Anhydrides difructose

Historically, the trivial names diheterolevuloson 1, 11, III, and IV have been used to describe the di-D-fructose dianhydrides, which contain one or two pyra-nose rings. Similarly, the names di-D-fructose dianhydride (or difructose anhydride) 1,11, III, IV, and V have been used to describe those compounds in which two furanose rings occur. The names diheterosorhosan I and II have also been coined. Trivial names should not be used in other than a secondary manner for example, they may be listed in parentheses after the IUPAC name. 

In 1933, Schlubach and Knoop32 isolated a di-D-fructose dianhydride from Jerusalem artichoke and tentatively identified it as difructose anhydride I [a-D-Fru/-1,2 2,1 - 3-D-Fn / (5)]. Alliuminoside ( -D-fructofuranose- -D-fructofura-nose 2,6 6,2 -dianhydride) was isolated from tubers of Allium sewertzowi by Strepkov33 in 1958. Uchiyama34 has demonstrated the enzymic formation of a-D-Fru/-1,2 2,3 -(3-D-Fru/ [di-D-fructose anhydride III (6)] from inulin by a homogenate of the roots of Lycoris radiata Herbert. 

An extracellular enzyme [levan fructotransferase, (EC 2.4.1.10)] that carries out an intramolecular transfructosylation upon levan to produce (3-D-Fru/-2,6 6,2 -f)-D-Fru/ [difructose anhydride IV (7)] has been identified in A. ure-afaciens.54,55... 

An extracellular inulin fructotransferase that results in the formation of a-D-Fru/-1,2 2,1 -(3-D-Fru/ [difructose anhydride I (5)] has been purified from Arthrobacter globiformis S14-3,65,66 from Arthrobacter sp. MCI-249367 and from Streptomyces sp. MCI-2524.68... 

A mechanism was proposed31 for the formation of di-D-fructose dianhydrides from inulin and fructose. It was suggested that a-D-Fru/-1,2 2,1 - 3-D-Fru/ [difructose anhydride I (5)] formed first and then isomerized via ionic intermediates to produce the remaining products. Important support for the concept of the reversibility of the isomerization was the observation that ot-D-Frup-1,2 2,1 - 3-D-Frup (4) and p-D-Frup-1,2 2,1 - 3-D-Frup produced, upon treatment with HF, the same product mixture as did D-fructose. 

Difructose anhydride I Difructose anhydride II Difructose anhydride III Difructose anhydride IV Difructose anhydride V Alliuminoside... 

Montilla, A. et ah. Difructose anhydrides as quality markers of honey and coffee. Food Res. Int., 39, 801, 2006. 

Irisin — tetrafructose anhydride — difructose anhydride —> D-fructose. The difructose anhydride, although not isolated in pure form, was readily hydrolyzed by acid and thus differed from the difructose anhydrides isolated from inulin. 

Four difructose anhydrides have been isolated as well-defined crystalline compounds. The properties of these substances and their derivatives are recorded in Table II. 

Diheterolevulosan was first prepared by Pictet and Chavan67 by treating D-fructose with concentrated hydrochloric acid. Schlubach and Behre68 prepared the same compound by the action of liquid hydrogen chloride on dry fructose in a sealed tube. Sattler and Zerban6 have found this difructose anhydride in the unfermentable residue obtained from cane molasses. 

Molecular weight measurements agreed with the difructose anhydride composition. The matter of the anomeric structures of the D-fructoste units is left undecided because there is no evidence now known which relates to this question. 

Difructose anhydrides I, II, and III have been isolated from the nonreducing residue that remains after removal of D-fructose and d-glucose from acid-hydrolyzed inulin. 

Difructose anhydride I was first prepared by Jackson and Goergen.18-70 These authors found a molecular weight of 307 for the anhydride and 574 for the acetate, values which indicate its difructose anhydride composition. Almost simultaneously, Irvine and Stevenson71 prepared the acetate of what they believed to be an anhydrofructose by the action of concentrated nitric acid on inulin acetate. This anhydride was later shown72 to be identical with the difructose anhydride I of Jackson and Goergen. Hexamethyldifructose anhydride I waB hydrolyzed by Haworth and Straight7 and the trimethyl-D-fructose that was formed was identified as 3,4,6-trimethyl-D-fructofuranose by quantitative conversion... 

Difructose anhydrides II and III were first reported by Jackson and McDonald.74 In both cases molecular weight determinations indicated a difructose anhydride molecule. Difructose anhydride III has been shown by the following procedure78 to be 1,2 2,3 -di-D-fructofuranose anhydride. 

The rotations were measured in chloroform solution, a fact which is not stated in the original article. The hydrolysis curves for aqueous solution of difructose anhydride III indicate that the rotation in water of the resulting trimethyl-D-fructose is also within this range. 

The structure of difructose anhydride II has not yet been determined. McDonald and Jackson76 prepared its hexamethyl ether, which proved to be a crystalline compound melting at 73°. The behavior of the product from the acid hydrolysis of this hexamethyl derivative toward phenylhydrazine suggests that two different trimethyl-D-fructoses are present, the identification of which remains to be accomplished. Lately some evidence concerning the structure of this anhydride has been obtained by the use of per-iodic acid oxidation, as described on page 275. 

The polyfructosans, in contrast to the difructose anhydrides, are readily hydrolyzed in acid solution. Schlubach and his associates86 have measured the rates of hydrolysis of a large number of polyfructosans. The time required for 50% hydrolysis to take place in N sulfuric acid solution at 20° is recorded in Table III. These results are based on... 

The difructose anhydrides are much more stable toward acid hydrolysis. Using 0.2 N acid at 100°, Jackson and Goergen70 found that difructose anhydride I was 84.3% hydrolyzed in 100 minutes. Under the same conditions difructose anhydrides II and III were hydrolyzed,75 respectively, 64% in 100 minutes and 81% in 110 minutes. Schlubach and Knoop77 report the hydrolysis rates of difructose anhydride I and diheterolevulosan shown in Table IV. 

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