as different stable substances (two of them being enantiomers of each other). The most common one in nature ( myo -inositol) has the hydroxyls on carbons 1, 2, 3 and 5 on the same side of that plane, and can therefore be ...
Threose is a four-carbon monosaccharide with molecular formula C 4 H 8 O 4.It has a terminal aldehyde group rather than a ketone in its linear chain, and so is considered part of the aldose family of monosaccharides.