In the previous post, we mentioned that carbohydrates exist mainly in their cyclic forms when 5- or 6-membered rings are possible. Remember also that cyclic carbohydrates are hemiacetals which can be further transformed into acetals. The acetals of monosaccharides are … Read more
In the previous post, we talked about the α and β anomers of glucose which are hemiacetals formed as a result of intramolecular cyclization. Anomers are diastereomers and as expected the glucose isomers can be isolated and characterized separately showing … Read more
In today’s post, we will discuss the conversion between Fischer, Haworth, and Chair forms of carbohydrates as well as the mechanism that leads to the formation of É‘-D-glucose and β-D-glucose from the open form of glucose. We mentioned the formation … Read more
Epimers In the previous post, we listed most of the naturally occurring D aldoses and ketoses together with their enantiomeric L isomers. As a reminder, all the stereogenic centers are inverted when comparing D and L isomers since they are … Read more
In the first post about carbohydrates, we mentioned that depending on the position of the carbonyl (C1 or C2) the sugar molecule can be an aldehyde or a ketone which are classified as an Aldose or a Ketose.   Today, we will … Read more
Although the R and S system, we are familiar with, can be used to designate the absolute configuration of chiral centers in carbohydrates, an older method, proposed in 1906 by a New York University chemist, M. A. Rosanoff, is often … Read more
Erythro and threo are common terms in stereochemistry used for naming molecules with two stereogenic centers. The names derive from the saccharides erythrose and threose, so let’s draw their Fischer projection to understand the basis of this notation:   … Read more
Carbohydrates, also known as sugars and starches, are one of the most important classes of compounds found in nature. Listing only a few examples would include the energy produced in our bodies by breaking down sugars, which are used in … Read more
To determine the R and S configuration of the chiral carbon atoms in a Fischer projection, we first need to recall the concept of the Fischer projection. And that is, the horizontal groups are pointing towards the viewer (wedge), and … Read more
