Sugar disaccharide

However, some microorganisms, the so-called anhydrobiotes, are able to deal better with a lack of water. One of their strategies for survival is the accumulation of non-reducing sugars (disaccharides) which replace the lost water during dry periods and can, for example, stabilise membrane structures, even when water is not present. 

Digestible carbohydrates include simple sugars, disaccharides, and polysaccharides (such as starches). 

Galactose (also known as milk sugar) Disaccharides Milk... 

Table 7 Preparation of deoxy sugar-sugar disaccharides 112-116 ...

Aliphatics HO-acids Monosaccharides Sugar Disaccharides Trisaccharides... 

Glycosylation by trityl sugars. Disaccharide formation catalyzed by AgC104-SnCl4 makes it possible to use the more stable trityl sugars (in situ detritylation) as nucleophiles. 

Considerable attention has been given to amino-sugar disaccharides. The 2-azido-2-deoxyglycosyl chloride procedure has been applied to obtain 2-amino-2-deoxy-a-D-glucopyranosyl a-D-glucopyranoside (trehalosamine)/ and the 2-deoxy-2-phthalamidoglycosyl bromide method to produce 6-0-(2-acetamido-... 

Amino-sugar Disaccharides. Oximinoglycosyl donor 96 has been coupled with four different sugar acceptor with NIS/TfOH as activator to give mainly a-linked products when the reactions were conducted in dichloromethane. In... 

Carbohydrates are divided into groups depending on how many monomers are combined by condensation polymerization monosaccharides (Latin saccharum, sugar ), disaccharides, trisaccharides (etc.), and polysaccharides. Monosaccharides are simple sugars that cannot be broken down into smaller carbohydrate units by acid hydrolysis. In contrast, hydrolysis of a disaccharide or trisaccharide yields two or three monosaccharides (either the same or different), while complete hydrolysis of a polysaccharide produces many monosaccharides (sometimes thousands of them). 

A highly novel and potentially very useful approach to 2-deoxy-sugar disaccharides depends on compound (19), the preparation and application of which are illustrated in Scheme 5. Sterlc control... 

Biological Activity of Sugars Disaccharides and oligosaccharides Sucrose... 

The synthesis of amino-sugar disaccharides incorporating muramic acid is mentioned in Chapter 4, and reference to several other amino-sugar disaccharides and higher saccharides is made in Chapter 3. 

Lactose is found in milk and other dairy products, so it is often called milk sugar. Disaccharides such as lactose need to be cleaved to monosaccharides in order to be absorbed into the bloodstream. The acetal bond in lactose is cleaved by the enzyme lactase. Many adults are lactose intolerant because their bodies don t make lactase. For such individuals, consumed lactose doesn t get absorbed into the bloodstream and the result is abdominal discomfort. 

Simple sugars, disaccharides and some oligosaccharides are frequently analyzed in various industries concerned with the preparation and stabilization of food. Their quantity in food and beverages is often a good indicator of product quality, contamination, and/or adulteration. It is also very important in... 

Methyl Ethers.— The methylation of partially acetylated sugars (e.g. methyl 2,3-di-O-acetyl-a-D-glucopyranoside, cellulose acetate) has been accomplished with methyl trifluoromethanesulphonate in the presence of a sterically hindered, weak base (e.g. 2,6-di-t-butylpyridine). Another novel procedure for methylation has used methyl iodide and anhydrous aluminium oxide in DMF. This procedure is claimed to be better than the modified Purdie procedure for the methylation of free sugars, disaccharides, and aldobiouronic acids. 

Carbohydrates are classified as monosaccharides (simple sugars), disaccharides (two monosaccharide units), or polysaccharides (many monosaccharide units). 

An enzyme which splits double sugars (disaccharides) such as lactose, maltose, and sucrose into single sugar units (monosaccharides) such eis fructose, galactose, and glucose. (Also see CARBOHYDRATE[S].)... 

In the area of deoi -sugar disaccharides L-rhamnose compounds have been given considerable attention, 2-O-a-L-rhamnosyl-L-rhamnoseJ 2-0-methyl-3-C)-(a-I/-rhanmosyl)-L-rhamnose, and 3-0-a-L-rhamnosyl-Z)-glucuronic acid having been prep>ared. 

There are three types of carbohydrate starch, non-starch polysaccharide and sugars. Of the simple sugars, disaccharides such as sucrose, maltose and lactose are far more abundant in the diet than monosaccharides such as glucose and fructose. All forms of carbohydrate that can be digested and absorbed can be converted to glycogen for storage in liver or skeletal muscle. 

---