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The natural isomer is D-erythrose; it is a diastereomer of D-threose. [3] Fischer projections depicting the two enantiomers of erythrose. Erythrose was first isolated in 1849 from rhubarb by the French pharmacist Louis Feux Joseph Garot (1798-1869), [4] and was named as such because of its red hue in the presence of alkali metals ...
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 second reaction is the organic reduction of 1,2-diphenyl-1-propanone 2 with lithium aluminium hydride, which results in the same reaction product as above but now with preference for the erythro isomer (2a). Now a hydride anion (H −) is the nucleophile attacking from the least hindered side (imagine hydrogen entering from the paper plane).
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). d-Ribulose is the diastereomer of d-xylulose. Ribulose sugars are composed in the pentose phosphate pathway from arabinose. [1] They are important in the formation of many bioactive substances.
A 10% solution, made from commercial grade sodium erythorbate, may have a pH of 7.2 to 7.9. [15] In its dry, crystalline state it is nonreactive. But, when in solution with water it readily reacts with atmospheric oxygen and other oxidizing agents, which makes it a valuable antioxidant.
The compound with the formula (C 5 H 5) 2 Fe 2 (CO) 4 exists as three isomers in solution. In one isomer the CO ligands are terminal. When a pair of CO are bridging, cis and trans isomers are possible depending on the location of the C 5 H 5 groups. [7] Another example in organometallic chemistry is the linkage isomerization of ...
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.
Erythorbic acid (isoascorbic acid, D-araboascorbic acid) is a stereoisomer (C5 epimer) of ascorbic acid (). [1] It is synthesized by a reaction between methyl 2-keto-D-gluconate and sodium methoxide.