Chlorine from sucralose

Sucralose, Developed in England during the mid-1980s, testing and evaluation commenced in 1988. The structural formula of the compound (a chlorinated disaccharide derived from sucrose) is shown below. 

The sweetener aspartame was discovered in 1965 and approved by the FDA in 1981. It is the methyl ester of a dipeptide formed from the amino acids aspartic acid and phenylalanine. Because both of these amino acids occur naturally and arc part of nearly every protein, there is much less reason to be concerned about the health effects of this compound. Nevertheless, it has been extensively tested. Aspartame is about 180 times sweeter than sucrose, so the amount that is needed to sweeten a can of a soft drink, for example, is so small that it contributes only negligible calories to the diet. In addition, the taste profile of aspartame is much closer to sugar than is that of saccharin. Aspartame, sold under the brand name NutraSweet, has been an enormous financial success. Sucralose (Splenda) is prepared from sucrose by replacing some of the hydroxy groups with chlorines. Its taste closely resembles sucrose, but it is about 600 times sweeter. Acesulfame K (Sunett, Sweet One) is about 200 times sweeter than sucrose. It is quite stable to heat, so it is potentially very useful in baked goods. 

Fig. 9 Straightforward and efficient reaction pathway from sucrose to sucralose. R = Ac or Bz. (a) Organotin-mediated selective acylation 1. Starmoxane ester formation, 2. Acylation, (b) Selective chlorination by Vilsmeier type reaction DMF/acid chloride/AT. (c) Deacylation basic condition (e.g., NaOMe/MeOH)...

Note that sucralose (marketed under the trade name Splenda) differs from sucrose in the substitution of chlorine for three hydroxyls. 

The low cost of sucrose makes it an attractive synthetic precursor for a wide range of applications (56), and a chlorinated derivative (l,6-dichloro-6-deoxy-(3-D-fructofuranosyl 6-chloro-4,6-dideoxy-a-D-galactopyranoside, sucralose) is widely used as a noncaloric sweetener (Splenda ). Various other oligosaccharides occur naturally in the free form (57), but far more have been isolated as fragmentation products from larger biomolecules their chemical or enzymatic synthesis is a very active current area of research, as detailed in Chapters 3 and 4. 

Splenda is a commercial name for an artificial sweetener, like NutraSweet or Equal . Sucralose is the key sweet ingredient in Splenda , but unlike natural sugar molecules, sucralose is not metabolized, so it effectively has zero calories. It s made from regular table sugar by selectively exchanging three OH groups for chlorine atoms. 

The most familiar of all sugars is sucrose—the mixed acetal formed from glucose and fructose. Sucrose is of course sweet, and is easily metabolized into fats. But if three of the OH groups in sucrose are replaced by chlorine atoms, a compound 600 times as sweet is produced less of it is needed to get the same sweet taste and the chlorines reduce the rate of metabolism so that much less fat is made. This is the compound sucralose, discovered by chemists at Tate Lyle and now used to sweeten soft drinks. 

Sucralose, which is known as Splenda, is made from sucrose by replacing some of the hydroxyl groups with chlorine atoms. 

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