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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 ]
The use of Fischer projections in non-carbohydrates is discouraged, as such drawings are ambiguous and easily confused with other types of drawing. The main purpose of Fischer projections is to show the chirality of a molecule and to distinguish between a pair of enantiomers. Some notable uses include drawing sugars and depicting isomers. [1]
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. [118] [145] The erythro diastereomers are pressor amines, a property not shared with the threo ...
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).
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.
A DAY IN THE LIFE OF A DOMESTIC WORKER: CARIBBEAN IMMIGRANT WOMEN AND THE CAMPAIGN FOR FAIR LABOR STANDARDS (with related Policy Recommendations) By ARLENE M. ROBERTS, ESQ.
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.