Sucrose derivatives

Sucrose derivatives Sucrose 6,6y-dithiol Sucrose 6,6y-episulfide Sucrose esters... 

To date (ca 1996) many potentially usefiil sucrose derivatives have been synthesized. However, the economics and complexities of sucrochemical syntheses and the avadabiLity of cheaper substitutes have limited their acceptance hence, only a few of them are in commercial use. A change in the price and availability of petroleum feedstocks could reverse this trend. Additional impetus may come from regioselective, site-specific modifications of sucrose to produce derivatives to facilitate and improve the economics of sucrochemical syntheses. For example, the microbe yigwbacterium tumifaciens selectively oxidizes sucrose to a three-keto derivative, a precursor of alkylated sucroses for detergent use (50). Similarly, enzymes have been used for selective synthesis of specific sucrose derivatives (21). 

Sucrochemistry has seen rapid advances since the 1960s. Whereas weU-characterized sucrose derivatives numbered only about 15 in 1965, over 300 weU-identified sucrose compounds have been described more recendy in the Hterature (1). 

Acetates. Because of the significant interest in selective acetylation reactions of sucrose, the need for a convenient and unambiguous method of identification has been recognized (34,35). The position of an acetyl group in a partially acetylated sucrose derivative can be ascertained by comparison of its H-nmr acetyl methyl proton resonances after per-deuterioacetylation with those of the assigned octaacetate spectmm. The synthesis of partially acetylated sucroses has generally been achieved either by way of selectively protected derivatives such as trityl ethers and cychc acetals or by direct selective acetylation and deacetylation reactions. 

Benzoates. The selective debenzoylation of sucrose octabenzoate [2425-84-5] using isopropylamine in the absence of solvents caused deacylation in the furanose ring to give 2,3,4,6,1/3/6 -hepta- and 2,3,4,6,1/6 -hexa-O-benzoyl-sucroses in 24.1 and 25.4% after 21 and 80 hours, respectively (54). The unambiguous assignment of partially benzoylated sucrose derivatives was accompHshed by specific isotopic labeling techniques (54). Identification of any benzoylated sucrose derivative can thus be achieved by comparison of its C-nmr carbonyl carbon resonances with those of the assigned octabenzoate derivative after benzoylation with 10 atom % benzoyl—carbonyl chloride in pyridine. 

Glucose Isomeriza.tion, Enzymatic isomerization of glucose to fmctose provides a real alternative to sugar (sucrose) derived from sugarcane or sugarbeets. The commercial product obtained is known as high fmctose com symp (HECS). Two grades of the symp have become estabUshed on the world market, HECS-42 and HECS-55, which contain 42 and 55% fmctose on dry substance basis. These products account for over one-third of the caloric sweetener market ia the United States. 

Some simplified assumptions for extracting interproton relaxation-contributions from a single set of nonselective relaxation-rates have been made for a tetrachlorotetra-0-mesyl-ga/ac(o-sucrose derivative (43). By con-... 

Sucrose is one of the leading world-commodities its current annual production in all forms exceeds ninety million tons. The potential of this regenerable, almost ubiquitous, natural product as a chemical raw-material has been extensively explored. However, the actual commercial success achieved has, so far, been insignificant. This can be attributed primarily to the lack of understanding of the basic chemistry of sucrose. During the last decade, efforts have, therefore, been concentrated on the study of the fundamental aspects of the chemistry of this molecule. The development of improved, or modem, synthetic methods and analytical techniques has led to the preparation and characterization of a large number of sucrose derivatives on which its commercial utilization may hopefully be based. 

Three surveys on the chemistry of sucrose have appeared during the past five years.1-3 Nevertheless, as progress in this field has been rapid, a further article on this subject is now justified. In this Chapter, an attempt has been made to collate information on the reactions of sucrose, and to illustrate some of the physical methods that have contributed to the characterization of sucrose derivatives. In addition, some of the potential commercial applications of compounds derived from sucrose have been considered briefly. 

The value of H n.m.r. spectroscopy in determining the structures of carbohydrates is well recognized. In this Section, some of the important features observed in the 100-MHz, H n.m.r. spectra of sucrose derivatives will be discussed, and the potential of I3C nuclear magnetic resonance spectroscopy will be very briefly indicated. Horton and his colleagues162 discussed the high resolution, 4H n.m.r. spectra of octa-O-acetylsucrose (75). The chemical shifts and cou-... 

Sucrose acrylate derivatives, 23 480 Sucrose concentration, polarimetric determination of, 23 473 Sucrose derivatives, 23 480 Sucrose esters, 23 480 Sucrose hydrolysis, 23 462 Sucrose monoesters (SMEs), 23 480, 481 Sucrose polyester, 23 481 Sucrose separation... 

Though there is no direct evidence that the D-fructofuranose unit in melezitose is of -configuration, the facts that all naturally occurring fructofuranoside sugars known so far are sucrose or sucrose derivatives and that the equilibrium mixture of D-fructose appears to consist almost entirely of /3-o-fructopyranose and /3-D-fructo-furanose, are very suggestive of a /3-configuration. For a full discussion of the problem see C. S. Hudson, Advances in Carbohydrate Chem., II, 1 (1946). 

Another representative highlight of the regioselective O-acylation work undertaken at QEC can be found in Richardson s selective O-pivaloylation of sucrose, which led to two papers with Les Hough and Manjit Chowdhary. One of these was on the regioselective O-pivaloylation itself, the other on the applications of the pivalate products in the preparation of various ring-modified sucrose derivatives. 

SCHEME 23. Some of the novel derivatives of sucrose derived from the 2,3-manno-sucrose epoxide by Hough, Richardson, Gurjar, and Sincharoenkul (1986). 

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