Naturally occurring sugars

There is no shortage of compounds nat ural or synthetic that taste sweet The most familiar are naturally occurring sugars especially su crose glucose and fructose All occur naturally with... 

Another naturally occurring sugar is fructose, also CsHijOe. It is an isomer of glucose but the... 

Many naturally occurring sugars have a sulfate group attached to one of the carbon atoms. Because the sulfate group does not have any transitions... 

In 2003 Handy and coworkers [65] described the first synthesis of ionic liquids from naturally occurring sugars. They exploited the transformation of D-fructose (1) into monosubstituted imidazoles developed more than 50 years ago by Trotter and Darby [66], to prepare 2 in 61% yield (Scheme 1). 

Sorbitol is a naturally occurring sugar found in a wide range of fruits. It was first isolated in 1872 from mountain ash berries, and the berries of the Sorbus genus are still the richest source of this chemical [3]. 

Several papers describe the preparation of analogs that differ from naturally occurring sugar nucleotides in the anomeric configuration of the glycosyl residue.270,271,297,309 Furthermore, it has been possible to obtain an analog (67) of uridine 5 -(a-D-glucopyranosyl pyrophos-... 

The diversity of the structures of naturally occurring sugar nucleotides and of their enzymic reactions has been described in this Chapter. The question now arises as to whether the recognition processes are unique for each enzyme-substrate pair, or whether there exist some common features between different enzymes in this respect. The latter possibility seems more attractive and, more importantly, it is supported by some experimental evidence. 

There exist many naturally occurring sugars in which a hydroxyl group of a monosaccharide is replaced by an amino or a thiol group. These compounds, commonly called amino or thio sugars, play a wide variety of important biological roles. Representative examples of these classes are 2-acetamido-2-deoxy-a-D-glucose (1) and 7-(5-S-methyl-5-thio-/ -D-ri-bosyl)adenine (vitamin L2,2). The former is the product of hydrolysis of... 

Scheme 1 Naturally Occurring Sugar Amino Acids[3 81...

Historically, soft drinks were refreshing beverages that copied or extended fruit juices. Fruit juices typically have around 10-12% naturally occurring sugars... 

Lactose, C12H22O1 j, is a naturally occurring sugar found in mammalian milk. A 0.335 M solution of lactose in water has a density of 1.0432 g/mL at 20°C. What is the concentration of this solution in the following units ... 

In almost all procedures for various chiral 6-hydroxyalkylpterin derivatives as well as those for biopterin (30) and neopterin (31), preparation of the chiral building block for the C(6) substituent has been carried out using naturally occurring sugar derivatives. This method is conceptually natural since the hy-droxypropyl side chains of 30 and 31 are derived from D-ribose of guanosine... 

Various attempts to synthesize biopterin independent of naturally occurring sugars have been carried out (Scheme 11). L-Tartalic acid and (S)-lactic acid were converted to 5-deoxy-L-arabinose (62) and its derivative (67), respectively [76-78]. However, these procedures required multiple steps and cannot be replaced by the procedure using L-rahmnose (65). The stereoselective process of biopterin 7-carboxylic acid (68) starting from E-2-butenoic acid, which is a bulk industrial chemical, looked attractive because the process is thoroughly independent of natural chiral resources, however, it is not applicable to the synthesis of biopterin (30) [79]. 

Terms describing sugars often reflect these first two criteria. For example, glucose has an aldehyde and contains six carbon atoms, so it is an aldohexose. Fructose also contains six carbon atoms, but it is a ketone, so it is called a ketohexose. Most ketoses have the ketone on C2, the second carbon atom of the chain. The most common naturally occurring sugars are aldohexoses and aldopentoses. 

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