Anhydro-alditols

Alditols Acyclic Alditols Anhydro-Alditols Amino-Alditols... 

If the anomeric hydroxy group is replaced by a hydrogen atom, the compound is named as an anhydro alditol (2-Carb-26). 

Intramolecular cyclization can also be effected with acyclic intermediates derived from such readily available alditols as D-mannitol. Kuszmann and Vargha63 reported the formation of 2,5-anhydro-l,6-dibromo-l,6-dideoxy-4-0-(methylsulfonyl)-D-glucitol (63), in 73% yield, by boiling 3,5-di-0-acetyl-l,6-dibromo-l,6-dideoxy-2,4-di-0-... 

Reference has already been made to the formation of anhydro sugars under the influence of acid (see Section XI, p. 87). In a similar manner, alditols may be converted into anhydroalditols, and these may be difficult to distinguish from other polyhydric compounds of low molecular weight. Such a problem arises in the hydrolyzates of cell walls, where ribitol and glycerol are present. It has been shown, however, by Gregory that glycerol and an anhydroribitol may be separated readily as their trimethylsilyl ethers.401... 

The key sequence in the determination of the structures of 2,5-anhydro-D-mannose (2) and -D-talose (4) was their reduction to the corresponding 2,5-anhydroalditols (5 and 6) and identification of the asymmetric dialdehyde (7) resulting from oxidation of the anhydro-alditols with periodate.37,43... 

Other examples of the solvolysis of sulfonates to give oxolanes have been reported. Thus, when 2,3-0-benzylidene-tri-0-(methylsulfonyl)-D-arabinitol, in a mixture of 9 M acetic acid and 10 M hydrochloric acid is heated for 30 minutes at 100°, it gives 2,5-anhydro-l,4-di-0-(methylsulfonyl)-D-arabinitol.88 Additional instances of the formation of internal anhydrides (not always well characterized) by acid hydrolysis of various sulfonic esters of alditols have been given by the same authors.88... 

Defaye19 called attention to the fact that the 2,5-anhydro-tri-0-(p-nitrobenzoyl)-D-lyxitol that he prepared is the enantiomorph of Barker and Fletcher s 1,4-anhydro-tri-0-(p-nitrobenzoyl)-L-arabinitol.l4alditol anhydrides derived, without Walden inversion, from two configurationally different sugars have been shown experimentally to possess the same, although enantiomorphic, configuration. 

Anhydroalditol compounds of a rather unusual type are the C-glycosyl compounds (erroneously called C-glycosides ). As pointed out by Treibs,33 these are not glycosides, but they are anhydro-alditols.3 A variety of approaches has been employed for synthesis of... 

The synthesis of an alditol having a 4-membered (oxetane) ring was first reported by Ustyuzhanin and coworkers,50 who prepared 1,3-anhydro-5,6-di-0-methyl-2,4-0-methylene-D-glucitol by saponification of the 1-p-toluenesulfonate of the corresponding derivative of D-... 

It is probable that the two 1,3-anhydro compounds just described are anhydrides of the same alditol. The compound of Ustyuzhanin and coworkers50 is unequivocally a 1,3-anhydro-D-glucitol derivative, because the hydroxyl groups at C-2, 4,5, and 6 were protected prior to the ring formation. Positive identity of the two would have been achieved by converting the monomethyl ether obtained by Haslam... 

Hough and Richardson58 explored the reaction of unacetylated hexose dithioacetals with peroxypropanoic acid the sulfone 15 initially formed is only marginally stable, and undergoes dehydration to mixtures of the unsaturated disulfone (18) and the 2,6-anhydro-l-deoxy-l,l-bis(ethylsulfo-nyl)alditol (19). All three products are degraded by aqueous ammonia to the next lower sugar (16) and bis(ethylsulfonyl)methane (17). This degradation is much slower for 18 than for 15, and it was concluded that hydration of 18 to 15 precedes disproportionation (Scheme 8). 

Access to 1,4-anhydro-D-alditols by radical reduction has received only limited attention, but the most detailed work concerns the reduction of protected glycofuranosyl isocyanides on heating for 2 h at 80 °C in toluene in the presence of /J-BU3S11H (2 eq) and AIBN.188 In particular, 2,3,5-tri-0-benzoyl-0-D-ribofuranosyl isocyanide (53) was converted in 78% yield into l,4-anhydro-2,3,5-tri-0-benzoyl-D-ribitol (54) also accessible from phenyl 2,3,5-tri-0-benzoyl-1 -thio-D-ribofuranoside (55).189... 

Enhancement Factors 1 for Paper-chromatographic Mobility of Alditols, Inositols, and Anhydro Compounds by Phenylboronic Acid... 

Alditol Enhancement factor" Inositols and anhydro compounds Enhancement factor"... 

The following Tables record some physical properties of boronates of sugars, glycosides, C- and N-glycosyl compounds including nucleosides, alditols, and anhydro sugars. 

The simplest known sugar derivatives that interact with the jack-bean lectin are l,5-anhydro-2-deoxy-D-arahino-hexitol and 1,4-anhydro-D-arabinitol.168,215 These alditols contain the minimal structural features required for binding to con A, namely, unmodified hydroxyl groups of the B-arabino configuration at C-3, C-4, and C-5 of the... 

From the oxo reaction of 3,4,6-tri-O-acetyl-D-galactal (36) (after deacetylation of the mixture of products), there was obtained, in almost quantitative yield, 2,6-anhydro-3-deoxy-D-golacto-heptitol (37) and 2,6-anhydro-3-deoxy-D-foio-heptitol (38). - Structural investigations of these anhydrodeoxyalditols paralleled those on the alditols obtained from 3,4,6-tri-O-acetyl-D-glucal. The absolute structures of compounds (37) and (38) were unequivocally established by correlation, as shown, with 2,6-anhydro-3-deoxy-D-gZuco-heptitol (27). Prior structural work" on compound (37), with the aid of periodic acid degradations only, had led to an incorrect, tentative assignment of structure. 

Attempts to use 4,5,7-tri-0-acetyl-2,6-anhydro-l,3-dideoxy-l-iodo-D-giuco-heptitol for x-ray analysis were unsuccessful, because only twinned crystals could be prepared. Use of die deacetylated p-toluenesulfonate, namely, 2,6-anhydro-3-deoxy-l-0-p-tolylsulfonyl-D-gl co-heptitol, and of the parent alditol, 2,6-anhydro-3-deoxy-D-glaco-hepti-tol, was unsuccessful because no atom of sufficient electron density was present. 

The preparation of a number of a,b>-dimethanesuIfonates of alditols has been described. For example, by treating l,2 5,6-dianhydro-3,4-di-O-isopropylidene-D-mannitol with methanesulfonic acid, 1,6-di-0-(methylsulfonyl)-D-mannitol was formed. It is noteworthy that treatment of l,2-anhydro-3-deoxy-DL-glycerol with p-toluenesulfonic acid gave 3-deoxy-l-O-p-tolylsulfonyl-DL-glycerol and 3-deoxy-2-O-p-tolylsulfonyl-DL-glycerol. 

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